Non-closed optical path wavefront segmentation interferometer based on planar optical path design

Abstract

The invention relates to a quasi-differential wavefront segmentation double-beam interference device with a planar light path structural design, which has the structural characteristic of a non-closed optical path for transmitting a measurement light beam in a one-way manner. Space coherent light of a transverse mode vector filtering mechanism based on the Huygens principle / phased array principle instead of homologous transmission time coherent light is used as each light source, and a non-closed optical path is realized under the cooperation of a one-way transmission mode on a divided measuring light beam. The problem that the sum of the loop wavelength increment or the frequency increment of a closed path interference device is zero is solved, so that the purpose of measuring the first-level effect of anisotropic physical parameters of a measured object in a linear system is achieved, and the device is particularly suitable for immersion type online measurement. The optical elements have stable performance and sound self-adaptive mechanism and self-diagnosis capability through careful layout of the optical elements; and the method also has wide application prospects in basic physical research and novel navigation / positioning systems. The invention also provides a differential wavefront segmentation and semi-transparent and semi-reflective mirror beam combination interferometer device based on the planar light path structure design, and a wavefront segmentation interferometer device based on the planar light path structure design and provided with a pre-crossing area and a bending type one-way-two-way-common mode combination light path structure. The invention relates to a wavefront segmentation interferometer device of a one-way-two-way combined light path structure which is designed based on a planar light path structure and adopts polarization light splitting-beam combination, optical rotation processing of a reference light beam and original path returning, and a use method of an interference device.

Description

Non-closed optical path wavefront splitting interferometer based on planar optical path design Technical Field

[0001] The present application belongs to the field of photoelectric detection and measuring instruments, and particularly relates to wavefront splitting interferometers, dual-frequency laser interferometers, multi-frequency laser interferometers, white light interferometers, and white laser interferometers. Background Art

[0002] The interference principle of electromagnetic waves can be used to manufacture very high-precision detection instruments, such as laser gyroscopes, wavelength meters, displacement meters, inclinometers, laser interferometer rangefinders, Fourier infrared spectrometers, refractive index meters, etc. However, among the various interferometers that have been made public, due to the many requirements of the interferometer on the light source, most of them use the method of amplitude splitting the same small-section light beam to form a reference beam and a measurement beam respectively to achieve interference measurement. However, this method requires that they have the same action space in the final interference superposition to produce an interference superposition field, which will lead to the inevitable closure of the optical path, and the sum of the loop wavelength increment or frequency increment of any closed path must be 0 (except for the Segnac interference effect, but the Segnac interference effect can only be used for angular displacement / angular velocity). The detection of anisotropy parameters is not suitable for measuring the first-order anisotropy effects of physical objects in spaces such as rectangular coordinate systems or spherical coordinate systems), so they cannot provide the necessary theoretical support for the measurement of the first-order effects of anisotropy parameters; even wavefront splitting interferometers such as Young's double-slit interferometer / Lloyd's mirror are not suitable for measuring the anisotropy parameters of the detection object due to the homology problem of the optical signal, the wavefront structure, and the beam direction. An optional method is to use two freely oscillating and co-frequency light sources to overcome this problem, but such a pair of light sources is difficult to manufacture; and the use of two stabilized lasers with different frequencies will be very difficult because the superimposed signal itself is a time-varying variable, and it is very difficult to grasp the phase change relative to the reference at the same time. To this end, the present application provides a set of universal interferometers (laser and non-laser) that split the wavefronts of large-cross-section plane waves and perform phase matching design to achieve equal optical path lengths to overcome this problem. The principle is based on the Huygens principle, in which the wavefront structure and beam direction are inevitably determined by the phase relationship of the electromagnetic excitation potential at each point (i.e., the phased array principle, in which thin-slice lasers are mainly determined by the high gain ratio of the fundamental transverse mode, while starlight is limited by the constraints of basic geometric principles because the relative distance is much larger than the excitation cross-section, thus overcoming the synchronization problem of the source-end excitation potential. Therefore, the use of a plane wave light source with a large-diameter beam can overcome the problem of the total loop wavelength increment or frequency increment of the closed path being zero. Technical issues

[0003] The technical problem addressed by this application is the measurement of spatial anisotropy parameters of physical objects. This approach, based on the Huygens principle / phased array principle, which relates the phase structure of the electromagnetic wave surface and the direction of beam propagation, uses a transverse mode self-selection mechanism as the fundamental model for wavelet synchronization / spatial filtering to address the difficulty of measuring first-order effects in linear systems using closed optical paths. Technical Solutions

[0004] The invention of this application is as follows: parallel light with a plane wavefront is used as a light source, and after the wavefront of the light beam emitted by the light source is split, beam splitting and steering are performed to form two light beams with different optical paths, while ensuring that at least the measuring light beam is a single unidirectional optical path, and signals are collected through a certain optical path, and a structure with equal equivalent optical paths of each light beam is designed with as few optical elements as possible without generating dispersion as much as possible (the equal optical path is to adapt to natural light / non-laser, and is not a necessary prerequisite for the normal operation of the interferometer. In principle, as long as the range of the interferometer is less than the coherence length of the incident light, that is, the range of the interferometer is less than the maximum interference length, it is not necessary for the equivalent optical paths of each light beam to be strictly equal), and finally the two light beams are converged on the interferometer or the interference result detector assembly (in fact, the collection of vector signals of each light beam before steering or after beam combining still exists, but because of the existence of common mode correlation Therefore, it will not affect the detection results. In addition, when using an array image sensor, a microscope or an image screen as an interference result detector, they can directly replace the original optical path beam combiner without the need for a beam combiner and the related components after it), thereby solving the problem that the wavelength increment or frequency increment integral result of the optical loop is always 0 (the wavelength increment or frequency increment of the optical loop mentioned here is also equivalent to the acceleration of the actual path through which the two light beams pass), providing a theoretical guarantee for the device to measure the anisotropic parameters of the physical object; when the spatial characteristic vector of the measured target is parallel and perpendicular to the direction of the effective measurement beam, respectively, a phase difference value that is proportional to the first-order effect of the measured characteristic quantity can be obtained, thereby solving the problem of effective measurement of the anisotropic parameters of the measured object in the rectangular coordinate system or spherical coordinate system space, and is particularly suitable for immersion physical objects (such as liquid, gas, plasma and other objects). In order to achieve this purpose, this application provides five optional basic implementation structure principles, which are introduced one by one below.

