阅读说明：本技术 光调制器、光观察装置以及光照射装置 (Optical modulator, optical observation device, and light irradiation device ) 是由 泷泽国治 田中博 丰田晴义 大林宁 酒井宽人 渡边翼 于 2017-12-05 设计创作，主要内容包括：光调制器具备：钙钛矿型的电光晶体,其具有输入输入光的输入面和与输入面相对的背面；第一光学元件,其具有配置于电光晶体的输入面,且透过输入光的第一电极；第二光学元件,其具有配置于电光晶体的背面,且透过输入光的第二电极；驱动电路,其向第一电极和第二电极之间施加电场,第一电极以单体配置于输入面,第二电极以单体配置于背面,第一电极及第二电极的至少一方部分地覆盖输入面或背面,电光晶体中的输入光的传播方向和电场的施加方向为平行,在输入面和第一电极之间及背面和第二电极之间的至少一方形成有抑制电荷注入到电光晶体内的电荷注入抑制层。(The optical modulator includes: a perovskite-type electro-optical crystal having an input surface to which input light is input and a back surface opposite to the input surface; a first optical element having a first electrode disposed on an input surface of the electro-optical crystal and transmitting input light; a second optical element having a second electrode disposed on the back surface of the electro-optical crystal and transmitting the input light; and a driving circuit for applying an electric field between the first electrode and the second electrode, wherein the first electrode is disposed on the input surface as a single body, the second electrode is disposed on the back surface as a single body, at least one of the first electrode and the second electrode partially covers the input surface or the back surface, a propagation direction of input light in the electro-optical crystal is parallel to an application direction of the electric field, and a charge injection suppression layer for suppressing injection of electric charges into the electro-optical crystal is formed between the input surface and the first electrode and between the back surface and the second electrode.)

1. A light modulator in which, among other things,

is an optical modulator that modulates input light and outputs modulated light,

the disclosed device is provided with:

a perovskite-type electro-optical crystal having an input surface to which the input light is input and a back surface opposite to the input surface, and having a relative dielectric constant of 1000 or more;

a first optical element having a first electrode disposed on the input surface of the electro-optical crystal and transmitting the input light;

a second optical element having a second electrode disposed on the back surface of the electro-optic crystal and transmitting the input light;

a drive circuit that applies an electric field between the first electrode and the second electrode,

the first electrode is arranged on the input surface side as a single body,

the second electrode is disposed on the back surface side as a single body,

at least one of the first electrode and the second electrode partially covers the input surface or the back surface,

the propagation direction of the input light in the electro-optical crystal and the application direction of the electric field are parallel,

at least one of the first optical element and the second optical element includes a charge injection inhibiting layer that inhibits injection of charge into the electro-optical crystal.

2. The light modulator of claim 1,

further provided with: a transparent substrate having a first surface facing the second optical element and a second surface that is a surface opposite to the first surface,

the transparent substrate outputs the input light transmitted through the second optical element.

3. A light modulator in which, among other things,

is an optical modulator that modulates input light and outputs modulated light,

the disclosed device is provided with: a perovskite-type electro-optical crystal having an input surface to which the input light is input and a back surface opposite to the input surface, and having a relative dielectric constant of 1000 or more;

a first optical element having a first electrode disposed on the input surface of the electro-optical crystal and transmitting the input light;

a second optical element having a second electrode disposed on the back surface of the electro-optic crystal, the second optical element reflecting the input light toward the input surface;

a drive circuit that applies an electric field between the first electrode and the second electrode,

the first electrode is arranged on the input surface side as a single body,

the second electrode is disposed on the back surface side as a single body,

at least one of the first electrode and the second electrode partially covers the input surface or the back surface,

the propagation direction of the input light in the electro-optical crystal and the application direction of the electric field are parallel,

an electric-charge-injection inhibiting layer that inhibits injection of electric charges into the electro-optical crystal is formed between the input surface and the first electrode and between the back surface and the second electrode.

4. The light modulator of claim 3,

further provided with: a substrate having a first face opposite the second optical element.

5. The light modulator of any of claims 1-4,

the charge injection inhibiting layers are formed between the input surface and the first electrode and between the back surface and the second electrode, respectively.

6. The light modulator of any of claims 1-5,

at least one of the first electrode and the second electrode has an area of 25d when a thickness of the electro-optical crystal in an electric field application direction of the electro-optical crystal is d²Wherein the unit of the area is μm²The thickness is in μm.

7. The light modulator of any of claims 1-6,

the area of the first electrode is larger or smaller than that of the second electrode.

8. The light modulator of any of claims 1-7,

the electro-optical device further includes a third electrode electrically connected to the first electrode and a fourth electrode electrically connected to the second electrode, and the third electrode and the fourth electrode are arranged so as not to overlap with each other with the electro-optical crystal interposed therebetween.

9. The light modulator of any of claims 1-7,

the first optical element has:

a third electrode electrically connected to the first electrode;

an insulating section disposed between the third electrode and the input surface, the insulating section shielding an electric field generated by the third electrode,

the drive circuit applies an electric field to the first electrode via the third electrode.

10. The light modulator of any of claims 1-9,

the first optical element has a light reduction portion that covers the input surface around the first electrode and reduces light input from the periphery of the first electrode to the input surface.

11. The light modulator of claim 10,

the light reducing portion is a reflective layer that reflects the light.

12. The light modulator of claim 10,

the light reducing portion is an absorption layer that absorbs the light.

13. The light modulator of claim 10,

the light reducing portion is a shielding layer that shields the light.

14. The light modulator of claim 3 or 4,

a dielectric multilayer film that reflects the input light is provided on the second electrode.

15. The light modulator of claim 3 or 4,

the second electrode reflects the input light.

16. The light modulator of any of claims 1-15,

the electro-optic crystal is KTa_1-xNb_xO₃Crystal, K_1-yLi_yTa_1-xNb_xO₃Crystals, or P L ZT crystals, wherein, in the KTa_{1- x}Nb_xO₃In the crystal, 0 ≦ x ≦ 1, where K is_1-yLi_yTa_1-xNb_xO₃In the crystal, x is 0 ≦ 1, and y is 0 < 1.

17. The light modulator of any of claims 1-16,

the electro-optical crystal is also provided with a temperature control element for controlling the temperature of the electro-optical crystal.

18. A light observation device, wherein,

comprising:

a light source that outputs the input light;

the light modulator of any of claims 1-17;

an optical system that irradiates the modulated light output from the optical modulator to an object;

and a light detector that detects light output from the object.

19. A light irradiation device, wherein,

comprising:

a light source that outputs the input light;

the light modulator of any of claims 1-17;

and an optical system for irradiating the modulated light output from the light modulator onto an object.

Technical Field

The invention relates to an optical modulator, an optical observation device, and a light irradiation device.

Background

For example, patent documents 1 and 2 disclose an electro-optical element. The electro-optical element includes: substrate, and KTN (KTa) of ferroelectric substance laminated on substrate_1-xNb_xO₃) The layer, dispose transparent electrode, the metal electrode of disposing behind the KTN layer in the front of the KTN layer. KTN has 4 crystal structures depending on temperature, and is used as an electro-optical element when it has a perovskite crystal structure. This KTN layer is formed on a seed layer formed on a metal electrode.

Disclosure of Invention

Problems to be solved by the invention

In the electro-optical element, the KTN layer is sandwiched between a pair of electrodes. The pair of electrodes is formed over the entire front and rear surfaces of the KTN layer. Therefore, when an electric field is applied to the KTN layer, the inverse piezoelectric effect or the electrostrictive effect becomes large, and there is a possibility that stable optical modulation cannot be performed. In addition, when injecting charges from the metal electrode into the KTN layer, there is a possibility that modulation accuracy is unstable due to the behavior of electrons in the KTN crystal.

An object of the present invention is to provide an optical modulator, an optical observation device, and a light irradiation device capable of performing stable optical modulation.

