阅读说明：本技术 一种宽谱段共光路3-d角镜消零干涉仪 (Wide-spectrum common-path 3-D angle mirror zero-eliminating interferometer ) 是由 魏儒义 张学敏 胡炳樑 王鹏冲 狄腊梅 于 2020-03-19 设计创作，主要内容包括：本发明公开了一种宽谱段共光路3-D角镜消零干涉仪,旨在解决了现有技术中存在的消零干涉谱段窄、需额外的消色差或者相位变换器件,且通常采用非共光路结构导致形成的干涉条纹不够稳定的问题。本发明中待处理的入射光透过第一分束器后被第二分束器分为第一透射光和第一反射光；第一透射光依次经过第一二面直角镜、第一平面反射镜、第二平面反射镜以及第二二面直角镜后再次入射至第二分束器形成第二反射光；第一反射光依次经过第二二面直角镜、第二平面反射镜、第一平面反射镜以及第一二面直角镜后再次入射至第二分束器形成第三透射光；第二反射光与第三透射形成干涉信号；本发明结构稳定、谱段范围宽、消色差、抑制比高且信噪比高。(The invention discloses a wide-spectrum common-path 3-D angle mirror zero-eliminating interferometer, which aims to solve the problems that the zero-eliminating interferometer in the prior art is narrow in spectrum section, needs an additional achromatic or phase conversion device and is not stable enough in interference fringes caused by a non-common-path structure. In the invention, incident light to be processed is divided into first transmitted light and first reflected light by a second beam splitter after penetrating through a first beam splitter; the first transmission light sequentially passes through the first two-surface right-angle mirror, the first plane reflector, the second plane reflector and the second two-surface right-angle mirror and then enters the second beam splitter again to form second reflection light; the first reflected light sequentially passes through the second two-surface right-angle mirror, the second planar reflector, the first planar reflector and the first two-surface right-angle mirror and then enters the second beam splitter again to form third transmitted light; the second reflected light and the third transmission form an interference signal; the invention has stable structure, wide spectrum range, achromatic, high suppression ratio and high signal-to-noise ratio.)

1. A wide-spectrum common-path 3-D angle mirror zero-eliminating interferometer is characterized in that: the beam splitter comprises a first beam splitter (11), a second beam splitter (2), a first two-surface right-angle mirror (3), a second two-surface right-angle mirror (4), a first plane reflecting mirror (5) and a second plane reflecting mirror (6);

after penetrating through the first beam splitter (11), the incident light (1) to be processed is split into first transmitted light and first reflected light by the second beam splitter (2);

the first transmission light sequentially passes through the first two-surface rectangular mirror (3), the first plane reflector (5), the second plane reflector (6) and the second two-surface rectangular mirror (4) and then enters the second beam splitter (2) again to form second reflection light and second transmission light;

the first reflected light sequentially passes through the second two-surface right-angle mirror (4), the second plane reflector (6), the first plane reflector (5) and the first two-surface right-angle mirror (3) and then enters the second beam splitter (2) again to form third reflected light and third transmitted light;

the second reflected light and the third transmitted light are incident to the first beam splitter (11) again to form fourth reflected light;

the intersecting axis of the first two-surface right-angle mirror (3) is vertical to the direction of a first transmission light main optical axis, and forms an angle of 45 degrees with a plane formed by the first transmission light main optical axis and a first reflection light main optical axis;

the intersecting axis of the second two-surface right-angle mirror (4) is vertical to the direction of the main optical axis of the first reflected light and is parallel to the plane formed by the main optical axis of the first transmitted light and the main optical axis of the first reflected light;

the normal of the first plane reflector (5) forms an angle of 67.5 degrees with the main optical axis direction of the incident light (1) to be processed, and the normal is parallel to a plane formed by the main optical axis of the first transmission light and the main optical axis of the first reflection light;

the included angle between the second plane reflector (6) and the main optical axis direction of the incident light (1) to be processed is 112.5 degrees, and the normal is parallel to a plane formed by the main optical axis of the first transmission light and the main optical axis of the first reflection light.