[0005] The first is a quasi-differential wavefront splitting dual-beam interference device based on a planar optical path structure design (see FIG1 ), which is characterized in that: parallel light with a plane wave wavefront is used as a light source (001); an optical path deflector (002, 004) with a turning angle of 90° is provided at the same distance in front of the outgoing light beam of the light source to split the light beam of the light source into an effective measurement beam 1 (013) and an effective measurement beam 2 (014), and the light aperture of the optical path deflector (002, 004) needs to be smaller than half of the light aperture of the light source, and the spacing needs to be set to be smaller than the light source beam diameter minus the effective measurement beam aperture, and is equidistantly distributed from the optical axis (OP) of the light source (i.e., Lm1=Lm2, when a light source with long-term coherence is used, it is only necessary to ensure that the optical path difference minus the range is smaller than the temporal coherence length of the light source), and ensure that the reflected effective measurement beam 1 (01 3) The relationship of being coaxial and facing each other with the effective measurement beam 2 (014); spatial regions of length Lm1 and Lm2 (both must be greater than 1 / 2 of the clear aperture of the effective measurement beam) must be arranged for the effective measurement beam 1 (013) and the effective measurement beam 2 (014) respectively to collect vector signals, and the clear aperture of the spatial region needs to be greater than the clear aperture of the two effective measurement beams. The two spatial regions are respectively called the effective measurement beam 1 working area and the effective measurement beam 2 working area. The two beam working areas are collectively referred to as the effective working area, and the two beams are collectively referred to as the effective beams; in addition, a vertex angle θ with a positive tolerance design (or a positive and negative tolerance design less than the diffraction angle, when the vertex angle tolerance is greater than the beam diffraction angle, the tolerance range must be adjusted in the positive direction, or the design value must be changed to >90° to prevent the two beams from not intersecting) is set on the optical axis (OP) of the light source. T=90° blade prism reflector is used as a beam-combining mirror (003), the center height of which is equal to or higher than 1 / 2 of the aperture of the optical path deflector (002, 004), wherein the reflecting surface is the outer surface of the two right-angled sides, and the bisector of the vertex angle is adjusted to coincide with the axis of the light source, and the light field is superimposed on the diffraction angle or positive tolerance angle of the light beam reflected by the two right-angled surfaces of the beam-combining mirror. When the positive deviation of the vertex angle is greater than the diffraction angle of the light beam, it is also necessary to ensure that the installation position of the interference result detector component (007) is within the far intersection point of the two light beams (the farthest point where the two light beams intersect). In order to improve the detection efficiency of the equipment, the aforementioned optical path deflectors (002, 004) can also be replaced with a single rotationally symmetrical structure with a 90° top angle hollow inner surface conical reflector (a hollow conical reflector with a conical or angular cone structure, a hollow conical retroreflector, or collectively referred to as an inner reflection concave conical reflector. In order to optimize the layout, the top cone portion can be cut off so that the light beam can pass through the hole in the middle) or a rotationally symmetrical prism, and the deflection beam combiner (003) is also replaced with a corresponding outer surface reflection conical reflector (or simply referred to as an outer reflection convex conical reflector). The reflecting surfaces of the two groups of reflectors are set to the same height, or are set to a position where the effective aperture of the beam combining deflection mirror (003) contains at least 1% of the cross section of each incident light beam. The two light beams that are deflected by the deflection beam combiner (003) are also provided with an interference result detector assembly (007) (with the detection surface perpendicular to the axis of the light source) in the interference area in front of the two light beams that travel ahead. The interference result is collected and measured to obtain the phase difference of the two effective measurement light beams. In this embodiment, the portion of the wavefront light beam before passing through the two optical path deflectors is respectively called measurement beam 1 (011) and measurement beam 2 (012), and the spatial area through which these two portions of the light beam pass is called the first measurement beam channel and the second measurement beam channel.

[0006] The second type is an interferometer device based on a planar optical path structure design with differential wavefront splitting and semi-transparent and semi-reflective mirror beam combining (see Figure 2), which is characterized in that: on the basis of the first implementation method, the knife-edge prism finite field beam combining method is replaced with a semi-transparent and semi-reflective mirror (105) to achieve coaxial beam combining, so as to achieve infinite interference / flat field interference. In order to meet the coaxial beam combining, it is necessary to set two optical path deflectors with different distances relative to the light source, and add a 90° optical path deflector (103) to meet the beam combining incident angle requirement of the semi-reflective and semi-reflective mirror. In addition, because the semi-reflective and semi-reflective mirror beam combining has two groups of interference output light, a set of auxiliary detector components (107) is added to measure the beam direction and spectral composition of the two coherent light beams, which serves as a reference signal for automatic calibration, correction of assembly errors and parameter drift, and can also be used to monitor the beam quality and wavefront distortion and evaluate the effectiveness of the detection results.In order to facilitate the distinction from the first implementation, the present implementation changes the component numbering and still uses parallel light with a plane wave as the light source (101); at different distances (generally required to be greater than the effective measurement beam aperture) in front of the light beam emitted by the light source, optical path deflectors (102, 104) with a turning angle of 90° are provided to split the light beam of the light source into an effective measurement beam 1 (113) and an effective measurement beam 2 (114), and the aperture of the optical path deflectors (102, 104) needs to be smaller than half of the light source aperture, and the spacing needs to be set to be smaller than the light source beam diameter minus the effective measurement beam aperture. The effective measuring beam 1 (113) and the effective measuring beam 2 (114) must be parallel and facing each other. The effective measuring beam 1 (113) and the effective measuring beam 2 (114) must be arranged with spatial lengths of Lm1 and Lm2 (both must be greater than 1 / 2 of the aperture of the effective measuring beam) for collecting vector signals. The aperture of the spatial area must be greater than the aperture of the two effective measuring beams. The regions are respectively referred to as the effective measurement beam 1 working area and the effective measurement beam 2 working area; an optical path deflector (103) with a turning angle of 90° is provided at the same relative distance from the light source as the optical path deflector (102) and at the position of the axis of the light source (i.e., between the initial state measurement beam 1 (111) and the measurement beam 2 (112)), for making the effective measurement beam 1 (113) turn 90° again so that the extended section (115) of the measurement beam 1 after the turn can maintain an orthogonal relationship with the effective measurement beam 2 (114), so that they can converge at the interference beam combiner; at a distance from the light source equal to the distance from the optical path deflector (10 4) is also provided on the axis of the light source at a distance of from 0.5 to 1.5°, and a semi-transparent semi-reflective beam combining mirror (105) for interference beam combining is provided; one group of interference superposition light (116) after beam combining is sent to an interference result detector assembly (106) provided in front of the light beam for measurement to obtain the phase difference between the two effective measurement beams; the other group of interference superposition light (117) is sent to an auxiliary detector assembly (107) provided in front of the light beam for measuring the beam direction and spectral composition of the two coherent light beams, which are used as reference signals for automatic calibration, correction of assembly errors and parameter drift, and can also be used to monitor the beam quality and wavefront distortion and evaluate the effectiveness of the detection results.