Means for solving the problems

An optical modulator according to an aspect is an optical modulator that modulates input light and outputs modulated light, and includes: a perovskite-type electro-optical crystal having an input surface to which input light is input and a back surface facing the input surface, and having a relative dielectric constant of 1000 or more; a first optical element having a first electrode disposed on an input surface side of the electro-optical crystal and transmitting input light; a second optical element having a second electrode disposed on the back surface side of the electro-optical crystal and transmitting the input light; and a drive circuit configured to apply an electric field between a first electrode and a second electrode, the first electrode being disposed on the input surface side as a single body, the second electrode being disposed on the rear surface side as a single body, at least one of the first electrode and the second electrode partially covering the input surface or the rear surface, a propagation direction of the input light in the electro-optical crystal being parallel to an application direction of the electric field, and at least one of the first optical element and the second optical element including a charge injection suppression layer configured to suppress injection of electric charges into the electro-optical crystal.

An optical modulator according to an aspect is an optical modulator that modulates input light and outputs modulated light, and includes: a perovskite-type electro-optical crystal having an input surface to which input light is input and a back surface facing the input surface, and having a relative dielectric constant of 1000 or more; a first optical element having a first electrode disposed on an input surface side of the electro-optical crystal and transmitting input light; a second optical element having a second electrode disposed on the back surface side of the electro-optical crystal, and reflecting the input light toward the input surface; and a drive circuit configured to apply an electric field between a first electrode and a second electrode, the first electrode being disposed on the input surface side as a single body, the second electrode being disposed on the rear surface side as a single body, at least one of the first electrode and the second electrode partially covering the input surface or the rear surface, a propagation direction of the input light in the electro-optical crystal being parallel to an application direction of the electric field, and at least one of the first optical element and the second optical element including a charge injection suppression layer configured to suppress injection of electric charges into the electro-optical crystal.

In addition, an optical observation device according to an aspect includes: a light source that outputs input light; the above-mentioned optical modulator; an optical system that irradiates the modulated light output from the optical modulator to an object; and a light detector for detecting light output from the object.

In addition, a light irradiation device according to an aspect includes: a light source that outputs input light; the above-mentioned optical modulator; and an optical system for irradiating the modulated light output from the light modulator onto the object.

According to the optical modulator, the optical observation device, and the light irradiation device, input light is transmitted through the first electrode of the first optical element and is input to the input surface of the perovskite-type electro-optical crystal. The input light can be transmitted through the second optical element disposed on the back surface of the electro-optical crystal and output, or can be reflected by the second optical element and output. At this time, an electric field is applied between the first electrode provided to the first optical element and the second electrode provided to the second optical element. This allows the input light to be modulated by applying an electric field to the electro-optical crystal having a high relative permittivity. In the optical modulator, the first electrode and the second electrode are disposed one by one, and at least one of the first electrode and the second electrode partially covers the input surface or the back surface. In this case, the inverse piezoelectric effect or the electrostrictive effect occurs in a portion where the first electrode and the second electrode face each other, but the inverse piezoelectric effect or the electrostrictive effect does not occur in the periphery thereof. Therefore, the periphery of the portion where the first electrode and the second electrode are opposed functions as a damper (damper). Thus, compared to the case where the entire input surface and the rear surface are covered with the electrodes, the inverse piezoelectric effect and the electrostrictive effect can be suppressed, and the occurrence of resonance or the like can be suppressed. Further, since the charge injection inhibiting layer for inhibiting injection of charge into the electro-optical crystal is formed, the behavior of electrons in the electro-optical crystal can be stabilized. Therefore, stable optical modulation can be performed.

In one aspect, the present invention may further include: and a transparent substrate having a first surface facing the second optical element and a second surface opposite to the first surface, the transparent substrate outputting input light transmitted through the second optical element. In one aspect, the present invention may further include: and a substrate having a first face opposite the second optical element. In these optical modulators, even when the thickness of the electro-optical crystal in the optical axis direction is formed to be thin, the electro-optical crystal can be protected from external impact or the like.

The charge injection inhibiting layer may be formed between the input surface and the first electrode, and between the back surface and the second electrode. According to this structure, charge injection into the electro-optical crystal from both the first electrode and the second electrode is suppressed.

In one embodiment, at least one of the first electrode and the second electrode has an area (μm)²) When the thickness (μm) of the electro-optical crystal in the electric field application direction of the electro-optical crystal is d, the thickness may be 25d²The following. In such an optical modulator, the inverse piezoelectric effect or the electrostrictive effect can be effectively reduced.

In one embodiment, the area of the first electrode may be larger or smaller than the area of the second electrode. In this case, the first electrode and the second electrode can be easily positioned.

In one aspect, the electro-optical device may further include a third electrode electrically connected to the first electrode and a fourth electrode electrically connected to the second electrode, and the third electrode and the fourth electrode may be arranged so as not to overlap with each other with the electro-optical crystal interposed therebetween.

In one aspect, the first optical element may include a third electrode electrically connected to the first electrode, and an insulating portion disposed between the third electrode and the input surface and configured to reduce an electric field generated by the third electrode, and the drive circuit may apply the electric field to the first electrode via the third electrode. Since the third electrode is provided for connection to the drive circuit, the size and position of the first electrode can be freely designed. In this case, the insulating portion can suppress the influence of the electric field generated by the third electrode on the electro-optical crystal.

In one aspect, one optical element may include: and a light reduction unit that covers the input surface around the first electrode and reduces light input from the periphery of the first electrode to the input surface. In this case, the light reducing portion may be a reflective layer that reflects light. The light reducing portion may be an absorbing layer that absorbs light. The light reducing portion may be a shielding layer for shielding light. This can suppress the input of light from the portion of the input surface where the first electrode is not formed.

In one embodiment, a dielectric multilayer film that reflects input light may be provided on the second electrode. According to this structure, the input light can be efficiently reflected.

In one aspect, the second electrode may reflect the input light. According to this structure, a reflective layer or the like does not need to be provided on the second electrode side.

In one aspect, the electro-optic crystal may be KTa_1-xNb_xO₃(0 ≦ x ≦ 1) crystal, K_1-yLi_yTa_1-xNb_xO₃(O ≦ x ≦ 1, O < y < 1) crystal, or P L ZT crystal.

In one embodiment, the electro-optical device may further include a temperature control element for controlling a temperature of the electro-optical crystal. According to this configuration, the modulation accuracy can be further stabilized by constantly maintaining the temperature of the electro-optical crystal.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the optical modulator, the optical observation device, and the light irradiation device of the embodiments, stable optical modulation can be performed while suppressing the inverse piezoelectric effect or the electrostrictive effect.

Drawings

Fig. 1 is a block diagram showing a configuration of an optical observation device according to an embodiment.

Fig. 2 is a schematic diagram of the optical modulator according to the first embodiment.

Fig. 3 is a diagram showing a relationship between a crystal axis, a light traveling direction, and an electric field in the retardation modulation.

Fig. 4 is a schematic diagram of an optical modulator according to a second embodiment.

Fig. 5 is a schematic diagram of an optical modulator according to a third embodiment.

Fig. 6 is a schematic diagram of an optical modulator according to a fourth embodiment.

Fig. 7 is a diagram schematically showing an optical modulator according to a fifth embodiment.

Fig. 8 is a schematic diagram of an optical modulator according to a sixth embodiment.

Fig. 9 is a schematic diagram of an optical modulator according to a seventh embodiment.

Fig. 10 is a schematic diagram of an optical modulator according to an eighth embodiment.

Fig. 11 is a schematic diagram of an optical modulator according to a ninth embodiment.

Fig. 12 is a schematic diagram of an optical modulator according to a tenth embodiment.

Fig. 13 is a block diagram showing a configuration of a light irradiation device according to an embodiment.

Detailed Description

Hereinafter, embodiments will be described in detail with reference to the drawings. For convenience of explanation, the same reference numerals are used for the same elements, and descriptions thereof may be omitted.

[ first embodiment ]

Fig. 1 is a block diagram showing a configuration of an optical observation device according to an embodiment, an optical observation device 1A is, for example, a fluorescence microscope for imaging an object to be observed, and the optical observation device 1A obtains an image of a sample S by irradiating the surface of the sample (object) S with input light L1 and imaging detection light L3 such as fluorescence or reflected light output from the sample S in association therewith.

The sample S to be observed is, for example, a sample such as a cell or a living body containing a fluorescent substance such as a fluorescent dye or a fluorescent protein, or a sample such as a semiconductor device or a thin film, the sample S may be a sample such as a semiconductor device or a thin film, the sample S generates, for example, detection light L3 such as fluorescence when irradiated with light (excitation light or illumination light) having a predetermined wavelength region, and the sample S is accommodated in, for example, a holder having transparency to at least the input light L1 and the detection light L3, and the holder is held on, for example, a table.