2. The wide-band common-path 3-D gonioscopic nulling interferometer of claim 1, wherein:

defining: the distance from a first reflection point of a first transmission light main optical axis on the first two-surface right-angle mirror (3) to the intersecting axis of the first two-surface right-angle mirror (3) is A; the distance from a first reflection point of the first reflection light main optical axis of the second two-surface right-angle mirror (4) to the intersecting axis of the second two-surface right-angle mirror (4) is B; then A is 2^0.5 times greater than B.

3. The wide-band common-path 3-D gonioscopic nulling interferometer of claim 2, wherein:

the first beam splitter (11) and the second beam splitter (2) both comprise an optical lens and a semi-transparent and semi-reflective light splitting film arranged on the optical lens.

4. The wide-band common-path 3-D gonioscopic null-canceling interferometer of claim 3, wherein:

the semi-transparent semi-reflecting light splitting film is a dielectric film or a metal film.

5. The wide-band common-path 3-D gonioscopic nulling interferometer of any of claims 1, 2, 3, or 4, wherein: further comprising a front optical system (10) arranged at the external light source;

the front optical system (10) comprises a convergent lens, a diaphragm and a collimating lens which are sequentially arranged along a light path.

6. The wide-band common-path 3-D gonioscopic nulling interferometer of claim 5, wherein: also comprises an imaging mirror (7);

and the imaging mirror (7) is arranged on the light path of the fourth reflected light.

7. The wide-band common-path 3-D gonioscopic nulling interferometer of claim 6, wherein: also comprises a detector (8);

and the detector (8) is arranged on the light path of the fourth reflected light and is positioned behind the imaging mirror (7).

8. The wide-band common-path 3-D gonioscopic nulling interferometer of claim 7, wherein: a computer processing system (9) is arranged behind the detector (8).

9. The wide-band common-path 3-D gonioscopic nulling interferometer of claim 8, wherein:

the first two-surface right-angle mirror (3) and the second two-surface right-angle mirror (4) are hollow structures formed by two reflectors.

10. The wide-band common-path 3-D gonioscopic nulling interferometer of claim 8, wherein:

the first two-surface right-angle mirror (3) and the second two-surface right-angle mirror (4) are of solid prism structures.

Technical Field

The invention relates to a null-eliminating interferometer, in particular to a wide-spectrum common-path 3-D angle mirror null-eliminating interferometer.

Background

At present, in the field of astronomical optics, in order to find and research the characteristics of planets outside the solar system, the brightness of only the mother and the sun is searched for 10^-6～10^-10Magnitude planets, zero elimination techniques have been proposed. The basic idea of the zero-eliminating technology for detecting the extremely weak planets under the background of the strong stellar light is to eliminate or effectively suppress the background stellar light through the ingenious optical imaging system design and enhance or effectively retain the planet light.

At present, two main zero elimination technologies exist: one is null-canceling using interferometric techniques, called null-canceling interference, and the other is null-canceling using coronagraphs. The null interference method was first proposed by Bracewell and has the major advantage that all light from the planet (including unpolarized and polarized light) can be received, maximizing the possible detection signal. The anti-zero interference technology uses an interferometer instead of a coronaries component, and eliminates or effectively suppresses background stellar light through a smart interference system design, so that the stellar light is effectively retained. However, the conventional null-canceling interferometer has a narrow spectrum band, needs an additional achromatic or phase-shifting device, and usually adopts a non-common-path structure, so that the formed interference fringes are not stable enough.

Disclosure of Invention

The invention provides a wide-spectrum common-path 3-D angle mirror zero-eliminating interferometer, aiming at solving the problems that the zero-eliminating interferometer in the prior art has narrow spectrum, needs an additional achromatic or phase conversion device and usually adopts a non-common-path structure, so that the formed interference fringes are not stable enough.

In the present invention, 3-D is three-dimensional.