[0007] The third type is a wavefront splitting interferometer device (see FIG3 ) designed based on a planar optical path structure, having a pre-crossing region and a bent single-pass-double-pass-common mode combined optical path structure, which is characterized by: using parallel light with a plane wave as a light source (201); and providing optical path deflectors (202, 204) with a turning angle of 90° at different distances (generally required to be greater than the effective measurement beam aperture) in front of the light beam emitted by the light source, so as to split the light beam of the light source into an effective measurement beam (214) and a common mode beam (215). The common-mode reference beam (213) is a common-mode reference beam, and the aperture of the optical path deflector (202, 204) needs to be less than half of the aperture of the light source, and the spacing needs to be set to be less than the diameter of the light source beam minus the aperture of the effective measurement beam, and it is ensured that the reflected effective measurement beam (214) and the common-mode reference beam (213) are parallel and in the same direction; a spatial region with a spatial length greater than 1 / 2 of the aperture of the effective measurement beam must be arranged for the effective measurement beam (214) to collect vector signals, and the aperture of the spatial region needs to be The spatial area is larger than the aperture of the effective measurement beam, and is called the effective measurement beam working area; a sample carrier (208) is provided at the intersection of the beam (211) in this area and the effective measurement beam (214) before passing through the optical path deflector (202); an optical path deflector (203) with a deflection angle of 90° is provided in the direction of the common mode reference beam (213), so that the reference beam (215) after the deflection can maintain an orthogonal relationship with the effective measurement beam (214); at the same time, a measurement optical path deflector (203) with a deflection angle of 90° is provided in the direction of the common mode reference beam (213), so that the reference beam (215) after the deflection can maintain an orthogonal relationship with the effective measurement beam (214); The vertical distance Lzr between the deflector (204) and the deflector (202, 203) of the reference light path is half of the effective measurement beam length Lzm, realizing equal optical path design; a semi-transparent semi-reflective beam combiner (205) is provided at the intersection of the effective reference beam 2 (215) and the effective measurement beam (214); one group (216) of the combined interference beams is directed to an interference result detector assembly (206) provided in front of the beams for measurement, thereby obtaining the phase difference between the effective measurement beam and the effective reference beam. Another group of secondary interference beam sets (217) is directed to an auxiliary detector assembly (207) provided in front of the beams for measuring the beam directions and spectral components of the two coherent beams, which serve as reference signals for automatic calibration, correction of assembly errors and parameter drift, and can also be used to monitor beam quality and wavefront distortion, and evaluate the effectiveness of the detection results.

[0008] The fourth type is a wavefront splitting interferometer device based on a planar optical path structure design, which adopts a single-pass and double-pass combined optical path structure with polarization splitting / combining and optical rotation processing of a reference beam and returns along the original path. The device is characterized in that: a linearly polarized parallel light with a plane wave wavefront is used as a light source (301); an optical path deflector (304) with a deflection angle of 90° is provided in front of the light beam emitted by the light source; a thin-film (<10λ) polarization beam splitter (305) is installed on another part of the light path of the parallel light beam emitted by the light source and at a position with the same vertical distance from the light source as the optical path deflector (304), and the position is adjusted so that the vibration vector of the light beam emitted by the light source is consistent with the polarization direction required to pass through the PBS; and a polarization deflector (305) is installed in the path where the reference beam continues to travel. A thin (<10λ) 1 / 4λ glass slide (307) is provided, and the polarization vector of the glass slide (either the fast axis or the slow axis is not limited) is adjusted to be 45 degrees with the polarization vector of the incident light beam; a front surface reflector (308) with a planar structure is installed after the effective reference beam passes through the 1 / 4λ glass slide, and the mirror surface of the reflector is set to be parallel to the wavefront of the effective reference beam, and the equivalent optical path length of the spatial length Lmr+Ls / 2 passed by the effective reference beam is set to be half of the effective measurement optical path length Lmx+Ls / 2, that is, k(2Lmr+Ls / 2)=pLmx, wherein k and p are the equivalent optical path coefficients of the effective reference beam and the effective measurement beam, respectively, and when the refractive index of the Ls interval is consistent with that of Lmr, it can be simplified to 2Lmr+Ls / 2 =Lmx; an interference result detector assembly (306) is installed on the path of the combined interference light beam (316) to measure the phase difference between the effective measurement light beam and the effective reference light beam; in order to ensure the lowest possible dispersion and scattering, the polarization splitting beam combining mirror here should be a thin-film polarization beam splitter (such as a metal wire grid polarizer) or a polarization beam splitter cube made of an ultra-low dispersion substrate, and an anti-reflection film should be coated on the light-transmitting surface as much as possible.

[0009] The fifth type is a wavefront splitting interferometer device (see Figure 4) based on a planar optical path structure design, which adopts polarization splitting and combining, optical rotation processing of the reference beam, and returns along the original path, and is composed of a single-pass and double-pass combined optical path structure with dispersion compensation. Its characteristics are: on the basis of the fourth solution, the thin-plate polarization beam splitter is replaced by a polarization beam splitter with a glass or crystal substrate (such as a wire grid polarization beam splitter cube), and the thin-plate 1 / 4λ glass is replaced by a common 1 / 4λ glass with an optical substrate. In addition, a pair of 1 / 2λ glass plates (302, 303) with the same thickness and material as the 1 / 4λ glass plate in the reference beam and a PBS beam splitter (309) with completely the same parameters as the beam combiner (305) are added to the effective beam channel as dispersion compensation components. The two 1 / 2λ glass plates are respectively placed in front of and behind the optical path of the PBS beam splitter (309), and the polarization vector of the glass plate is adjusted. The vibration vector of the incident light beam maintains a 45° relationship, the transmission polarization vector of the PBS spectrometer (309) should be consistent with the polarization vector of the incident light beam (when the light source has a single polarization direction, the PBS spectrometer should be rotated 90° around the optical axis with another PBS so that the polarized light beam passing through the half-wave plate can completely pass through the PBS), and the position of the reference beam reflector (308) with unequal optical path is adjusted so that the time when the same wavefront emitted by the light source reaches the beam combiner or the interference result detector surface in the initial state is consistent, that is, to ensure that 2kLmr=Lmx in Figure 5 of the specification, where k depends on the ratio of the change in the equivalent optical path of the entire effective reference beam caused by the material and thickness of the 1 / 4λ glass. Since the two beams are not strictly isotropically co-mode, in practical applications, equal optical path can also be ensured by online fine-tuning the position of the optical adjustment frame.

[0010] In the above five schemes, in order to ensure the lowest possible parameter drift, dispersion, and scattering, all fully reflective mirrors should use flat front surface reflectors with a reflective film structure without a protective film made on a substrate with a low thermal expansion coefficient. The semi-transparent and semi-reflective beam combiners should use thin-film (<10λ) elements realized by multi-layer hard dielectric film re-plating with an axially symmetrical structure, or semi-transparent and semi-reflective beam combiners with a semi-reflective film sandwiched between optical substrates of the same material and the same thickness.

[0011] In the five aforementioned solutions, the interference result detector can be any device capable of measuring interference results, such as an image screen, frosted glass, a photodetector, or an image sensor. Preferably, a photodetector or an array image sensor is used to convert the superimposed field intensity signal of the reference and measurement beams into an electrical signal, which is then processed and sampled by conventional circuits and then sent to an electronic computer for computational analysis. When the interference result detector is an array image sensor, the image sensor's light-receiving surface can be adjusted to a non-strictly parallel position with the combined interference wavefront, or the effective reference beam's wavefront can be adjusted to a non-strictly perpendicular position with the effective measurement beam's wavefront (the relative position of the two beams before combining), thereby achieving an interference result of magnitude 0 or higher.

