System for detecting optical path difference of prism of self-reference interferometer

Abstract

The invention provides a self-reference interferometer prism optical path difference detection system, which comprises a self-reference interferometer prism, a polarization splitting prism, a first reflector, a second reflector, a beam splitter prism, a first half-wave plate and a second half-wave plate, and is characterized in that the polarization splitting prism and the beam splitter prism are arranged below the self-reference interferometer prism; a white light source is arranged in front of the polarization splitting prism, and the first reflecting mirror is arranged behind the polarization splitting prism; a detector is arranged in front of the beam splitter prism, and the second reflector is arranged behind the beam splitter prism; the first half-wave plate is arranged on a light path between the polarization splitting prism and the self-reference interferometer prism, and the second half-wave plate is arranged on a light path between the polarization splitting prism and the first reflector. The self-reference interferometer prism optical path difference detection system provided by the invention can realize accurate measurement of the self-reference interferometer prism optical path difference.

Description

Technical Field

[0001] The invention relates to the technical field of optical measurement, and in particular to a self-reference interferometer prism optical path difference detection system. Background Art

[0002] In the phase grating position measurement system based on the principle of self-reference interference, after the grating diffracted light is split and reflected by the self-reference interferometer prism, the optical path of the propagation will no longer be equal, because the self-reference interferometer prism is made of two prisms glued together, resulting in an optical path difference, which will in turn cause a phase difference, resulting in an increase in the background light on the detector and a decrease in the contrast of the interference signal, which will ultimately have a significant impact on the measurement accuracy. Therefore, it is necessary to strictly control the optical path difference of the self-reference interferometer prism in the phase grating position measurement system, and use necessary methods to detect the optical path difference to ensure its measurement accuracy.

[0003] There are few existing methods for detecting the optical path difference of prisms, and the most common methods are to detect the optical path difference between the prism to be tested and the reference mirror. The self-reference interferometer prism is made of two prisms with special structures glued together. There is a light beam propagating in each of the two prisms. Each light beam propagates not only in the prism but also in the glue layer. Given the particularity of the structure of the self-reference interferometer prism, there is no detection system specifically used to detect the optical path difference of the self-reference interferometer prism in the prior art. Summary of the invention

[0004] The purpose of the present invention is to provide a self-referencing interferometer prism optical path difference detection system to solve the problem that there is no detection system specifically used for detecting the optical path difference of the self-referencing interferometer prism in the prior art, which leads to detection difficulties.

[0005] The present invention provides a self-reference interferometer prism optical path difference detection system, comprising a self-reference interferometer prism, a polarization beam splitter prism, a first reflector, a second reflector, a beam splitter prism, a first half-wave plate and a second half-wave plate, wherein the polarization beam splitter prism and the beam splitter prism are both arranged below the self-reference interferometer prism, a white light source is arranged in front of the polarization beam splitter prism, and the first reflector is arranged behind the polarization beam splitter prism; a detector is arranged in front of the beam splitter prism, and the second reflector is arranged behind the beam splitter prism; the first half-wave plate is arranged on the optical path between the polarization beam splitter prism and the self-reference interferometer prism, and the second half-wave plate is arranged on the optical path between the polarization beam splitter prism and the first reflector;

[0006] The polarization beam splitter prism is used to split the light emitted by the white light source into a first polarized light and a second polarized light. The first polarized light passes through the first half-wave plate and is vertically incident from the incident surface of the self-referencing interferometer prism. The second polarized light passes through the second half-wave plate and is reflected by the first reflector and the second reflector in sequence. The outgoing light of the second reflector and the outgoing light of the self-referencing interferometer prism are respectively incident on the beam splitter prism and reach the detector after being transmitted and reflected by the beam splitter prism.

[0007] According to a self-reference interferometer prism optical path difference detection system provided by the present invention, the light emitted by the white light source is vertically incident from the center of the front surface of the polarization beam splitter prism.

[0008] According to a self-referencing interferometer prism optical path difference detection system provided by the present invention, the first polarized light is emitted vertically from the upper surface of the polarization beam splitter prism, and the upper surface of the polarization beam splitter prism is parallel to the incident surface of the self-referencing interferometer prism.

[0009] According to a self-referencing interferometer prism optical path difference detection system provided by the present invention, the outgoing light of the self-referencing interferometer prism is vertically incident from the center of the upper surface of the beam splitter prism, and the upper surface of the beam splitter prism is parallel to the incident surface of the self-referencing interferometer prism.

[0010] According to a self-reference interferometer prism optical path difference detection system provided by the present invention, the second polarized light is emitted vertically from the rear surface of the polarization splitter prism, and the outgoing light of the second reflector is incident vertically from the center of the rear surface of the splitter prism.

[0011] According to a self-reference interferometer prism optical path difference detection system provided by the present invention, the incident light of the first reflector forms an angle of 45° with the first reflector, and the incident light of the second reflector forms an angle of 45° with the second reflector, so that the incident light of the first reflector and the outgoing light of the second reflector are parallel to each other.

[0012] According to a self-referencing interferometer prism optical path difference detection system provided by the present invention, the outgoing light of the second reflector and the outgoing light of the self-referencing interferometer prism meet in the beam splitter prism and respectively undergo transmission and reflection to form overlapping outgoing light.

[0013] According to a self-reference interferometer prism optical path difference detection system provided by the present invention, the initial position of the first half-wave plate is perpendicular to the incident direction of the first polarized light, and the initial position of the second half-wave plate is perpendicular to the incident direction of the second polarized light.