As shown in fig. 1, the optical observation device 1A includes: a light source 11, a condenser lens 12, an optical modulator 100, a first optical system 14, a beam splitter 15, an objective lens 16, a second optical system 17, a photodetector 18, and a controller 19.

The light source 11 outputs input light L1 having a wavelength that excites the sample S, for example, the light source 11 emits coherent light or incoherent light, examples of the coherent light source include a laser light source such as a laser diode (L D), and examples of the incoherent light source include a light emitting diode (L ED), a superluminescent diode (S L D), a lamp light source, and the like.

The condenser lens 12 condenses the input light L1 output from the light source 11 and outputs the condensed input light L1. the optical modulator 100 is disposed such that the propagation direction of the input light L1 and the direction of the applied electric field are parallel, therefore, in the optical modulator 100, the propagation direction of the input light L1 in the electro-optical crystal 101 and the direction of the applied electric field are parallel, the optical modulator 100 is an optical modulator that modulates the phase or delay (phase difference) of the input light L1 output from the light source 11. the optical modulator 100 modulates the input light L1 input from the condenser lens 12 and outputs the modulated light L2 toward the first optical system 14. the optical modulator 100 of the present embodiment is configured to be of a transmission type, but a reflection type optical modulator may be used in the optical observation device 1A. the optical modulator 100 is electrically connected to the controller 21 of the controller 19 to configure an optical modulator unit. the optical modulator 100 is controlled by the controller 21 of the controller 19 to drive the optical modulator 100, and the details of the optical modulator 100 will be described later.

The first optical system 14 optically couples the optical modulator 100 and the objective lens 16, whereby the modulated light L2 output from the optical modulator 100 is guided to the objective lens 16, for example, the first optical system 14 condenses the modulated light L2 from the optical modulator 100 at the pupil of the objective lens 16.

The beam splitter 15 is an optical element for separating the modulated light L2 and the detection light L3, the beam splitter 15 transmits the modulated light L2 of the excitation wavelength and reflects the detection light L3 of the fluorescence wavelength, for example, the beam splitter 15 may be a polarizing beam splitter or a dichroic mirror, and the beam splitter 15 may reflect the modulated light L2 and transmit the detection light L3 of the fluorescence wavelength depending on the optical system (for example, the first optical system 14 and the second optical system 17) before and after the beam splitter 15 or the type of microscope to be applied.

The objective lens 16 condenses the modulated light L2 modulated by the optical modulator 100, irradiates the sample S with the condensed light, and guides the detection light L3 generated from the sample S along with the condensed light, and the objective lens 16 is configured to be movable along the optical axis by a driving element such as a piezoelectric actuator or a stepping motor, whereby the condensed position of the modulated light L2 and the focal position for detecting the detection light L3 can be adjusted.

The second optical system 17 optically couples the objective lens 16 and the photodetector 18, whereby the detection light L3 guided from the objective lens 16 is imaged on the photodetector 18, and the second optical system 17 has a lens 17a for imaging the detection light L3 from the objective lens 16 on the light receiving surface of the photodetector 18.

The photodetector 18 picks up the detection light L3 guided by the objective lens 16 and imaged on the light receiving surface, and the photodetector 18 is, for example, an area image sensor such as a CCD image sensor or a CMOS image sensor.

The control unit 19 includes a computer 20 including a control circuit such as a processor, an image processing circuit, a memory, and the like, and a controller 21 including a control circuit such as a processor, a memory, and the like and electrically connected to the optical modulator 100 and the computer 20. The computer 20 is, for example, a personal computer, a smart device, a microcomputer, a cloud server, or the like. The computer 20 controls the operation of the objective lens 16, the photodetector 18, and the like by a processor, and executes various controls. In addition, the controller 21 controls the phase modulation amount or the delay modulation amount in the optical modulator 100.

Next, the optical modulator 100 will be described in detail, fig. 2 is a schematic diagram showing the optical modulator, the optical modulator 100 is a transmission type optical modulator that modulates an input light L1 and outputs a modulated light L2 after modulation, and as shown in fig. 2, includes an electro-optical crystal 101, a light input unit (first optical element) 102, a light output unit (second optical element) 106, and a drive circuit 110, and in fig. 2 (a), the electro-optical crystal 101, the light input unit 102, and the light output unit 106 of the optical modulator 100 are shown as a cross section, and fig. 2 (b) is a diagram showing the optical modulator 100 viewed from the light input unit 102 side, and fig. 2 (c) is a diagram showing the optical modulator 100 viewed from the light output unit 106 side.

The electro-optical crystal 101 is formed in a plate shape having an input surface 101a to which input light L1 is input and a back surface 101b facing the input surface 101a, and the electro-optical crystal 101 has a perovskite crystal structure, and uses electro-optical effects such as the Pockels effect and the Kerr effect for refractive index change, and is a perovskite crystalThe volume-structured electro-optical crystal 101 belongs to the cubic system of point group m3m, and is an isotropic crystal having a relative dielectric constant of 1000 or more. The relative dielectric constant of the electro-optical crystal 101 can be, for example, about 1000 to 20000. As such an electro-optical crystal 101, for example, KTa is given_1-xNb_xO₃(0 ≦ x ≦ 1) crystal (hereinafter referred to as "KTN crystal"), K_1-yLi_yTa_1-xNb_xO₃(O ≦ x ≦ 1, 0 < y < 1) crystal, P L ZT crystal, and the like, and specific examples thereof include BaTiO₃Or K₃Pb₃(Zn₂Nb₇)O₂₇、K(Ta_0.65Nb_0.35)P₃、Pb₃MgNb₂O₉、Pb₃NiNb₂O₉In the optical modulator 100 of the present embodiment, a KTN crystal is used as the electro-optical crystal 101. the KTN crystal is a group of m3m points of a cubic system, and therefore, modulation is performed by the kerr effect without the pockels effect, therefore, light can be input in parallel or perpendicular to the crystal axis of the electro-optical crystal 101, and when an electric field is applied in the same direction, phase modulation is performed, and further, if the other 2 axes are rotated at any angle other than 0 ° and 90 ° with any crystal axis as the center, delay modulation can be performed, (a) in fig. 3 is a perspective view showing the relationship between the crystal axis and the traveling direction of light and the electric field in delay modulation, and (b) in fig. 3 is a view showing each axis in a plane, and (c) in fig. 3 is an example in which the crystal is rotated at an angle of 45 °, in which axes X2 and X3 are rotated by 45 ° with axes X1 ' as the center, and when new axes X1 and X2 ', X3 ' are used, axes are rotated by 2 and 11 g, and finally, the directions of the input light can be modulated by the directions of application of electric field in which are parallel to the directions of m3, and 8291, 584, and the directions of the applied electric field applied, applied electric field, which are used in the directions of the applied to the input light, which is.

The relative permittivity of KTN crystal is easily affected by temperature, and for example, the relative permittivity is about 20000 at a maximum around-5 ℃, and is reduced to about 5000 at 20 ℃ at room temperature. Therefore, the temperature of the electro-optical crystal 101 is controlled to be near-5 ℃ by a temperature control element P such as a peltier element.

As shown in fig. 2, the light input unit 102 includes: a transparent electrode (first electrode) 103, an electric-charge-injection inhibiting layer 121, an intermediate layer 120, a connection electrode (third electrode) 104, and an insulating portion 105.

The transparent electrode 103 is disposed on the input surface 101a side of the electro-optical crystal 101, the transparent electrode 103 is formed of, for example, ITO (indium tin oxide), and transmits input light L1, that is, input light L1 transmits through the transparent electrode 103 and propagates toward the electro-optical crystal 101, in the present embodiment, the transparent electrode 103 is formed in, for example, a rectangular shape in plan view, partially covering the input surface 101a, and the area (μm) of the transparent electrode 103²) When the thickness of the electro-optical crystal 101 in the electric field application direction is d (μm), it may be 25d²The following. The transparent electrode 103 is formed as a single body at one position substantially in the center of the input surface 101a, and is spaced apart from the periphery of the input surface 101 a. Such a transparent electrode 103 can be formed by, for example, vapor deposition of ITO using a mask pattern.

