阅读说明：本技术 一种基于亚波长光栅超表面的热控相位调制器 (Thermal control phase modulator based on sub-wavelength grating super-surface ) 是由 何赛灵 刘振超 郭庭彪 谭沁 董红光 于 2020-08-05 设计创作，主要内容包括：本发明涉及一种基于亚波长光栅超表面的热控相位调制器,包括第一层底层的透明介质基底、第二层金属薄膜层、第三层介质薄膜层、第四层介质光栅层、第五层高折射率介质光栅层、第六层热光介质层；所述的介质光栅层和高折射率介质光栅层为周期性光栅阵列,光栅周期同为p,光栅占空比同为q,厚度分别为t1和t2,其中t1<t2；所述的基于该亚波长光栅超表面结构的热控相位调制器存在一个高Q值共振峰,高Q峰处伴随着剧烈的相位突变,且相位突变曲线将随着外界折射率改变而发生漂移。基于本发明可实现高灵敏的热控相位调制,从而实现空间光调制器的功能,可用于光通信、显示与成像、光信号处理、自动驾驶、微波信号处理等领域。(The invention relates to a thermal control phase modulator based on a sub-wavelength grating super-surface, which comprises a first bottom layer of transparent medium substrate, a second metal film layer, a third medium film layer, a fourth medium grating layer, a fifth high-refractive-index medium grating layer and a sixth thermal-optical medium layer, wherein the first bottom layer of transparent medium substrate is a transparent substrate; the medium grating layer and the high-refractive-index medium grating layer are periodic grating arrays, the grating periods are the same as p, the grating duty ratios are the same as q, the thicknesses are t1 and t2 respectively, wherein t1 is less than t 2; the thermal control phase modulator based on the sub-wavelength grating super-surface structure has a high-Q-value resonant peak, severe phase jump is accompanied at the high-Q-value resonant peak, and a phase jump curve drifts along with the change of an external refractive index. The invention can realize high-sensitivity thermal control phase modulation, thereby realizing the function of a spatial light modulator, and can be used in the fields of optical communication, display and imaging, optical signal processing, automatic driving, microwave signal processing and the like.)

1. A thermal control phase modulator based on a sub-wavelength grating super-surface is characterized by comprising a first bottom layer of transparent medium substrate (1), a second metal film layer (2), a third medium film layer (3), a fourth medium grating layer (4), a fifth high-refractive-index medium grating layer (5) and a sixth thermal optical medium layer (6);

the medium grating layer (3) and the high-refractive-index medium grating layer (4) are periodic grating arrays, the grating periods are the same as p, the grating duty cycles are the same as q, and the thicknesses are t1 and t2 respectively, wherein t1 is less than t 2;

the thermal control phase modulator based on the sub-wavelength grating super-surface structure has a high-Q-value formant, the high-Q-value formant is accompanied by violent phase jump, and a phase jump curve drifts along with the change of an external refractive index; the working wavelength is adjusted by changing the grating parameters, and the working wavelength of the phase modulator is changed by changing the grating period p parameter, so that the phase modulator can be used for phase modulation in the range from visible light to near-infrared wave bands;

the thermo-optic medium layer (6) has a thermo-optic effect, and the phase of the working wavelength is regulated and controlled by controlling the temperature.

2. The thermal control phase modulator based on sub-wavelength grating super-surface according to claim 1,

a heating electrode array (7) is arranged between the transparent medium substrate (1) of the first bottom layer and the second metal thin film layer (2), or a heating electrode array (7) is arranged on the sixth thermo-optic medium layer (6), so that the phase of the unit pixel can be independently regulated and controlled, the heating electrode array (7) is made of transparent conductive materials or metal materials, the transparent conductive materials comprise indium tin oxide and graphene, and the metal materials comprise titanium, chromium and tungsten.

3. The sub-wavelength grating super-surface based thermal control phase modulator according to claim 1, wherein the transparent dielectric substrate (1) is a transparent material with a refractive index lower than 1.6, and comprises glass and plastic.

4. The sub-wavelength grating super-surface-based thermal control phase modulator according to claim 1, wherein the metal thin film layer (2) is made of a metal material with metal loss and metal high-reflectivity, and comprises Au, Ag, Al, Cu and Ti.

5. The sub-wavelength grating super-surface based thermal control phase modulator according to claim 1, wherein the material of the dielectric thin film layer (3) and the dielectric grating layer (4) comprises Si₃N₄、ZnO、SiO₂。

6. The sub-wavelength grating super-surface based thermal control phase modulator according to claim 1, wherein the high refractive index medium grating layer (5) is a medium material with refractive index greater than (2), and comprises TiO₂、ZrO₂、Ta₂O₅、Si。

7. The sub-wavelength grating super-surface based thermal control phase modulator according to claim 1, wherein the thermo-optic medium layer (6) is a material with thermo-optic effect, and comprises PDMS and liquid crystal.

Technical Field

The invention belongs to the field of optical phase modulation, and relates to a thermal control phase modulator based on a sub-wavelength grating super surface, which can be applied to the fields of optical communication, display and imaging, optical signal processing, automatic driving, microwave signal processing and the like.