The invention relates to a wide-spectrum common-path 3-D angle mirror zero-eliminating interferometer which is characterized in that:

the device comprises a first beam splitter, a second beam splitter, a first two-surface right-angle mirror, a second two-surface right-angle mirror, a first plane reflector and a second plane reflector;

after penetrating through the first beam splitter, the incident light to be processed is divided into first transmitted light and first reflected light by the second beam splitter;

the first transmission light sequentially passes through the first two-surface right-angle mirror, the first plane reflector, the second plane reflector and the second two-surface right-angle mirror and then enters the second beam splitter again to form second reflection light and second transmission light;

the first reflected light sequentially passes through the second two-surface right-angle mirror, the second planar reflector, the first planar reflector and the first two-surface right-angle mirror and then enters the second beam splitter again to form third reflected light and third transmitted light;

the second reflected light and the third transmitted light are incident to the first beam splitter again to form fourth reflected light;

the intersecting axis of the first two-surface right-angle mirror is vertical to the direction of a first transmission light main optical axis, and forms an angle of 45 degrees with a plane formed by the first transmission light main optical axis and a first reflection light main optical axis;

the intersecting axis of the second two-surface right-angle mirror is vertical to the direction of the main optical axis of the first reflected light and is parallel to a plane formed by the main optical axis of the first transmitted light and the main optical axis of the first reflected light;

the normal of the first plane reflector and the main optical axis direction of incident light to be processed form an angle of 67.5 degrees, and the normal is parallel to a plane formed by the main optical axis of first transmitted light and the main optical axis of first reflected light;

the included angle between the second plane reflector and the main optical axis direction of the incident light to be processed is 112.5 degrees, and the normal line is parallel to a plane formed by the main optical axis of the first transmission light and the main optical axis of the first reflection light.

Further, defining: the distance from a first reflection point of a first transmission light main optical axis on the first two-surface right-angle mirror to the intersecting axis of the first two-surface right-angle mirror is A; the distance between a first reflection point of the first reflection light main optical axis of the second two-surface right-angle mirror and the intersecting axis of the second two-surface right-angle mirror is B; then A is 2^0.5 times greater than B.

Further, the first beam splitter and the second beam splitter each include an optical lens and a semi-transparent and semi-reflective light splitting film disposed on the optical lens.

Further, the semi-transparent semi-reflecting light splitting film is a dielectric film or a metal film.

Further, a front optical system provided at the external light source is also included;

the front optical system comprises a convergent lens, a diaphragm and a collimating lens which are sequentially arranged along a light path.

Further, the device also comprises an imaging mirror;

the imaging mirror is arranged on the light path of the fourth reflected light.

Further, the device also comprises a detector;

the detector is arranged on the light path of the fourth reflected light and behind the imaging mirror.

Further, a computer processing system is arranged behind the detector.

Furthermore, the first two-surface rectangular mirror and the second two-surface rectangular mirror are hollow structures formed by two reflecting mirrors.

Furthermore, the first two-surface rectangular mirror and the second two-surface rectangular mirror are of solid prism structures.

The invention has the beneficial effects that:

1. the structure is stable.

The invention adopts a common light path design, the incident light along a main optical axis or a near axis is divided into a first transmission light and a first reflection light by a second beam splitter, the traveling directions of the two beams are opposite, but the two beams can pass through the same optical device: the first two-face rectangular mirror, the first plane mirror, the second plane mirror and the second two-face rectangular mirror are then converged at the beam splitter again to form interference. The interferometer of the invention can act on the two light beams simultaneously under the thermodynamic change of the external environment, but can cancel each other out, so the formed interference fringe is very stable, and the extraction and the processing of interference signals are easy.

2. The spectral range is wide.

One of the main purposes of the 3-D design of the invention is to generate phase transformation, the bright background will generate destructive interference during imaging, while the dark target in the other field will not cause phase change due to the broadening of the spectral range, and the energy loss of the dark target in the wider spectral range is small. And accordingly, the spectral range is wider than that of the conventional nulling interferometer.