The electric-charge-injection inhibiting layer 121 is formed between the transparent electrode 103 and the input surface 101 a. The charge injection inhibiting layer 121 is, for example, the same size as the transparent electrode 103, and is formed in a rectangular shape in a plan view. The charge injection inhibiting layer 121 contains a dielectric material in a cured product of a nonconductive adhesive material, for example, and does not contain a conductive material. The nonconductive property is not limited to the property of having no conductivity, and includes a property of high insulation or a property of high resistivity. That is, the charge injection inhibiting layer 121 has high insulation properties (high resistivity), and ideally has no conductivity.

The dielectric material may be, for example, a powder having a particle size of not more than the wavelength of the input light L1, and may have a particle size of about 50nm to 3000nm, the scattering of light may be suppressed by reducing the particle size of the dielectric material, and the particle size of the inducer material may be not more than 1000nm, or not more than 100nm in consideration of the scattering of light, the dielectric material may be a powder of the electro-optical crystal 101, the dielectric material does not have the pockels effect, and as an example, the ratio of the dielectric material to the adhesive material and the dielectric material in the mixture of the adhesive material and the dielectric material may be not more than 50%.

In addition, the charge injection inhibiting layer 121 may be made of SiO₂、HfO₂、BaTiO₃、BST((Ba，Sr)TiO₃)、STO(SrTiO₃)、SrTa₂O₆、Sr₂Ta₂O₇、ZnO、Ta₂O₅、SiO₂、PZT(Pb(Zr，Ti)O₃、PZTN(Pb(Zr，Ti)Nb₂O₈、PLZT((Pb，La)(Zr，Ti)O₃、SBT(SrBi₂Ta₂O₉)、SBTN(SrBi₂(Ta，Nb)₂O₉、BTO(Bi₄Ti₃O₁₂) And the like dielectric material.

The intermediate layer 120 is formed on the input surface 101 a. In the present embodiment, the intermediate layer 120 is in contact with the electric-charge-injection inhibiting layer 121, and is uniformly formed on the input surface 101a to an edge on one side of the electric-charge-injection inhibiting layer 121. The height of the intermediate layer 120 may be, for example, the same as the height of the charge injection inhibiting layer 121. The intermediate layer 120 may be formed of, for example, the same adhesive material as that constituting the charge injection inhibiting layer 121. The intermediate layer 120 may be a mixture of the same adhesive material and dielectric material as the charge injection inhibiting layer 121. The intermediate layer 120 may be made of SiO₂、HfO₂And the like.

The insulating portion 105 is formed on the intermediate layer 120. In the present embodiment, the insulating portion 105 is in contact with the transparent electrode 103, and is formed uniformly on the intermediate layer 120 to the end edge on one side of the transparent electrode 103. The insulating portion 105 is formed to have a height lower than that of the transparent electrode 103, for example. The insulating part 105 is, for exampleFrom SiO₂、HfO₂And the like. The insulating portion 105 is provided with a connection electrode 104. That is, the insulating portion 105 is disposed between the intermediate layer 120 and the connection electrode 104. Accordingly, the insulating portion 105 has a thickness to which most of the electric field generated by the connection electrode 104 is applied regardless of the electric field applied to the electro-optical crystal 101. Further, in the case where the intermediate layer 120 and the insulating portion 105 are formed of the same material, the intermediate layer 120 and the insulating portion 105 can be integrally formed.

The connection electrode 104 is electrically connected to the transparent electrode 103, the connection electrode 104 has a thin wire-shaped lead portion 104a having one end electrically connected to the transparent electrode 103 and a rectangular main body portion 104b electrically connected to the other end of the lead portion 104a in a plan view, for example, the main body portion 104b has a larger area than the transparent electrode 103, and the main body portion 104b extends to the periphery of the input surface 101a, for example, in the present embodiment, one side 104c of the main body portion 104b formed in a rectangular shape coincides with the periphery of the input surface 101a of the electro-optical crystal 101, the connection electrode 104 may be formed of a transparent material such as ITO as in the same manner as the transparent electrode 103, and the connection electrode 104 may be formed of a conductive material other than the transparent material that does not transmit the input light L1, for example, the connection electrode 104 may be formed by depositing ITO on the insulating portion 105 using a mask pattern.

As shown in fig. 2 (c), the light output unit 106 includes: a transparent electrode (second electrode) 107, an electric-charge-injection inhibiting layer 123, an intermediate layer 122, a connection electrode (fourth electrode) 108, and an insulating portion 109.

The transparent electrode 107 is disposed on the back surface 101b side of the electro-optical crystal 101, the transparent electrode 107 is formed of, for example, ITO in the same manner as the transparent electrode 103, and transmits input light L1, that is, input light L1 which is input into the electro-optical crystal 101 and is phase-modulated or delay-modulated can be output from the transparent electrode 107 as modulated light L2. in the present embodiment, the transparent electrode 107 is formed, for example, in a rectangular shape in plan view, partially covering the back surface 101 b. in addition, the area (μm) of the transparent electrode 107 is set²) When the thickness of the electro-optical crystal 101 in the electric field application direction is d (μm), it may be 25d²The following. The transparent electrode 107 is formed as a single body substantially in the center of the rear surface 101bIs spaced from the periphery of the back surface 101 b. In addition, the transparent electrode 107 is formed to have a larger area than the transparent electrode 103 in a plan view. In addition, the center of the transparent electrode 107 and the center of the transparent electrode 103 substantially coincide in the optical axis direction. Therefore, when viewed in the optical axis direction, the entire transparent electrode 103 converges on the inside of the transparent electrode 107.

The electric-charge-injection inhibiting layer 123 is formed between the transparent electrode 107 and the back surface 101 b. The charge injection inhibiting layer 123 is, for example, the same size as the transparent electrode 107, and is formed in a rectangular shape in a plan view. The electric-charge-injection inhibiting layer 123 can be formed of the same material as the electric-charge-injection inhibiting layer 121, for example.

The intermediate layer 122 is formed on the back surface 101 b. In the present embodiment, the intermediate layer 122 is in contact with the electric-charge-injection inhibiting layer 123, and is uniformly formed on the rear surface 101b to an edge on one side of the electric-charge-injection inhibiting layer 123. The height of the intermediate layer 122 may be, for example, the same as the height of the charge injection inhibiting layer 123. The intermediate layer 122 can be formed of the same material as the intermediate layer 120, for example.

The insulating portion 109 is formed on the intermediate layer 122. In the present embodiment, the insulating portion 109 is in contact with the transparent electrode 107, and is formed uniformly on the intermediate layer 122 to the edge on one side of the transparent electrode 107. The insulating portion 109 is formed to have a height lower than that of the transparent electrode 107, for example. The insulating portion 109 is made of, for example, SiO₂Or HfO₂And the like. The insulating portion 109 is provided with a connection electrode 108. That is, the insulating portion 109 is disposed between the intermediate layer 122 and the connection electrode 108. Thereby, the insulating portion 109 insulates the electric field generated by the connection electrode 108.

The connection electrode 108 is electrically connected to the transparent electrode 107. the connection electrode 108 has a thin wire-shaped lead portion 108a having one end electrically connected to the transparent electrode 107 and a rectangular main body portion 108b electrically connected to the other end of the lead portion 108a in a plan view, for example, the area of the main body portion 108b is larger than that of the transparent electrode 107. the main body portion 108b extends to the periphery of the rear surface 101 b. in the present embodiment, one side 108c of the main body portion 108b formed in a rectangular shape is coincident with the periphery of the rear surface 101b of the electro-optical crystal 101. in addition, one side 108c of the main body portion 108b may not be coincident with the periphery of the rear surface 101b of the electro-optical crystal 101. the connection electrode 108 may be formed of a transparent material such as ITO in the same manner as the transparent electrode 107. in addition to the transparent material, it may be formed of a conductive material that does not transmit the input light L1.

The drive circuit 110 applies an electric field between the transparent electrode 103 and the transparent electrode 107. In this embodiment, the driving circuit 110 is electrically connected to the connection electrode 104 and the connection electrode 108. The drive circuit 110 inputs an electric signal to the connection electrode 104 and the connection electrode 108, and applies an electric field between the transparent electrode 103 and the transparent electrode 107. Such a drive circuit 110 is controlled by the control section 19.