[0012] In the above five schemes, the parallel light source with a plane wave wavefront can be a fixed light source integrated in the system, or a light source dispersed outside the measurement system, such as sunlight or starlight. Replacing the parallel light source in this application with sunlight or starlight can achieve higher-precision measurement (because the measurement accuracy is proportional to the length of the effective measurement beam, and it is difficult for the light source integrated in the system to achieve a large beam diameter while ensuring small wavefront distortion); the spectral composition of the light source can be single-frequency laser, monochromatic light, white light, white laser, dual-frequency or multi-frequency laser, or dual-color or multi-color spontaneous radiation. In order to ensure the stability and accuracy of the measurement results, polychromatic light is preferably used as the light source. By detecting the displacement of the zero-order interference on the interference result detector, or jointly solving the phase shift value of the combined frequency by the fractional part of the phase shift of each frequency point, a more stable and accurate result and a larger measurement range can be obtained (see Tilford CR. Analytical procedure for determing lengths from frac2 tional fringes[J]. Applied Optics, 1987, 16(7)); when a polychromatic light source is used, a wavelength division multiplexer can be placed in front of the interference result detector to avoid the problem of multi-frequency superposition response.

[0013] In the above five schemes, the optical path deflector and the semi-transparent and semi-reflective mirror can be installed on a motion mechanism that can move back and forth along the axis of the incident and outgoing light beams, and the entire device can be installed on a two-dimensional turntable such as a theodolite, so that the device has the functions of measuring the spatial wavelength of the optical signal, measuring the spatial position of the equipment, self-calibration, self-correction, detecting the current phase, performing automatic measurement and target tracking.

[0014] In the above-mentioned schemes 2 and 3, a set of auxiliary detectors (107, 207) can be installed on the traveling wave optical path of the secondary interference beam set (117, 217) after the coherent beam combination by the semi-transparent and semi-reflective mirrors to monitor the parameters such as the beam direction, beam quality, wavefront distortion, and spectral composition of the reference beam and the measurement beam, which serve as reference signals for automatic calibration, correction of assembly errors and parameter drift; the beam direction can be achieved by focusing and imaging the reference beam and the measurement beam, and using a planar array image sensor, a four-quadrant detector, etc. to detect the beam inclination, which can be used for self-calibration, sunlight or starlight tracking, etc.; in addition, other optical measurement components can be further expanded, such as optical frequency measurement, spectrum measurement, wavelength measurement, etc., for the purposes of automatic correction, equipment calibration, measurement value compensation, etc.; for the interferometer structure with two-way interference light output, the placement positions of the auxiliary detector and the interference result detector component are interchangeable. When there are no special requirements, it is preferred to install the interference result detector on the path where each beam has an equal number of reflections.

[0015] The typical usage of a non-closed optical path wavefront splitting interferometer based on a planar optical path design involves pre-setting the device in a posture independent of the measured object (generally, keeping the measured vector parallel to the effective measurement beam wavefront or perpendicular to the axis of the effective measurement beam) and reading the initial phase difference. Then, by filling or installing an anisotropic medium with the measured light on the sample stage (if available), or in the effective reference and measurement workspaces, or adjusting the device posture to keep the measured vector parallel to the axis of the effective measurement beam (or perpendicular to the wavefront of the effective measurement beam), the measured phase difference is read. If the measured object exhibits anisotropy, the phase difference obtained will differ from the initial phase difference. The anisotropic parameters of the object being measured are determined by subtracting the measured phase difference from the initial phase difference. When used for motion and fluid detection, the interferometer posture should be adjusted to keep the effective measurement beam parallel to the motion / flow vector.

[0016] Definition of Terms: In implementations 3 through 5, the spatial region through which the reference beam and the measurement beam pass perpendicularly between their intersection and their interferometric combination is called the effective reference beam operating area, and this section of the beam is called the effective reference beam. The spatial region through which the measurement beam passes between its intersection with the optical path deflector and its intersection with the reference beam is called the effective measurement beam operating area, and this section of the beam is called the effective measurement beam. These two beam operating areas are collectively referred to as the effective operating area, and these two sections of the beam are collectively referred to as the effective beam. The entire device referred to in this application refers to the base and all components mounted thereon, but does not include the two-dimensional theodolite turntable. This is for the convenience of describing the reference upon which the interferometer's attitude depends. That is, in this application, the reference of the interferometer device is the fixed portion of the theodolite, but the theodolite remains a key component of the device. Furthermore, all mathematical or geometric terms used in this application (such as plane wave, orthogonal, perpendicular, parallel, simultaneous, equal, etc.) are measured based on practical engineering standards and do not represent ideal mathematical or geometric relationships without deviation. Generally, they are sufficient to be at least twice the resolution of the specific device or component. In this application, there is no special restriction on the initial state, because different test objects require different initial states to obtain the most appropriate results. However, some measurements require a limited initial state, such as motion and fluid measurements. The initial state should be static, or the plane formed by the effective measurement beam is orthogonal to the measured vector. This is the optimal initial state. Beneficial effects

[0017] The solution provided in this application offers more stable performance and a more robust adaptive mechanism for measuring spatial anisotropy parameters of physical objects, with lower implementation costs. Besides being useful for materials research, it is also expected to play a role in navigation, direction finding, and / or positioning without a cooperating target, as well as in fundamental physics research. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a schematic diagram showing the principle of implementing a quasi-differential wavefront splitting dual-beam interferometer device;

[0019] FIG2 is a schematic diagram showing the principle of an interferometer device for differential wavefront splitting and beam combining using a semi-transparent and semi-reflective mirror;

[0020] FIG3 is a schematic diagram showing the implementation principle of a wavefront splitting interferometer having a pre-crossed region and a bent single-pass-double-pass-common-mode combined optical path structure;

[0021] FIG4 is a schematic diagram showing the implementation principle of a wavefront splitting interferometer using a single-pass / double-pass combined optical path structure with polarization splitting / combining and optical rotation processing of a reference beam and returning the reference beam along the original path;

[0022] FIG5 is a schematic diagram showing the principle of implementing a wavefront splitting interferometer that uses a single-pass / double-pass combined optical path structure with dispersion compensation and polarization splitting / combining, optical rotation processing of the reference beam and returns it along the original path.

[0023] In FIG1 : 001 ) parallel light source, 002 ) measuring beam 1 reflecting mirror, 003 ) beam combining and turning mirror, 004 ) measuring beam 2 reflecting mirror, 007 ) interference result detector assembly, 011 ) measuring beam 1, 012 ) measuring beam 2, 013 ) effective measuring beam 1, 014 ) effective measuring beam 2, 017 ) effective interference beam 1, 018 ) effective interference beam 2.

[0024] In FIG2 : 101) parallel light source, 102) primary reflector of measurement beam 1, 103) secondary reflector of measurement beam 1, 104) reflector of measurement beam 2, 105) semi-transparent and semi-reflective interference beam combiner, 106) interference result detector assembly, 107) auxiliary detector assembly, 111) measurement beam 1, 112) measurement beam 2, 113) effective measurement beam 1, 114) effective measurement beam 2, 115) extended section of measurement beam 1, 116) primary interference beam set, 117) secondary interference beam set.