3. And (4) achromatizing.

Because the interferometer adopts a common optical path design and other optical devices except the first beam splitter and the second beam splitter are all reflecting devices, the chromatic aberration of two beams of light generating interference is small, and the two beams of light can be completely achromatic under an ideal condition, so that the rejection ratio of zero interference elimination can be improved.

4. The suppression ratio is high.

Through the design of the common light path of the interferometer system, the phase difference is very small when light with a bright background generates interference, the polarization degree difference is constant, the suppression ratio mainly depends on the light splitting efficiency, the surface type precision, stray light and the like of the second beam splitter of the interferometer, and the suppression ratio to target light can be obtained to the maximum extent.

5. High signal-to-noise ratio.

The invention is suitable for infrared, visible and ultraviolet wave bands, is not limited by optical principles and is mainly limited by spectral response ranges of optical devices and detectors. The interferometer has a wider spectral range, so that a collectable target optical signal is stronger, and the detection with high signal-to-noise ratio and high sensitivity can be realized.

6. And (6) phase conversion.

The invention designs a special 3-D angle mirror zero-eliminating interferometer light path, so that the electric field component of light in the interferometer deflects, and finally the phase reversal of the electric field is formed. So that the phase of the obtained interference fringes is correspondingly deflected without an additional phase modulation device. And causes destructive/constructive interference for light on the main axis and partial destructive/constructive interference for paraxial light, resulting in different treatments of different field of view targets.

7. And (4) cross imaging.

The 3-D angle mirror zero-elimination interferometer light path designed by the invention enables light in the same incident view field to generate two view fields after passing through the interferometer, thereby forming a cross imaging function and being convenient for distinguishing different view field images of a target.

Drawings

FIG. 1 is a schematic structural diagram I of a wide-band common-path 3-D corner mirror null-eliminating interferometer of the present invention;

FIG. 2 is a schematic structural diagram of a wide-band common-path 3-D corner mirror null-eliminating interferometer of the present invention.

In the figure, 1-incident light to be processed, 2-a second beam splitter, 3-a first two-plane square mirror, 4-a second two-plane square mirror, 5-a first plane mirror, 6-a second plane mirror, 7-an imaging mirror, 8-a detector, 9-a computer processing system, 10-a front optical system and 11-a first beam splitter.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The invention discloses a wide-spectrum common-path 3-D angle mirror zero-eliminating interferometer, which is shown by combining a figure 1 and a figure 2 and comprises a second beam splitter 2, a first two-surface right-angle mirror 3, a second two-surface right-angle mirror 4, a first plane reflector 5 and a second plane reflector 6;

the wide-spectrum common-path 3-D angle mirror zero-elimination interferometer is arranged on a light path of incident light 1 to be processed, and a front optical system 10 composed of a lens or a reflecting device can be connected behind an incident light source of the incident light 1 to be processed so as to realize the functions of collimation, stray light elimination and the like of the incident light 1 to be processed.

The incident light 1 to be processed enters the first beam splitter 11 after passing through the front optical system 10, and then enters the second beam splitter 2. The second beam splitter 2 is used for splitting the collimated light transmitted by the first beam splitter 11 into a first transmitted light and a first reflected light, and the first transmitted light and the first reflected light passing through the two arms of the interferometer meet or converge again to generate a second transmitted light, a second reflected light, a third transmitted light and a third reflected light respectively and generate interference. The first beam splitter 11 and the second beam splitter 2 are both optical lenses coated with a semi-transparent and semi-reflective light splitting film, which may be a dielectric film or a metal film, and is related to the spectral range to be detected.

A first two-sided mirror 3 is arranged on the path of the first transmitted light travelling. The intersecting axis of the first two-surface right-angle mirror 3 is perpendicular to the main optical axis direction of the first transmission light (the intersecting axis of the two-surface right-angle mirror is the intersecting line of the two reflection surfaces), and forms an angle of 45 degrees with the plane formed by the main optical axis of the first transmission light and the main optical axis of the first reflection light. Its role is to change the electric field component and the propagation direction of the incident light 1 to be treated and to displace the beam in the height direction (perpendicular to the plane formed by the first transmitted beam and the first reflected beam).