The drive circuit 110 inputs an electric signal between the transparent electrode 103 and the transparent electrode 107. Thereby, an electric field is applied to the electro-optical crystal 101 and the charge injection inhibiting layers 121 and 123 disposed between the transparent electrode 103 and the transparent electrode 107. In this case, the voltage applied by the driving circuit 110 is distributed to the electro-optical crystal 101 and the electric-charge-injection inhibiting layers 121 and 123. Therefore, the voltage ratio R between the voltage applied between the transparent electrode 103 and the transparent electrode 107 and the voltage applied to the electro-optical crystal 101 is such that the voltage applied to the electro-optical crystal 101 is V_xtlThe voltage applied to the charge injection inhibiting layers 121 and 123 is set to V_adThe relative dielectric constant of the electro-optical crystal 101 is set to_xtlD represents a thickness from the input surface 101a to the back surface 101b of the electro-optical crystal 101_xtlThe relative dielectric constant of the charge injection inhibiting layers 121 and 123 is set to_adD represents the total thickness of the charge injection inhibiting layers 121 and 123_adThe formula (1) is as follows. Further, for convenience of explanation, the electric-charge-injection inhibiting layer 121 and the electric-charge-injection inhibiting layer 123 are formed of materials having the same relative dielectric constant.

[ number 1]

Thus, the voltage applied to the electro-optical crystal 101 depends on the relative dielectric constant of the charge injection inhibiting layers 121 and 123_adAnd thickness d_adThe optical modulator 100 in this embodiment has, for example, a modulation capability of outputting modulated light L2 that modulates input light L1 at one wavelength, in this case, the relative dielectric constant of the charge injection suppression layers 121 and 123_adThe calculation is as follows. First, the maximum voltage of the applied voltage generated by the drive circuit 110 is set to V_smax. In addition, when V is to be_xtlApplied to an electro-optic crystal 101 to apply V_adWhen applied to the charge injection inhibiting layers 121, 123, a wavelength modulated light L2 is output, because of V at this time_xtl＜V_xtl+V_ad≦V_smaxIs established, so will be V_xtlAnd V_smaxV of voltage ratio of_xtl/V_smaxWhen Rs is set, the voltage ratio R and the voltage ratio R_sIn this case, a voltage sufficient for phase-modulating the input light L1 by 2 π radians can be applied to the electro-optical crystal 101.

R_s＜R…(2)

Then, according to the formulas (1) and (2), the relative dielectric constants of the electric-charge-injection inhibiting layers 121 and 123 are set_adAnd a thickness d_adSatisfies the following formula (3).

[ number 2]

From this equation (3), the relative dielectric constant of the charge injection inhibiting layers 121 and 123 is determined. That is, if equation (3) is modified to an equation relating to the relative dielectric constant of the charge injection inhibiting layers 121 and 123, equation (4) below is derived.

[ number 3]

The relative dielectric constant of the charge injection inhibiting layers 121 and 123 satisfies formula (4), and an electric field sufficient to modulate one wavelength of the input light L1 can be applied to the electro-optical crystal.

The relative dielectric constant ad of the charge injection inhibiting layers 121 and 123 and the thickness d of the charge injection inhibiting layers 121 and 123 are used_adRelative dielectric constant of the electro-optic crystal 101_xtlAnd the thickness d of the electro-optic crystal 101_xtlWhen the parameter m represented by the following formula (5) is defined, the parameter m preferably satisfies m > 0.3. In addition, the parameter m more preferably satisfies m > 3.

[ number 4]

According to the optical modulator 100 described above, the input light L1 is transmitted through the transparent electrode 103 of the light input unit 102 and input to the input surface 101a of the perovskite-type electro-optical crystal 101, and the input light L1 is transmitted through the light output unit 106 disposed on the back surface 101b of the electro-optical crystal 101 and output, at this time, an electric field is applied between the transparent electrode 103 disposed on the light input unit 102 and the transparent electrode 107 disposed on the light output unit 106, whereby an electric field can be applied to the electro-optical crystal 101 having a high relative permittivity and the input light L1 can be modulated, and in the optical modulator 100, the transparent electrode 103 partially covers the input surface 101a, and the area (μm) of the transparent electrode 103 (μm)²) In the case where the thickness of the electro-optical crystal 101 in the electric field application direction is d (μm), it is preferably 25d²The following. In addition, the transparent electrode 107 partially covers the rear surface 101 b. Area (μm) of the transparent electrode 107²) When the thickness of the electro-optical crystal 101 in the electric field application direction is d (μm), it may be 25d²The following. In this case, the inverse piezoelectric effect or the electrostrictive effect occurs in a portion where the transparent electrode 103 and the transparent electrode 107 face each other, but the inverse piezoelectric effect or the electrostrictive effect does not occur in the periphery thereof. Therefore, the periphery of the portion where the transparent electrode 103 and the transparent electrode 107 oppose each other functions as a damper. Thereby, the input surface 101a is covered with the electrodeAs compared with the case of the entire rear surface 101b, the reverse piezoelectric effect or the electrostrictive effect can be suppressed, and the occurrence of resonance or the like can be suppressed. Further, since the charge injection inhibiting layer for inhibiting injection of charge into the electro-optical crystal is formed, the behavior of electrons in the electro-optical crystal can be stabilized. Therefore, stable optical modulation can be performed.

In addition, since the area of the transparent electrode 103 is smaller than the area of the transparent electrode 107, the transparent electrode 103 and the transparent electrode 107 can be easily positioned.

The light input unit 102 includes a connection electrode 104 electrically connected to the transparent electrode 103, and an insulating unit 105 for shielding an electric field generated by the connection electrode 104. Further, the drive circuit 110 applies an electric field between the transparent electrode 103 and the transparent electrode 107 via the connection electrode 104. Since the connection electrode 104 is provided for connection to the drive circuit 110 in this manner, the size, position, and the like of the transparent electrode 103 can be freely designed. In this case, the insulating portion 105 can suppress the influence of the electric field generated by the connection electrode 104 on the electro-optical crystal 101. Similarly, the size, position, and the like of the transparent electrode 107 can be freely designed in the light output section 106. Further, the influence of the electric field generated by the connection electrode 108 on the electro-optical crystal 101 can be suppressed.

Further, since the temperature control element P for controlling the temperature of the electro-optical crystal 101 is provided, the temperature of the electro-optical crystal 101 can be kept constant. This makes it possible to stabilize the modulation accuracy. The temperature control by the temperature control element P may be performed not only for the electro-optical crystal 101 but also for the entire optical modulator 100.

[ second embodiment ]

The optical modulator 200 of the present embodiment is different from the optical modulator 100 of the first embodiment in that the light input portion 202 has a light reducing portion. Hereinafter, differences from the first embodiment will be mainly described, and the same elements and components will be denoted by the same reference numerals, and detailed description thereof will be omitted.

Fig. 4 is a schematic diagram of the optical modulator 200. The optical modulator 200 includes: electro-optical crystal 101, light input unit 202, light output unit 106, and driving circuit 110. Fig. 4 (a) shows a cross section of the electro-optical crystal 101, the light input unit 202, and the light output unit 106 of the optical modulator 200. Fig. 2 (b) is a view of the optical modulator 200 viewed from the light input section 202 side.

As shown in fig. 4, the light input section 202 includes: a transparent electrode 103, a connection electrode 104, an insulating portion 105, an electric-charge-injection inhibiting layer 121, an intermediate layer 120, an intermediate layer 124, and a light-reducing layer 205.

The intermediate layer 124 is formed on the input surface 101a except for the portion where the electric-charge-injection inhibiting layer 121 (transparent electrode 103) and the intermediate layer 120 (insulating portion 105) are formed. That is, the entire surface of the input surface 101a is covered with the electric-charge-injection inhibiting layer 121, the intermediate layer 120, and the intermediate layer 124. The material forming the intermediate layer 124 may also be, for example, the same as the material forming the intermediate layer 120.

The light reducing layer 205 is formed on the entire surface of the intermediate layer 124, the light reducing layer 205 suppresses transmission of the input light L1 in the electro-optical crystal 101, and the light reducing layer is formed of a material such as a black resist in which carbon is dispersed in an epoxy-based UV curable resin.