Background

GMR (Guided-Mode Resonance) refers to a phenomenon in which an external field is coupled to a leaky Mode of a sub-wavelength grating waveguide to cause Resonance. The diffraction grating can be equivalent to a periodically modulated planar waveguide, when a guided wave mode supported by an external propagation wave and a sub-wavelength grating waveguide meets the wave vector matching, strong coupling can be generated, coupled energy is reflected or transmitted out through the periodic grating to form a sharp reflection or transmission resonant peak, and a severe phase abrupt change exists at the resonant peak, and the phase change can be changed along with the drift of the resonant peak. The MAGMR (Metal assisted guided-Mode Resonance) is to add a Metal film with a certain thickness on the bottom of a sub-wavelength grating on the basis of GMR, and a propagation Mode inside a waveguide can experience faster attenuation due to the loss property of a Metal-dielectric interface. As the wavelength moves away from resonance, the metal layer begins to exhibit the highly reflective nature of its metal, and incident light is reflected back. The MAGMR can provide sharper resonance peaks than GMR and more abrupt phase changes. Devices based on the GMR principle have been widely used in the fields of filters, optical modulators, optical switches, sensors, etc. The optical modulator is used as a core element and has important application in many occasions such as imaging and displaying, laser-assisted automatic driving, wave front shaping, holographic storage, optical tweezers and the like. Thus, there are many potential applications for implementing a phase modulator using the GMR principle.

However, the Q value of the current GMR and mamr based sensors is still low, and the resonance peak is not sharp enough, so that the phase jump is not sharp enough, which is not good for the application of high-sensitivity phase modulators.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a thermal control phase modulator based on a sub-wavelength grating super surface, which can realize high-sensitivity thermal control phase modulation, thereby realizing the functions of the phase modulator and a spatial light modulator and being used in the fields of optical communication, optical signal processing, microwave signal processing and the like.

A thermal control phase modulator based on a sub-wavelength grating super-surface comprises a first bottom layer of transparent medium substrate, a second metal film layer, a third medium film layer, a fourth medium grating layer, a fifth high-refractive-index medium grating layer and a sixth thermo-optic medium layer;

the medium grating layer and the high-refractive-index medium grating layer are periodic grating arrays, the grating periods are the same as p, the grating duty ratios are the same as q, the thicknesses are t1 and t2 respectively, wherein t1 is less than t 2;

the thermal control phase modulator based on the sub-wavelength grating super-surface structure has a high-Q-value formant, the high-Q-value formant is accompanied by violent phase jump, and a phase jump curve drifts along with the change of an external refractive index; the working wavelength is adjusted by changing the grating parameters, and the working wavelength of the phase modulator is changed by changing the grating period p parameter, so that the phase modulator can be used for phase modulation in the range from visible light to near-infrared wave bands;

the thermo-optic medium layer has a thermo-optic effect, and the phase of the working wavelength is regulated and controlled by controlling the temperature.

A heating electrode array is arranged between the transparent medium substrate of the first bottom layer and the second metal thin film layer, or a heating electrode array is arranged on the sixth thermo-optic medium layer, so that the phase of the unit pixel can be independently regulated and controlled, the heating electrode array is made of transparent conductive materials or metal materials, the transparent conductive materials comprise indium tin oxide and graphene, and the metal materials comprise titanium, chromium and tungsten.

The transparent medium substrate is made of transparent materials with the refractive index lower than 1.6 and comprises glass and plastics.

The metal thin film layer is made of metal materials with metal loss and metal high-reflection characteristics, and comprises Au, Ag, Al, Cu and Ti.

The medium thin film layer and the medium grating layer material comprise Si₃N₄、ZnO、SiO₂。

The high-refractive-index medium grating layer is made of a medium material with the refractive index larger than 2 and comprises TiO₂、ZrO₂、Ta₂O₅、Si。

The thermo-optic medium layer is made of materials with thermo-optic effect and comprises PDMS and liquid crystal.

The invention has the beneficial effects that:

the sub-wavelength grating super-surface chip has a very high Q value and a very violent phase mutation, is combined with a thermo-optic material with a good thermo-optic effect, and can be used for high-sensitivity thermal control phase modulation. Based on the chip structure, high-sensitivity thermal control phase modulation can be realized, so that the functions of a phase modulator and a spatial light modulator are realized, and the chip can be used in the fields of optical communication, optical signal processing, microwave signal processing and the like.

Drawings

Fig. 1 is a schematic structural diagram of a thermal control phase modulator based on a sub-wavelength grating super surface according to the present invention.

FIG. 2 is a reflection spectrum of a thermally controlled phase modulator of a sub-wavelength grating super-surface.

Fig. 3 is a PDMS based thermally controlled phase modulation profile.

Fig. 4 is a graph showing the variation of the operating wavelength of the thermally controlled phase modulator with the grating parameters.

Description of reference numerals:

1-transparent medium substrate, 2-metal thin film layer, 3-medium thin film layer, 4-medium grating layer, 5-high refractive index medium grating layer, 6-thermal optical medium layer and 7-heating electrode array.

Detailed Description

The invention is further elucidated with reference to the drawing.