After the first transmitted light beam is reflected by the first two-surface rectangular mirror 3, a first plane mirror is arranged on a traveling light path, and the normal line of the first plane mirror forms an angle of 67.5 degrees with the direction of the main optical axis of the incident light 1 to be processed, which is incident on the second beam splitter 2, and is parallel to a plane formed by the main optical axis of the first transmitted light and the main optical axis of the first reflected light.

After the first transmitted light is reflected by the first plane mirror 5, a second plane mirror 6 is provided on the traveling light path. The normal of the second plane mirror 6 forms an angle of 112.5 degrees with the main optical axis direction of the first incident light, and is parallel to a plane formed by the main optical axis of the first transmitted light and the main optical axis of the first reflected light.

After the first transmitted light is reflected by the second plane reflector 6, the second two-surface right-angle mirror 4 is arranged on a traveling light path, the intersecting axis of the second two-surface right-angle mirror is vertical to the direction of the main optical axis of the first reflected light and is parallel to the plane formed by the main optical axis of the first transmitted light and the main optical axis of the first reflected light, and the light beam is displaced in the height direction (vertical to the plane formed by the first transmitted light and the first reflected light).

The distance from the first reflection point of the main optical axis of the first transmitted light on the first two-surface right-angle mirror 3 to the intersecting axis thereof is A, the distance from the first reflection point of the main optical axis of the first reflected light on the second two-surface right-angle mirror 4 to the intersecting axis thereof is B, and A is 2^0.5 times (0.5 times of 2) of B. At the moment, the interferometer can form a complete common light path, and paths traveled on main optical axes of light beams of two arms of the interferometer are completely overlapped. The distance between the two can not be set according to 2^0.5 times, so that a quasi-common optical path is formed, and the paths traveled by the main optical axes of the two arms of the interferometer are not coincident but are parallel to each other.

The two arms of the interferometer refer to that incident light 1 to be processed is divided into two optical paths of first transmission light and first reflection light after passing through a second beam splitter 2, and the two arms of the interferometer are formed by the optical paths respectively formed by the propagation path of the first transmission light and the propagation path of the first reflection light and the second beam splitter 2. The main optical axis of the incident light (1) to be processed forms an angle of 45 degrees (45-degree incidence) with the normal of the splitting surface of the second beam splitter, and can also be 30 degrees (60-degree incidence). The signal output of the interferometer has two paths, wherein one path is the direction returning to the input light source, and the other path is different from the direction by a certain angle (possibly 60 degrees, 90 degrees, 120 degrees, etc.).

The wavelength range of the incident light 1 to be treated comprises mainly the infrared, visible and ultraviolet parts of the electromagnetic wave.

The first two-surface right-angle mirror 3, the second two-surface right-angle mirror 4, the first plane reflector 5 and the second plane reflector 6 are used for changing the vibration and the propagation direction of light beams, so that interference phases generated in one path of output of the interferometer generate destructive interference on targets on a main optical axis, targets on a non-main optical axis do not completely interfere with each other, the interference phases are changed into a cross imaging mode, and two symmetrical images are generated during imaging.

The first two-sided mirror 3 and the second two-sided mirror 4 can be in the form of a hollow, consisting of 2 mirrors, or in the form of a solid prism.

Meanwhile, in the interferometer, a first two-surface rectangular mirror 3, a second two-surface rectangular mirror 4, a first plane reflector 5 and a second plane reflector 6 are all required to be plated with reflecting films, and the reflecting films can be common metal films and are used for reflecting the whole or partial wave bands from ultraviolet light to visible light and then to infrared light.

The first transmitted light is reflected by the second two-sided right-angle mirror 4 and then returns to the second beam splitter 2, and second transmitted light and second reflected light are generated.

The first reflected light sequentially passes through the second two-surface rectangular mirror 4, the second planar reflector 6, the first planar reflector 5 and the first two-surface rectangular mirror 3 and then returns to the second beam splitter 2, and third reflected light and third transmitted light are generated. The direction in which the first reflected light travels is opposite to the direction of the first transmitted light beam and coincides with each other.