In the present embodiment, the insulating portion 105 is formed of a material that does not transmit the input light L1, and examples of such a material include a black resist in which carbon is dispersed in an epoxy-based UV curable resin, and the like, and thus, the input surface 101a is covered with the light reduction layer 205 and the insulating portion 105 around the transparent electrode 103, and the light reduction layer 205 and the insulating portion 105 reduce light input to the input surface 101a from a portion other than the transparent electrode 103. in other words, the light reduction portion 207 is formed of the light reduction layer 205 and the insulating portion 105. by providing such a light reduction portion 207, it is possible to suppress interference of the input light L1 with other light in the electro-optical crystal 101, and the like, and the light reduction portion 207 may be any of a reflection layer formed of a layer that reflects light, an absorption layer formed of a layer that absorbs light, and a shielding layer formed of a layer that shields light, and when the light reduction layer 205 and the insulating portion 105 are formed of the same material, the light reduction layer 205 and the insulating portion 105 may be integrally formed.

[ third embodiment ]

In the optical modulator 300 of the present embodiment, the structure of the light output section 306 is different from that of the optical modulator 100 of the first embodiment. Hereinafter, differences from the first embodiment will be mainly described, and the same elements and components will be denoted by the same reference numerals, and detailed description thereof will be omitted.

Fig. 5 is a schematic diagram of the optical modulator 300. The optical modulator 300 includes: electro-optical crystal 101, light input unit 102, light output unit 306, and driving circuit 110. In fig. 5. The electro-optical crystal 101, the light input unit 102, and the light output unit 306 of the optical modulator 300 are shown as cross-sections.

The light output section 306 includes a transparent electrode (second electrode) 307 and an electric charge injection inhibiting layer 323, the transparent electrode 307 is disposed on the back surface 101b side of the electro-optical crystal 101, the transparent electrode 307 is formed of, for example, ITO in the same manner as the transparent electrode 103, and transmits input light L1, that is, input light L1 which is input into the electro-optical crystal 101 and is phase-modulated or delay-modulated can be output from the transparent electrode 307 as modulated light L2, and in the present embodiment, the transparent electrode 307 is formed on the entire back surface 101b side.

The electric-charge-injection inhibiting layer 323 is formed between the transparent electrode 307 and the back surface 101 b. That is, the electric-charge-injection inhibiting layer 323 is formed on the entire surface of the back surface 101 b. The electric-charge-injection inhibiting layer 323 can be formed of the same material as the electric-charge-injection inhibiting layer 123, for example.

The drive circuit 110 is electrically connected to the connection electrode 104 and the transparent electrode 307, and applies an electric field between the transparent electrode 103 and the transparent electrode 307.

[ fourth embodiment ]

The optical modulator 400 of the present embodiment is different from the optical modulator 300 of the third embodiment in that a light input unit 202 is provided instead of the light input unit 102. Hereinafter, differences from the third embodiment will be mainly described, and the same elements and components are denoted by the same reference numerals, and detailed description thereof will be omitted.

Fig. 6 is a schematic diagram of the optical modulator 400. The optical modulator 400 includes: electro-optical crystal 101, light input unit 202, light output unit 306, and driving circuit 110. Fig. 6 shows the electro-optical crystal 101, the light input unit 202, and the light output unit 306 of the optical modulator 400 as cross-sections.

As shown in fig. 6, the light input portion 202 includes the transparent electrode 103, the connection electrode 104, the insulating portion 105, the electric-charge-injection inhibiting layer 121, the intermediate layer 120, the intermediate layer 124, and the light reducing portion 205, and thus, the light reducing portion 207 is constituted by the light reducing layer 205 and the insulating portion 105, as in the second embodiment, thereby making it possible to inhibit input of the input light L1 to the input surface 101a from the outside of the transparent electrode 103, and the light reducing portion 207 may be any of a reflective layer formed of a layer that reflects light, an absorbing layer formed of a layer that absorbs light, and a shielding layer formed of a layer that shields light.

[ fifth embodiment ]

In the optical modulator 500 of the present embodiment, the shape of the electro-optical crystal 501 is different from that of the optical modulator 100 of the first embodiment. Hereinafter, differences from the first embodiment will be mainly described, and the same elements and components will be denoted by the same reference numerals, and detailed description thereof will be omitted.

Fig. 7 is a schematic diagram of the optical modulator 500. The optical modulator 500 includes: electro-optical crystal 501, light input unit 102, light output unit 106, and driving circuit 110. Fig. 7 (a) shows a cross section of the electro-optical crystal 501, the light input unit 102, and the light output unit 106 of the optical modulator 500. Fig. 7 (b) is a view of the optical modulator 500 from the light input unit 102 side, and fig. 7 (c) is a view of the optical modulator 500 from the light output unit 106 side.

As shown in fig. 7, the electro-optical crystal 501 is formed in a plate shape having an input surface 501a to which input light L1 is input and a back surface 501b opposite to the input surface 501a, and the electro-optical crystal 501 is the same material as the electro-optical crystal 101 of the first embodiment, and is, for example, a KTN crystal.

In the present embodiment, the shape of the light input section 102 and the light output section 106 is the same as that of the first embodiment, whereas the shape of the electro-optical crystal 501 is formed more compactly than the electro-optical crystal 101 of the first embodiment. Thus, the transparent electrodes 103 and 107 are respectively arranged offset to one side (lower side in fig. 7 (b) and (c)) from the center of the input surface 101a side and the back surface 101b side. In the illustrated example, the periphery of the transparent electrode 103 is spaced apart from the periphery of the input surface 501 a. On the other hand, one side 107a of the transparent electrode 107 formed in a rectangular shape coincides with the periphery of the rear surface 101 b.

[ sixth embodiment ]

The optical modulator 600 of the present embodiment is different from the optical modulator 100 of the first embodiment in the configuration of the light input section 602 and the light output section 606. Hereinafter, differences from the first embodiment will be mainly described, and the same elements and components will be denoted by the same reference numerals, and detailed description thereof will be omitted.

Fig. 8 is a schematic diagram of the optical modulator 600. The optical modulator 600 includes: electro-optical crystal 101, light input section 602, light output section 606, and driving circuit 110. In fig. 8, the electro-optical crystal 101, the light input unit 602, and the light output unit 606 of the optical modulator 600 are shown as cross-sections.

As shown in fig. 8, the light input section 602 includes: the transparent electrode 103, the charge injection inhibiting layer 121, the intermediate layer 620, the insulating portion 605, and the transparent electrode 604 for connection. The intermediate layer 620 is formed on the entire input surface 101a except for the position where the electric-charge-injection inhibiting layer 121 is formed. The material forming the intermediate layer 620 may also be the same as the material forming the intermediate layer 120.

The insulating portion 605 is formed on the entire surface of the intermediate layer 620. The insulating part 605 is made of, for example, SiO₂Or HfO₂The insulating portion 605 may also have a property of not transmitting the input light L1, in which case the insulating portion 605 may function as a light reducing portion, and in the present embodiment, the height of the insulating portion 605 is formed to be substantially the same as the height of the transparent electrode 103.

The transparent electrode 604 for connection is formed on the entire surface of the transparent electrode 103 and the insulating portion 605, whereby the transparent electrode 604 for connection is electrically connected to the transparent electrode 103, and the input light L1 is input from the transparent electrode 604 for connection to the transparent electrode 103, and therefore, the transparent electrode 604 for connection is formed of a material that transmits the input light L1.

The light output unit 606 includes: the transparent electrode 107, the electric-charge-injection inhibiting layer 123, the intermediate layer 622, the insulating portion 609, and the transparent electrode 608 for connection. The intermediate layer 622 is formed on the entire surface of the back surface 101b except for the position where the electric-charge-injection inhibiting layer 123 is formed. The material forming the intermediate layer 622 may also be the same as the material forming the intermediate layer 120.

The insulating portion 609 is formed over the entire surface of the intermediate layer 620. The insulating portion 609 is made of, for example, SiO₂Or HfO₂The insulating portion 609 may have a property of not transmitting the input light L1, in this case, the insulating portion 609 may function as a light reducing portion, and in the present embodiment, the height of the insulating portion 609 is formed to be substantially the same as the height of the transparent electrode 107.

The transparent electrode 608 for connection is formed on the entire surface of the transparent electrode 107 and the insulating portion 609, whereby the transparent electrode 608 for connection is electrically connected to the transparent electrode 107, and the modulated light L2 is output from the transparent electrode 107 via the transparent electrode 608 for connection, and therefore, the transparent electrode 608 for connection is formed of a material that transmits the modulated light L2, and for example, the transparent electrode 608 for connection may be formed of ITO in the same manner as the transparent electrode 107.