[0025] In FIG3 : 201) parallel light source, 202) reference beam reflector 1, 203) reference beam reflector 2, 204) measurement beam reflector, 205) semi-transparent and semi-reflective interference beam combiner, 206) interference result detector assembly, 207) auxiliary detector assembly, 208) sample stage, 211) reference beam, 212) measurement beam, 213) common mode reference beam, 214) effective measurement beam, 215) effective reference beam 2, 216) primary interference beam set, 217) secondary interference beam set.

[0026] In FIG4 : 301 ) polarized parallel light source, 304 ) measurement beam reflector, 305 ) PBS beam splitter / combiner, 306 ) interference result detector assembly, 307 ) 1 / 4λ glass slide, 308 ) reference beam reflector, 311 ) reference beam, 312 ) measurement beam, 315 ) effective measurement beam, 316 ) interference beam set, 317 ) effective reference beam 1, 318 ) effective reference beam 2.

[0027] In FIG5 : 301) polarized parallel light source, 302) front 1 / 2λ glass slide, 303) rear 1 / 2λ glass slide, 304) measurement beam reflector, 305) PBS beam splitter / combiner, 306) interference result detector assembly, 307) 1 / 4λ glass slide, 308) reference beam reflector, 309) PBS beam splitter, 311) reference beam, 312) measurement beam 1, 313) measurement beam 2, 314) measurement beam 4, 315) effective measurement beam, 316) interference beam set, 317) effective reference beam 1, 318) effective reference beam 2, 319) measurement beam 3. Best Mode for Carrying Out the Invention

[0028] The detailed implementation steps of the quasi-differential wavefront splitting dual-beam interferometer include:

[0029] Component selection: A multi-line thin-disk laser with a 120mm×25mm rectangular spot was selected as the parallel light source (001); a silver-coated front surface reflector with a 45° installation and a clear aperture of about 22mm was selected as the optical path deflector (002, 004), and an optical adjustment frame with a 45-degree bevel installation was selected as the installation base for each; a knife-edge prism reflector designed and manufactured with positive tolerance and a right-angle outer surface reflection was selected as the beam combining deflection mirror (003) , and select an optical adjustment frame that does not block its three light-transmitting surfaces as the installation basis. The two types of turning reflectors mentioned above can also be directly replaced by an internal reflection concave cone mirror and an external reflection convex cone mirror and a matching optical adjustment frame; select a surface array camera group with a built-in wavelength division multiplexer as the interference result detector component (007); In addition, a customized base that conforms to the layout of the schematic diagram is required as the basis for the installation of various components and assemblies, and a set of two-dimensional longitude and latitude turntables that can be installed on the base and can rotate 360 ​​degrees continuously without dead angles on each axis to adjust the posture of the base (the entire set of measurement components);

[0030] Parameter requirements: The light-passing surface dimensions of the above optical components need to match; unless otherwise specified, the optical axis center design and manufacturing position tolerance of all components (including the base) is ±0.1mm, and the angle tolerance is ±2'; the front surface of the optical path deflector (002, 004) is 45 degrees ±2' to the wavefront emitted by the light source, or the θ012 and θ014 marked in Figure 1 must meet 45°±2' (when a light screen or array image sensor is used, the tolerance range is ±1°, the same below); the vertex angle size of the deflection beam combiner (003) is a positive tolerance knife-edge prism reflector of 90°+0.5°, and it must be maintained Verify that θ015 and θ016 are equal, so that the angles θ017 and θ018 between the two reflected light beams and the axis of the light source are as equal as possible, and the intersection angle θ017 + θ018 between the two beams is ≤ 1°. The optical path lengths of the two effective measurement beams must be consistent, with a tolerance of at least < ±λ / 16 (λ is the operating wavelength of the light source, a requirement applicable only when the light source's linewidth is greater than 100 MHz). In this embodiment, Lm1 = Lm2 = 47 mm, and the repeatability of the phase is no less than λ / 16. To improve measurement accuracy, it is necessary to increase Lm1 and Lm2 and provide a parallel light source with a larger spot length.

[0031] Installation process: After all the aforementioned components and assemblies are installed in place according to the design principle diagram, first adjust all the beams related to the measurement to the same plane height and lock all free quantities except plane rotation; then adjust the angle tolerance of θ012 and θ014 to within 45°±2'; then adjust the angles of θ017 and θ018 to be equal; then put the entire device into a dark room or a light-proof cavity; connect the output of the array camera (007) to the computer and monitor the real-time image in real time; adjust the plane constructed by the beam of the interferometer device to a posture that is independent of the measured vector (generally vertical) by rotating the theodolite. After the interference image of the array camera (007) is stable, fine-tune the left and right position of the knife-edge prism reflector (003) on the axis of the effective measurement beam so that the 0-order interference of each spectral line coincides (this requirement is only required when the spectral line width of the light source is greater than 100MHZ)). This is the initial phase of the device;

[0032] Finally, the sample (if any) is placed in the effective working area, or the device is adjusted so that the measured field isointensity plane is parallel to the wavefront of the effective measurement beam, or the measured motion / flow vector is parallel to the effective measurement beam. The phase indications of the current spectral lines are then re-recorded, and the sum frequency phase value is solved using a system of simultaneous equations. The phase change is then calculated by subtracting the initial phase from this value. The phase change is then mapped to the measured physical quantity using a mathematical formula related to the measured quantity, thereby achieving the purpose of measuring the anisotropic characteristic parameters of the target. Preferably, these mathematical formulas related to the physical relationship should be compiled into an application program to facilitate automated calculations and output various related reports. Modes for Carrying Out the Invention

[0033] Example 2 (see FIG2 ): The detailed implementation steps of the interferometer with differential wavefront splitting and half-transparent and half-reflective mirror beam combining include:

[0034] Component selection: a 120mm beam diameter thin-disk laser and a multi-spectral laser generated by nonlinear frequency doubling are selected as the parallel light source (101); a silver-coated front surface reflector mounted at 45° is selected as the optical path deflector (102-104), and an optical adjustment frame mounted at 45° is selected as the installation base for each; a semi-transparent and semi-reflective mirror with an anti-reflection film on the outer surface, the same material and equal thickness on both sides, and an optical substrate sandwiching a semi-reflective film is selected as the interference beam combiner (105). , and select an optical adjustment frame that does not block the four light-passing surfaces as the installation base; select a multi-channel photodetector with a wavelength division multiplexer as the interference result detector component (106); select a spectrometer / wavelength meter and camera component with an internal light splitting device and an imaging lens as the auxiliary detector group (107), which is used for beam inclination measurement and spectrum measurement; in addition, a custom-made base that conforms to the schematic layout is required as the basis for the installation of various components and assemblies, and a set of two-dimensional longitude and latitude turntables that can be installed on the base and can rotate 360 ​​degrees continuously without dead angles on each axis to adjust the posture of the base (the entire set of measurement components);