Meanwhile, the second transmitted light meets the third reflected light to generate interference, and the second reflected light meets the third transmitted light to generate interference. The former is a first output interference signal of the interferometer and is emitted along the direction vertical to the incident light 1 to be processed; the latter is a second output interference signal of the interferometer, and is emitted in a direction coinciding with the incident light 1 to be processed, and is emitted again to the first beam splitter 11, and is reflected by the first beam splitter 11 to form fourth reflected light.

The imaging mirror 7 and the detector 8 are sequentially arranged in the traveling direction of the interference signal emitted after being reflected by the first beam splitter 11, and the imaging mirror 7 is used for converging the interference signal to be imaged to the detector 8. The detector 8 is used for collecting interference signals, amplifying, filtering and the like, and providing measurement data for hardware inversion or computer software inversion of related image parameters. The detector 8 may be a CCD or other photoelectric conversion device.

The invention can also be added with a computer processing system 9, the computer processing system 9 carries out data processing and analysis on the interference signal acquired by the detector 8, including preprocessing, error correction, spectral responsivity calibration correction and radiometric calibration correction of interference image bare data, and finally realizes image restoration of a target and high-contrast detection.

The first output interference signal may also be processed through the imaging mirror, detector and computer processing system in the same way as the second output interference signal after passing through the first beam splitter 11.

As shown in fig. 2, the front optical system 10 includes a converging lens a, a diaphragm b and a collimating lens c, which are sequentially arranged, the incident light 1 to be processed is mainly converged by the converging lens a, the diaphragm b filters light to limit the shape of the image plane of the converging lens c and prevent stray light, and the incident light is collimated by the collimating lens c, so that the light passing through the front optical system 10 becomes parallel light. The front optical system 10 may take various forms of refraction, catadioptric and total reflection, etc., with the purpose of converting the target radiation into parallel rays.

The invention relates to a wide-spectrum common-path 3-D angle mirror zero-eliminating interferometer, which comprises the following working processes:

step 1, the incident light 1 to be processed reaches the second beam splitter 2 after passing through the first beam splitter 11, and is split into first transmitted light and first reflected light by the second beam splitter 2.

Step 2, the first transmission light sequentially passes through a first two-surface rectangular mirror 3, a first plane reflector 5, a second plane reflector 6 and a second two-surface rectangular mirror 4, and then returns to the second beam splitter 2 to form second transmission light and second reflection light;

the first reflected light sequentially passes through a second two-surface rectangular mirror 4, a second planar reflector 6, a first planar reflector 5 and a first two-surface rectangular mirror 3, reversely passes through the same optical devices as the first transmitted light beam, and then returns to the second beam splitter 2 to form third transmitted light and third reflected light;

step 3, the second transmitted light and the third reflected light meet to generate interference, a first output interference signal is formed, and the first output interference signal is emitted in the direction vertical to the incident light 1 to be processed; the second reflected light and the third transmitted light meet to generate interference, a second output interference signal is formed, and the second output interference signal is emitted along the direction which is overlapped with the incident light 1 to be processed;

and 4, outputting interference image signals output by two arms of the interferometer as required detection signals. The second output interference signal is reflected by the first beam splitter 11 and then emitted, and then the interference image generated by the second output interference signal is processed by the imaging mirror 7, the detector 8 and the computer processing system 9, so as to obtain the image information of the dark and weak target with the bright central background being zeroed.

The invention can effectively improve the extraction capability of weak targets under high contrast, and has the characteristics of wide spectral range, stable structure, achromatism and cross imaging.

The invention can simultaneously realize phase transformation, wide spectrum, achromatism and more stable structure. The method can be used in the field of astronomy and common optical imaging to obtain the image of a weak and dark target under a bright background, and has a wide application prospect. The optical fiber has the characteristics of ultrahigh contrast detection capability, wide spectral range and a common optical path stable structure in principle.