The drive circuit 110 is electrically connected to the transparent electrode 604 for connection and the transparent electrode 608 for connection, and applies an electric field between the transparent electrode 103 and the transparent electrode 107.

[ seventh embodiment ]

The optical modulator 700 of the present embodiment is different from the optical modulator 600 of the sixth embodiment in that the electro-optical crystal 101 is supported by the transparent substrate 713. Hereinafter, differences from the sixth embodiment will be mainly described, and the same elements and components will be denoted by the same reference numerals, and detailed description thereof will be omitted.

Fig. 9 is a schematic diagram of the optical modulator 700. The optical modulator 700 includes: electro-optical crystal 101, light input section 602, light output section 606, and driving circuit 110. Fig. 9 shows a cross section of the electro-optical crystal 101, the light input unit 602, and the light output unit 606 of the optical modulator 700. The thickness of the electro-optical crystal 101 in the optical axis direction in the present embodiment can be set to, for example, 50 μm or less.

The back surface 101b side of the electro-optic crystal 101 is supported by a transparent substrate 713 through which modulated light L2 passes, the transparent substrate 713 is formed in a flat plate shape from a material such as glass, quartz, plastic, etc., the transparent substrate 713 has an output surface (second surface) 713b from which modulated light L2 is output, an input surface (first surface) 713a which is a surface opposite to the output surface 713b and which faces the light output portion 606 formed in the electro-optic crystal 101, a transparent electrode 715 formed from, for example, ITO is formed on the input surface 713a of the transparent substrate 713, the transparent electrode 715 is formed on the entire input surface 713a, and the transparent electrode 715 can be formed by vapor-depositing ITO on the input surface 713a of the transparent substrate 713.

Transparent electrodes 608 for connection formed on the electro-optical crystal 101 and transparent electrodes 715 formed on the transparent substrate 713 are bonded to each other by a transparent adhesive layer 717, the transparent adhesive layer 717 is formed of, for example, an epoxy adhesive and transmits modulated light L2, conductive members 717a such as metal balls are disposed in the transparent adhesive layer 717, the conductive members 717a are in contact with both the transparent electrodes 608 for connection and the transparent electrodes 715, the transparent electrodes 608 for connection and the transparent electrodes 715 are electrically connected to each other, and the conductive members 717a are disposed at the four corners of the transparent adhesive layer 717 in plan view, for example.

In this embodiment, the size of the transparent substrate 713 on the input surface 713a side in a plan view is formed larger than the back surface 101b of the electro-optical crystal 101. Therefore, in a state where the electro-optical crystal 101 is supported by the transparent substrate 713, a part of the transparent electrode 715 formed on the transparent substrate 713 becomes an exposed portion 715a exposed to the outside. The drive circuit 110 is electrically connected to the exposed portion 715a and the connection transparent electrode 604. That is, the driving circuit 110 is electrically connected to the transparent electrode 107 via the transparent electrode 715, the conductive member 717a, and the transparent electrode 608 for connection, and is electrically connected to the transparent electrode 103 via the transparent electrode 604 for connection. Thereby, the drive circuit 110 can apply an electric field between the transparent electrode 103 and the transparent electrode 107.

In the optical modulator 700, the thickness of the electro-optical crystal 101 in the optical axis direction is made thin, whereby phase modulation and retardation modulation can be performed more favorably. When the electro-optical crystal 101 is formed thin in this manner, the electro-optical crystal 101 may be damaged by an impact from the outside. In this embodiment, the electro-optical crystal 101 is supported by the transparent substrate 713, thereby protecting the electro-optical crystal 101 from external impact or the like.

[ eighth embodiment ]

The optical modulator 800 of the present embodiment is different from the optical modulator 100 of the first embodiment in that it is a reflective optical modulator, and when a reflective optical modulator is used, it is possible to use an optical element such as a beam splitter that guides the input light L1 to the optical modulator and guides the modulated light L2 modulated by the optical modulator to the first optical system 14.

Fig. 10 is a schematic diagram showing an optical modulator 800, the optical modulator 800 is a reflective optical modulator that modulates input light L1 and outputs modulated light L2, and as shown in fig. 10, includes an electro-optical crystal 101, a light input/output section (first optical element) 802, a light reflection section (second optical element) 806, and a drive circuit 110, and in fig. 10, the electro-optical crystal 101, the light input/output section 802, and the light reflection section 806 of the optical modulator 800 are shown as cross-sections, and the thickness of the electro-optical crystal 101 in the optical axis direction in the present embodiment can be set to, for example, 50 μm or less.

The back surface 101b side of the electro-optical crystal 101 is supported by the substrate 813. The substrate 813 is formed in a flat plate shape. The substrate 813 has: a first surface 813a facing the light reflection unit 806 joined to the electro-optical crystal 101, and a second surface 813b which is the surface opposite to the first surface 813 a. An electrode 815 is formed on the first surface 813a of the substrate 813. The electrode 815 is formed on the entire surface of the first surface 813 a.

The optical input/output unit 802 includes: a transparent electrode (first electrode) 803, an electric-charge-injection inhibiting layer 121, an intermediate layer 620, a connection electrode (third electrode) 104, an insulating portion 105, and a light-reducing layer 205. Transparent electricityThe transparent electrode 803 is formed of, for example, ITO and transmits input light L1, that is, input light L1, to the electro-optic crystal 101 through the transparent electrode 803, the transparent electrode 803 is formed at one central position on the input surface 101a side, and partially covers the input surface 101a and the area (μm) of the transparent electrode 803²) When the thickness of the electro-optical crystal 101 in the electric field application direction is d (μm), it may be 25d²The following. The transparent electrode 803 is formed in a rectangular shape in plan view, for example. That is, the transparent electrode 803 is spaced apart from the periphery of the input surface 101 a. Such a transparent electrode 803 can be formed by, for example, depositing ITO on the input surface 101a of the electro-optical crystal 101 using a mask pattern.

The electric-charge-injection inhibiting layer 121 is formed between the transparent electrode 803 and the input surface 101 a. The charge injection inhibiting layer 121 has the same size as the transparent electrode 803, for example, and is formed in a rectangular shape in a plan view.

The light reflector 806 includes: a transparent electrode (second electrode) 807, an electric-charge-injection inhibiting layer 123, an intermediate layer 622, a connection electrode (fourth electrode) 108, an insulating portion 109, and a dielectric multilayer film 809. The transparent electrode 807 is disposed on the back surface 101b side of the electro-optical crystal 101. In this embodiment, the transparent electrode 807 is formed at one position in the center of the rear surface 101b side, and partially covers the rear surface 101 b. Area (μm) of the transparent electrode 807²) When the thickness of the electro-optical crystal 101 in the electric field application direction is d (μm unit), it may be 25d²The transparent electrode 807 is formed in a rectangular shape in plan view, that is, the transparent electrode 807 is separated from the periphery of the back surface 101b, the transparent electrode 807 is formed of, for example, ITO, and transmits input light L1, that is, input light L1 which is input into the electro-optical crystal 101 and is phase-modulated or delay-modulated can be transmitted as modulated light L2 through the transparent electrode 807, in the present embodiment, a dielectric multilayer film 809 which can efficiently reflect light is provided on the surface of the connection electrode 108 provided on the transparent electrode 807, in this case, the connection electrode 108 is a transparent electrode, the connection electrode 108 and the dielectric multilayer film 809 reflect the modulated light L2 transmitted through the transparent electrode 807 toward the transparent electrode 803 formed on the input surface 101a, and the dielectric layer 809 reflects the modulated light L transmitted through the transparent electrode 807The multilayer film 809 can be formed by, for example, depositing a high refractive index material (Ta) on the surface of the transparent electrode 807₂O₅) And a low refractive index Substance (SiO)₂) And the like, and the modulated light L2 can be reflected by using the connection electrode 108 as a reflection electrode, in which case the dielectric multilayer film 809 is not required.

The electric-charge-injection inhibiting layer 123 is formed between the transparent electrode 807 and the back surface 101 b. The charge injection inhibiting layer 123 is, for example, the same size as the transparent electrode 807, and is formed in a rectangular shape in a plan view.