[0035] Parameter requirements: the light-transmitting surface sizes of the above optical components need to match each other, and standard sizes such as 12.7mm, 20mm, and 25mm should be selected as much as possible to facilitate finding a matching mounting bracket. The beam diameter of the disk laser is generally required to be greater than 3 times the designed light-transmitting aperture of the effective beam; unless otherwise specified, the design and manufacturing position tolerance of the optical axis center of all components (including the base) is ±0.1mm, and the angle tolerance is ±2'; the front surface of the optical path deflector (102, 104) is 45 degrees ±2' relative to the wavefront emitted by the light source, or θ112 and θ114 marked in Figure 2 must meet 45°±2' (when a light screen or array image sensor is used, the tolerance range is ±1°, the same below); the front surface of the optical path deflector (103) is 45 degrees ±2' relative to the wavefront of the effective measurement beam 1 (113), or θ113 marked in Figure 2 must meet 45°±2'; The angles between the reflective film surface of the coherent beam combiner (105) and the axis lines of the two effective measurement beams are both 45 degrees ± 2', that is, θ115 and θ116 marked in FIG2 need to satisfy 45 degrees ± 2'; the optical path lengths of the two effective measurement beams need to be consistent, and the tolerance needs to be at least < ± λ / 16 (λ is the operating wavelength of the light source, and this requirement does not apply when a laser is used as the light source). In this embodiment, Lm1 = Lm2 = 38.5 mm, and the repeat phase accuracy is not less than λ / 16. If the measurement accuracy needs to be improved, Lm1 and Lm2 need to be increased and a parallel light source with a larger beam diameter needs to be provided at the same time;

[0036] During the assembly and adjustment process, after all the aforementioned components and assemblies are installed in place according to the design principle diagram, it is first necessary to adjust all the beams related to the measurement to the same plane height and lock all free quantities except for plane rotation; then adjust the angles and tolerances of θ112 and θ114 within 45°±2'; then adjust the angles and tolerances of θ113 within 45°±2'; then adjust the angles and tolerances of θ115 and θ116 within 45°±2'; then place the entire device in a dark room or a light-proof cavity; connect the various outputs of the interference result detector component (106) to the multi-channel phase meter; connect the auxiliary detector component (107) to the acquisition card and monitor the angle of the incident light beam, and start the parallel light source to adjust the aforementioned angle online to make the angle deviation range as small as possible, and monitor whether the spectral line width of the light source exceeds the standard; by rotating the theodolite, adjust the plane constructed by the effective light beam of the interference device to the plane being measured. The position of the measurement vector is independent (generally vertical). After the phase indication of each photoelectric detector of the interference result detector component (106) is stable, the front and rear positions of the optical path deflector (103) on the axis of the effective measurement beam 1 (113) are fine-tuned to achieve a state where the interference phases of the photoelectric detectors of each spectrum line are all equal (this requirement is not required when laser is used as the light source). This is the initial 0 phase of the device (generally speaking, when the two split beams of light emitted by the light source have the same number of reflections after being combined, the 0-level interference state is the relative maximum output of the photoelectric sensor. If it is not the same, it depends on the odd or even value of the difference in the number of reflections of the two beams of light. When the difference is an odd number, the photoelectric sensor outputs the minimum value, and when the difference is an even number, the photoelectric sensor outputs the maximum value). The more accurate initial phase values ​​are recorded respectively, and the phase values ​​of each spectrum line are combined to obtain the phase value of the sum frequency / frequency division (if the signal requires a larger range);

[0037] Finally, the sample is loaded into the effective working area (if any), or the device is adjusted so that the measured field is parallel to the effective measurement beam wavefront, or the measured motion / flow vector is parallel to the effective measurement beam. The phase indications or frequency shift values ​​of each photodetector are then re-recorded. The phase value of the sum / fraction frequency is first solved using a system of simultaneous equations. Based on the mathematical formulas physically associated with the measured quantity, the mapping of the phase change or frequency change to the measured physical quantity is then analyzed, thereby achieving the purpose of measuring the anisotropic characteristic parameters of the target. Preferably, these physically associated mathematical formulas should be compiled into an application program to facilitate automated calculations and output of various related reports.

[0038] Example 3 (see FIG3 ): The detailed implementation steps of a wavefront splitting interferometer having a pre-crossing region and a bent single-pass-double-pass-common-mode combined optical path structure include:

[0039] The selection of parts is the same as that of Example 2 (the types of parts are the same as those of Example 2, and the part numbers are shown in FIG3 ); in addition, this embodiment can also select a sample carrier (208) to place the object to be measured. The specific selection depends on whether the sample is liquid, gas, or solid and the pressure to determine whether a container or a fixture is required; the two reference beam reflectors (202, 203) can be installed on the same translation table that moves up and down along the axis of the effective reference beam 2 (215), so as to realize linkage to simplify the steps of equal optical path fine-tuning; in addition, the turning mirrors (202, 204) can be installed on the sliding table that moves back and forth along the axis of the outgoing beam to verify the wavefront structure of the light source and measure the spatial wavelength and verify the change in the spatial wavelength; in addition, a custom-made base that conforms to the layout of this schematic diagram ( FIG3 ) is required as the basis for the installation of various parts and components;

[0040] Parameter requirements: the common mode section (213) of the reference beam and the effective measurement beam (214) need to be strictly parallel, and the angle between the two beams must not be greater than 5", and the distance Lzr between the two beams also needs to be strictly equal to half of the detection area length Lzm of the effective measurement beam (214) (tolerance λ / 16), that is, 2Lzr=Lzm±(λ / 16). Note that if the light transmission refractive index of the semi-transparent semi-reflective beam combiner (205) is not equal to the other parts through which the beam passes, Lzr and Lzm need to be converted into the equivalent optical path length of the other parts to maintain the relationship; other parameter requirements are the same as those in Example 2;

[0041] The assembly and adjustment process is the same as that of the second embodiment (see FIG. 3 and the relevant parts of the accompanying drawings for component numbers and parameter markings, and see the second solution in the invention content section for the working principle).