The connection electrode 108 formed on the electro-optical crystal 101 and the electrode 815 formed on the substrate 813 are bonded to each other by an adhesive layer 817. The adhesive layer 817 is formed of, for example, an epoxy adhesive. A conductive member 817a such as a metal ball is disposed in the adhesive layer 817. The conductive member 817a is in contact with both the connection electrode 108 and the electrode 815, and electrically connects the connection electrode 108 and the electrode 815 to each other. For example, the conductive members 817a are arranged at the four corners of the adhesive layer 817 in plan view. The electrode 815 has an exposed portion 815a, a portion of which is exposed to the outside. The drive circuit 110 is electrically connected to the exposed portion 815a and the connection electrode 104.

In addition, the area of the transparent electrode 807 is formed smaller than the transparent electrode 803 when viewed from the optical axis direction, and thus the center of the transparent electrode 807 and the center of the transparent electrode 803 are substantially aligned in the optical axis direction, in this case, for example, even when the input light L1 is inclined with respect to the reflection surface of the dielectric multilayer film 809, the reflected modulated light L2 easily passes through the transparent electrode 803, and as shown in fig. 10, even when the beam waist is aligned with the reflection surface of the dielectric multilayer film 809, the input light L1 and the modulated light L2 easily pass through the transparent electrode 803, and in this embodiment, the electro-optical crystal 101 is supported by the substrate 813, and the electro-optical crystal 101 is protected from external impact and the like, as in the seventh embodiment.

[ ninth embodiment ]

The optical modulator 900 of the present embodiment is different from the optical modulator 100 of the first embodiment in that the light output section 106 is changed to include the light output section 906. Hereinafter, differences from the first embodiment will be mainly described, and the same elements and components will be denoted by the same reference numerals, and detailed description thereof will be omitted.

Fig. 11 is a schematic diagram of the optical modulator 900. The optical modulator 900 includes: electro-optical crystal 101, light input unit 102, light output unit 906, and driving circuit 110. Fig. 11 (a) shows a cross section of the electro-optical crystal 101, the light input unit 102, and the light output unit 906 of the optical modulator 900. Fig. 11 (b) is a view of the optical modulator 900 from the light input unit 102 side, and fig. 11 (c) is a view of the optical modulator 900 from the light output unit 906 side.

The light output section 906 includes: a transparent electrode 107, an electric-charge-injection inhibiting layer 123, a connection electrode 908, an intermediate layer 922, and an insulating portion 909. The connection electrode 908 is connected to the transparent electrode 107 and the drive circuit 110, similarly to the connection electrode 108 in the first embodiment. The intermediate layer 922 is disposed on the rear surface 101b in the same manner as the intermediate layer 122 in the first embodiment. The insulating portion 909 is formed on the intermediate layer 922 in the same manner as the insulating portion 109 in the first embodiment, and is disposed between the intermediate layer 922 and the connection electrode 908.

The positions of the electrodes 104, the insulating portions 105, and the intermediate layers 120 on the input surface 101a and the positions of the electrodes 908, the insulating portions 909, and the intermediate layers 122 on the back surface 101b are opposite to each other with respect to the transparent electrodes 103 and the transparent electrodes 107, when viewed along the optical axis. Therefore, the connection electrode 104, the insulating portion 105, and the intermediate layer 120, and the connection electrode 908, the insulating portion 909, and the intermediate layer 122 are arranged so as to be shifted from each other when viewed in the direction along the optical axis, and so as not to overlap each other with the electro-optical crystal 101 interposed therebetween. According to the optical modulator 900, the effect of the insulating portion can be further improved. Further, the insulating portions 105, 909 are not necessarily required.

[ tenth embodiment ]

The optical modulator 1000 of the present embodiment is different from the optical modulator 100 of the first embodiment in that it further includes transparent substrates 125 and 126. Hereinafter, differences from the first embodiment will be mainly described, and the same elements and components will be denoted by the same reference numerals, and detailed description thereof will be omitted.

Fig. 12 is a schematic diagram of the optical modulator 1000. The optical modulator 1000 includes: an electro-optical crystal 101, a light input unit 102, a light output unit 106, a drive circuit 110, a transparent substrate 125, and a transparent substrate 126.

The transparent substrate 125 is formed in a flat plate shape from a material such as glass, quartz, or plastic, for example, the transparent substrate 125 has an input surface 125a to which input light L1 is input, an output surface 125b which is a surface opposite to the input surface 125a and faces the input surface 101a of the electro-optical crystal 101, a transparent electrode 103 is formed on the output surface 125b, and a connection electrode 104 is formed, and the transparent substrate 125 protrudes from an edge of the electro-optical crystal 101 in a direction intersecting the optical axis direction, whereby in the present embodiment, a part of the connection electrode 104 formed on the transparent substrate 125 becomes an exposed portion 104d which is exposed to the outside, and the drive circuit 110 is electrically connected to the exposed portion 104 d.

The transparent substrate 126 is formed in a flat plate shape from a material such as glass, quartz, or plastic, for example, the transparent substrate 126 includes an output surface 126a for outputting modulated light L2, and an input surface 126b which is a surface opposite to the output surface 126a and faces the back surface 101b of the electro-optical crystal 101. the transparent substrate 126 has a transparent electrode 107 formed on the input surface 126b and a connection electrode 108 formed thereon. the transparent substrate 126 protrudes from the edge of the electro-optical crystal 101 in a direction intersecting the optical axis direction, and thus, in the present embodiment, a part of the connection electrode 108 formed on the transparent substrate 126 is an exposed portion 108d to the outside, and the drive circuit 110 is electrically connected to the exposed portion 108d, that is, the drive circuit 110 is electrically connected to the transparent electrode 103 via the connection electrode 104 and is electrically connected to the transparent electrode 107 via the connection electrode 108.

In the second to tenth embodiments described above, as in the first embodiment, it is possible to suppress the occurrence of resonance or the like and perform stable optical modulation.

The embodiments are described in detail above with reference to the drawings, but the specific configuration is not limited to the embodiments.

For example, in the above-described embodiment, the light observation device 1A including the light modulator is exemplified, but the present invention is not limited thereto, for example, the light modulator 100 may be mounted on the light irradiation device 1B, fig. 13 is a block diagram showing a configuration of the light irradiation device, the light irradiation device 1B includes the light source 11, the condenser lens 12, the light modulator 100, the first optical system 14, and the control unit including the computer 20 and the controller 21, and in this configuration, the modulated light L2 output from the light modulator 100 is irradiated to the sample S through the first optical system 14.

In the first to seventh embodiments, the ninth embodiment, and the tenth embodiment, the use example in which the input light L1 is input from the light input section and the modulated light L2 is output from the light output section is shown, but the present invention is not limited to this, for example, the input light L1 may be input from the light output section of the optical modulator and the modulated light L2 may be output from the light input section in such a use method, for example, the transparent electrode 103 corresponds to the second electrode and the transparent electrode 107 having a larger area than the second electrode corresponds to the first electrode, and in this case, for example, the light reduction section may be formed in the light output section 106 on the side where the input light L1 is input in the optical modulator 200.

In the eighth embodiment, the structure in which light is reflected by the dielectric multilayer film 809 formed on the surface of the transparent electrode 807 is illustrated, but the structure is not limited to this. For example, the transparent electrode 807 may be replaced with an electrode capable of reflecting light, so that the input light is reflected by the electrode. For example, the input light may also be reflected by an electrode formed of aluminum. According to this structure, a reflective layer or the like does not need to be provided on the second electrode side.

In addition, the structures in the above embodiments may be partially combined or replaced. For example, in the second to eighth embodiments, the temperature of the electro-optical crystal or the like may be controlled by the temperature control element P in the same manner as the electro-optical crystal 101 in the first embodiment.

Description of the symbols

1a … light observation device, 1B … light irradiation device, 100 … light modulator, 101 … electro-optic crystal, 101a … input surface, 101B … back surface, 102 … light input section (first optical element), 103 … transparent electrode (first electrode), 104 … connection electrode (third electrode), 105 … insulating section, 106 … light output section (second optical element), 107 … transparent electrode (second electrode), 110 … drive circuit, 207 … light reduction section, 809 … dielectric multilayer film, L1 … input light, L2 … modulated light, P … temperature control element.