[0042] Example 4 (see FIG4 ): The detailed implementation steps of a wavefront splitting interferometer using a single-pass / double-pass combined optical path structure with polarization splitting / combining and optical rotation processing of a reference beam and returning the reference beam along the original path include:

[0043] Component selection: a 120 mm diameter linearly polarized output thin-film laser and a multi-spectral linearly polarized laser generated by nonlinear frequency doubling are selected as the parallel light source (301); a thin-film polarization beam splitter with a thickness of about 5 μm is selected as the beam splitter / beam combiner (305), and a mounting bracket with four-sided light transmission is selected as the mounting base; a thin-film 1 / 4λ glass plate with a thickness of less than 5 μm (307) is selected, and a hollow structure glass plate mounting adjustment bracket assembly that can rotate along the optical axis is selected as the mounting base; a 0-degree mounted silver-coated front surface reflector is selected as the reference beam reflector (308), and a 0-degree mounted optical adjustment bracket is selected as the mounting base; the selection of the interference result detector assembly and the optical path deflector (304) is referred to in Example 2 (see FIG4 for the component number); in addition, a custom-made base that conforms to the schematic layout (FIG4) is required as the mounting base for various components and assemblies;

[0044] Parameter requirements: the light plane of the beam splitter / combiner (305) needs to maintain a parallel relationship with the wavefront of the incident effective reference beam, with a maximum allowable tolerance of ±2′, and the polarization vector of the beam splitter / combiner (305) needs to maintain a 45°±2′ relationship with the polarization vector of the incident beam; the light plane of the reference beam reflector (308) needs to maintain a parallel relationship with the wavefront of the incident effective reference beam, with a maximum allowable tolerance of ±2′; other parameter requirements are the same as those of Example 2;

[0045] During the adjustment process, after all components are installed in place, the vibration vector of the light source's output beam is first adjusted to be consistent with the polarization direction required to pass through the PBS (generally speaking, the light source's vibration vector is parallel to the design plane and has a 45° / 135° inclination angle with the PBS); the polarization vector of the 1 / 4λ glass (307) (either the fast axis or the slow axis) is adjusted to be 45° (based on the rotation angle of the optical axis) with the polarization vector of the incident effective reference beam; and then the adjustment is performed according to the adjustment steps and methods of Example 2 (no auxiliary detector installation is required, but corresponding monitoring can also be performed after beam splitting on the main interference beam (316)).

[0046] Example 5 (see FIG5 ): The detailed implementation steps of a wavefront splitting interferometer comprising a single-pass / double-pass combined optical path structure with dispersion compensation and polarization splitting / combining, optical rotation processing of a reference beam, and returning the reference beam along the original path include:

[0047] The selection of components, the parallel light source (301), the optical path deflector (304), the reference beam reflector (308) and the interference result detector assembly (306) are the same as those in Example 4; the PBS spectrometer (305) and the dispersion compensation PBS spectrometer (309) newly added in this embodiment need to be of exactly the same model (if the dispersion and delay can be strictly matched with the reference beam, it is also feasible to replace it with a single optical cube for light transmission). Here, we use a 25.4mm PBS light cube for polarization splitting, and select an optical adjustment frame that does not block the four light transmission surfaces as the installation base for each of them; select a 1 / 4λ glass slide (307) with a standard thickness (0.3mm~3mm), and select a hollow structure glass slide holder assembly that can rotate along the optical axis as the installation base for it; in addition, a pair of 1 / 2λ glass slides (302, 303) with the same base material thickness and material as the 1 / 4λ glass slide in the reference beam are added. , and a hollow structure glass slide mounting and adjustment bracket assembly that can rotate along the optical axis is selected as the installation basis (if a single optical cube is used for replacement, items 302, 303 and their mounting components are not required); in addition, a custom-made base that conforms to the schematic layout (Figure 5) is required as the basis for the installation of various components and assemblies;

[0048] Parameter requirements are the same as those specified in the fourth embodiment and the fifth solution implementation principle section of the summary of the invention.

[0049] For the adjustment process, see Example 3. Before executing the adjustment steps of Example 2, the polarization vector of the 1 / 2λ glass plate (302, 303) needs to be adjusted to be 45° with the polarization vector of the incident light beam; in addition, the transmission polarization vector of the PBS needs to be adjusted to be consistent with the polarization vector of the incident light beam; then, the various adjustments in Example 2 are performed.

[0050] In the specific implementations of the five aforementioned embodiments, devices with the same function but different types can be interchanged in different embodiments. Furthermore, the components installed on the primary and secondary interference beam sets can be interchanged and expanded to include more detector probes. Materials and assembly methods not described in the specific implementations can also be implemented based on the functions of the corresponding devices and known technologies, as well as the methods and materials described in the Summary of the Invention section, and are not intended to limit the materials and implementation methods used in the implementation. For example, the beam combining methods of Examples 2 to 5 can still use the blade prism reflector of Example 1 as the beam combining element and adjust the optical path to accommodate the angle of incidence. For high-reliability measurement applications, the optical path calibrated by the laser may be more suitable for using sunlight, starlight, or spontaneous radiation as the light source, thereby avoiding range violations and other issues associated with single-frequency and dual-frequency lasers. Therefore, researchers in this field do not need to rely on the inventor's specific implementation as the sole means of implementing the present invention. Without infringing on the inventor's relevant rights, researchers in this field should select appropriate components and methods for research and implementation based on the latest achievements of related industries, their own technical expertise, and their resource advantages. Industrial Applicability

[0051] The industrial applicability of the present invention is mainly reflected in: clear market demand. On the one hand, efficient and sensitive detection instruments are needed for the crystal orientation or polarization direction of materials, and the accuracy of the interferometer in this application can meet this demand and far exceeds the accuracy that can be obtained by other methods; on the other hand, the interferometer in this application is expected to open up new markets in new navigation or positioning systems, and has some performance parameters or technical indicators that AGPS or GPS do not have.

[0052] Secondly, in terms of raw materials and technical methods for equipment construction, all components of this invention are readily available on the market, requiring only the design and manufacture of some basic components. Furthermore, all data collected by this invention is accomplished through photoelectric sensors, facilitating integration with computer systems for subsequent computations and network processing.

[0053] Finally, in terms of cost-effectiveness, while the present invention utilizes the same components as existing similar instruments or commonly available general optics, it possesses measurement capabilities not found in existing instruments, or offers superior performance, effectively promoting the development of social productivity.

Claims

1. A quasi-differential wavefront splitting dual-beam interferometer based on a planar optical path structure design, characterized by: A parallel light with a plane wave wavefront is used as a light source (001); an optical path deflector (002, 004) with a deflection angle of 90° is arranged at the same distance in front of the light beam emitted by the light source, and the light aperture of the optical path deflector (002, 004) needs to be smaller than half of the light aperture of the light source (001), and the spacing needs to be set to be smaller than the beam diameter of the light source (001) minus the effective measurement beam aperture, and is equidistantly distributed from the optical axis (OP) of the light source, and ensures that the reflected effective measurement beam 1 (013) and the effective measurement beam The two beams 2 (014) are coaxial and facing each other; a 90° knife-edge prism reflector is set on the axis of the light source as a deflection beam combiner (003), the center height of which is equal to or higher than the optical path deflector (002, 004) within 1 / 2 of the light aperture of the optical path deflector, and the angular bisector of its vertex angle is adjusted to coincide with the axis of the light source; an interference result detector component (007) is also set in the two light beam interference area in front of the two light beams after being deflected by the deflection beam combiner (003) to collect and measure the interference results and obtain the phase difference of the two effective measurement light beams.

2. Based on claim 1, the aforementioned optical path deflectors (002, 004) are replaced by a single rotationally symmetrical structure with an internally reflecting concave cone mirror having a vertex angle of 90°, and the deflecting beam combiner (003) is also replaced by a corresponding externally reflecting convex cone mirror, and the reflecting surfaces of the two groups of reflectors are set to the same height, or are set to a position where the effective light aperture of the deflecting beam combiner (003) includes at least 1% of the cross-section of each incident light beam.

3. An interferometer device based on a planar optical path structure design for differential wavefront splitting and semi-transparent and semi-reflective mirror beam combining, characterized by: A parallel light with a plane wave wavefront is used as a light source (101); optical path deflectors (102, 104) with a deflection angle of 90° are arranged at different distances in front of the light beam emitted by the light source, and the light aperture of the optical path deflectors (102, 104) needs to be smaller than half of the light aperture of the light source, and the spacing needs to be set to be smaller than the light source beam diameter minus the effective measurement beam aperture, and they are equidistantly distributed from the optical axis of the light source, and it is ensured that the reflected effective measurement beam 1 (113) and effective measurement beam 2 (114) are parallel and facing each other; at the same relative distance from the light source to the optical path deflector (102) and at the position of the axis of the light source, a An optical path deflector (103) with a deflection angle of 90° is provided, which is used to perform a 90° deflection on the effective measurement light beam 1 (113) so that the extended section (115) of the measurement light beam 1 after the deflection can maintain an orthogonal relationship with the effective measurement light beam 2 (114), so that they can converge at the interference beam combiner; a semi-transparent semi-reflective beam combiner (105) for interference beam combining is also provided on the axis of the light source at a distance equal to the distance of the optical path deflector (104) from the light source; one group of interference superposition light (116) of the interference light beam after the beam combination is transmitted to an interference result detector component (106) provided in front of the light beam for measurement, so as to obtain the phase difference between the two effective measurement light beams.

4. A wavefront splitting interferometer device based on a planar optical path structure design, having a pre-crossing region and a bent single-pass-dual-pass-common-mode combined optical path structure, characterized in that: A parallel light beam with a plane wave wavefront is used as a light source (201); light path deflectors (202, 204) with a deflection angle of 90° are arranged at different distances in front of the light beam emitted by the light source to split the light beam of the light source into an effective measurement light beam (214) and a common mode reference light beam (213); the light aperture of the light path deflectors (202, 204) needs to be smaller than half of the light aperture of the light source, and the spacing needs to be set to be smaller than the light source beam diameter minus the effective measurement beam aperture, and it is ensured that the reflected effective measurement beam (214) and the common mode reference beam (213) are parallel and in the same direction; a sample carrier (208) is arranged at the intersection of the light beam (211) in the area before passing through the light path deflector (202) and the effective measurement beam (214) ; an optical path deflector (203) with a deflection angle of 90° is arranged in the direction of travel of the common mode reference beam (213), so that the reference beam (215) after the second deflection can maintain an orthogonal relationship with the effective measurement beam (214); the vertical distance Lzr between the deflector (204) of the measurement light path and the deflector (202, 203) of the reference light path is set to half of the effective measurement beam length Lzm to achieve equal optical path design; a semi-transparent semi-reflective beam combiner (205) is arranged at the intersection of the effective reference beam 2 (215) and the effective measurement beam (214); one group (216) of the combined interference beams is directed to an interference result detector component (206) arranged in front of the beam for measurement to obtain the phase difference between the effective measurement beam and the effective reference beam.

5. A wavefront splitting interferometer device based on a planar optical path structure design, using a single-pass / double-pass combined optical path structure of polarization splitting / combining and optical rotation processing of a reference beam and returning the original path, characterized by: A linearly polarized parallel light with a plane wave wavefront is used as a light source (301); an optical path deflector (304) with a deflection angle of 90° is arranged directly in front of the light beam emitted by the light source; a thin-sheet polarization beam splitter (305) is installed at a position on the other part of the light path of the parallel light beam emitted by the light source and at a position with the same vertical distance from the light source as the optical path deflector (304), and the position is adjusted so that the vibration vector of the light beam emitted by the light source is consistent with the polarization direction required to pass through the PBS; a thin-sheet 1 / 4λ glass plate (307) is also installed in the path of the reference light beam, and the polarization vector of the glass plate is adjusted to be consistent with the reference light beam. The polarization vector of the incident light beam is in a 45° relationship; a front surface reflector (308) with a planar structure is installed after the effective reference light beam passes through the 1 / 4λ glass slide, and the mirror surface of the reflector is set to be parallel to the wavefront of the effective reference light beam, and the equivalent optical path of the spatial length Lmr+Ls / 2 passed by the effective reference light beam is set to be half of the effective measurement optical path Lmx+Ls / 2, that is, 2Lmr+Ls / 2=Lmx; an interference result detector component (306) is installed on the travel path of the combined interference light beam (316) to measure the phase difference between the effective measurement light beam and the effective reference light beam.

6. Based on claim 5, the thin-sheet polarization beam splitter (305) is replaced by a polarization beam splitter made of glass or crystal substrate, and the thin-sheet 1 / 4λ glass plate is replaced by a common 1 / 4λ glass plate with an optical substrate. In addition, a pair of 1 / 2λ glass plates (302, 303) with the same thickness and material as the 1 / 4λ glass plate in the reference beam and a PBS beam splitter (309) with completely consistent parameters with the beam combiner (305) are added to the measurement beam channel as dispersion compensation components. The two 1 / 2λ glass plates are respectively placed in front of and behind the optical path of the PBS beam splitter (309), and the polarization vector of the glass plate is kept at a 45° relationship with the vibration vector of the incident light beam. The transmission polarization vector of the PBS beam splitter (309) should be consistent with the polarization vector of its incident light beam, and the position of the reference beam reflector (308) with unequal optical path length is adjusted to keep the time for the same wavefront emitted by the light source in the initial state to reach the beam combiner or the interference result detector surface consistent.

7. A method for using the device according to claims 1 to 6, wherein the device is pre-adjusted to a posture unrelated to the measured object, and the initial phase difference of the device is read; then, the anisotropic light propagation medium of the light to be measured is filled or installed on the sample stage, or the effective measurement work area and the effective reference work area, or the posture of the device is adjusted so that the vector to be measured is parallel to the axis of the effective measurement light beam, and the measured phase difference of the device is read; and the anisotropic parameters of the measured object are obtained by calculating the phase difference variation obtained by performing a difference operation on the measured phase difference and the initial phase difference.

8. Based on claims 3-4, a set of auxiliary detectors (107, 207) are installed on the traveling wave optical path of the secondary interference light beam set (117, 217) after coherent beam combining using a semi-transparent and semi-reflective mirror to monitor the beam direction, beam quality, wavefront distortion, and spectral composition, which serve as reference signals for automatic calibration, evaluating the effectiveness of the detection results, and correcting assembly errors and parameter drifts.

9. Based on claims 1-6, the optical path deflector and the semi-transparent and semi-reflective mirror are installed on a motion mechanism that can move forward and backward along the axis of the effective light beam, so that the device has the ability to measure the spatial wavelength of the optical signal and detect the current phase.

10. Based on claims 1-6, the whole device is installed on a two-dimensional turntable such as a theodolite, so that the device has the functions of measuring spatial posture, completing automatic measurement and automatic calibration, and target tracking.

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