[0014] A self-reference interferometer prism optical path difference detection system provided by the present invention also includes a movable platform, and the first reflector and the second reflector are both installed on the movable platform.

[0015] According to a self-reference interferometer prism optical path difference detection system provided by the present invention, the self-reference interferometer prism is composed of a first prism and a second prism, and a polarization splitting film is plated between the first polarization splitting surface of the first prism and the second polarization splitting surface of the second prism and glued together to form a glue layer.

[0016] The self-reference interferometer prism optical path difference detection system provided by the present invention utilizes the Mach-Zehnder interference principle and can respectively measure the optical paths of two prisms in the self-reference interferometer through a special arrangement of the self-reference interferometer prism, the polarization beam splitter prism, the first reflector, the second reflector, the beam splitter prism, the first half-wave plate and the second half-wave plate. Since the light source adopts a white light source, the position of the zero optical path difference can be accurately determined by observing the white light interference fringes on the detector, and then the accurate measurement of the optical path difference of the self-reference interferometer prism is realized through calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a structural schematic diagram of the self-reference interferometer prism optical path difference detection system of the present invention;

[0019] Figure 2 It is a front view of a self-reference interferometer prism in the self-reference interferometer prism optical path difference detection system of the present invention;

[0020] Figure 3 It is a left view of a self-reference interferometer prism in the self-reference interferometer prism optical path difference detection system of the present invention;

[0021] Figure 4 It is a top view of the self-reference interferometer prism in the self-reference interferometer prism optical path difference detection system of the present invention.

[0022] Description of reference numerals:

[0023] SRI1, first prism; 101, roof surface 1; 102, roof surface 2; 103a, bottom surface 1; 103b, exit surface; 104, polarization splitting surface 1;

[0024] SRI2, second prism; 201, roof surface three; 202, roof surface four; 203, bottom surface two; 204, polarization splitting surface two; 205, incident surface; 300, bonding layer;

[0025] 400, polarization light zero; 401, polarization light one; 402, polarization light two; 403, polarization light three; 404, polarization light four; 405, polarization light five; 406, polarization light six; 407, polarization light seven;

[0026] S1, white light source; PBS, polarization beam splitter; HW1, first half-wave plate; HW2, second half-wave plate; M1, first reflector; M2, second reflector; BS, beam splitter; D1, detector; UDP, translation stage. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0029] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] like Figure 1As shown, the self-reference interferometer prism optical path difference detection system of the embodiment of the present invention includes a self-reference interferometer prism, a polarization beam splitter prism PBS, a first reflector M1, a second reflector M2, a beam splitter prism BS, a first half-wave plate HW1 and a second half-wave plate HW2. The polarization beam splitter prism PBS and the beam splitter prism BS are both arranged below the self-reference interferometer prism. A white light source S1 is arranged in front of the polarization beam splitter prism PBS, and the first reflector M1 is arranged behind the polarization beam splitter prism PBS. A detector D1 is arranged in front of the beam splitter prism BS, and the second reflector M2 is arranged behind the beam splitter prism BS. The first half-wave plate HW1 is arranged on the optical path between the polarization beam splitter prism PBS and the self-reference interferometer prism, and the second half-wave plate HW2 is arranged on the optical path between the polarization beam splitter prism PBS and the first reflector M1.

[0031] The polarization beam splitter prism PBS is used to split the light emitted by the white light source S1 into a first polarized light and a second polarized light. The first polarized light passes through the first half-wave plate HW1 and is vertically incident from the incident surface of the self-reference interferometer prism. The second polarized light passes through the second half-wave plate HW2 and is reflected by the first reflector M1 and the second reflector M2 in sequence. The polarization state of the first polarized light can be changed by adjusting the first half-wave plate HW1, and the polarization state of the second polarized light can be changed by adjusting the second half-wave plate HW2. The outgoing light of the second reflector M2 and the outgoing light of the self-reference interferometer prism are respectively incident on the beam splitter prism BS, and reach the detector D1 after being transmitted and reflected by the beam splitter prism BS.

[0032] During detection, it is necessary to measure the optical path of the two prisms in the self-reference interferometer prism respectively, and synchronously adjust the first reflector M1 and the second reflector M2 to move during the measurement process until an image with white interference fringes in the middle and colored interference fringes on both sides is observed on the detector D1 during the two measurement processes, and obtain the displacement distance of the first reflector M1 or the second reflector M2 relative to the initial position after the two adjustments, and then the optical path difference of the self-reference interferometer prism can be calculated by the optical path difference calculation formula.

[0033] Therefore, the self-referencing interferometer prism optical path difference detection system of the embodiment of the present invention utilizes the Mach-Zehnder interference principle and can measure the optical paths of the two prisms in the self-referencing interferometer respectively through the special arrangement of the self-referencing interferometer prism, the polarization beam splitter prism PBS, the first reflector M1, the second reflector M2, the beam splitter prism BS, the first half-wave plate HW1 and the second half-wave plate HW2. Since the light source adopts the white light source S1, the position of the zero optical path difference can be accurately determined by observing the white light interference fringes on the detector D1, and then the accurate measurement of the optical path difference of the self-referencing interferometer prism is realized through calculation.

[0034] Specifically, the self-reference interferometer prism optical path difference detection system also includes a movable platform UDP, and the first reflector M1 and the second reflector M2 are both mounted on the movable platform UDP. The displacement platform UDP adopts a nanometer-level ultra-precision displacement platform, which can move back and forth along the incident light direction of the first reflector M1, thereby realizing the synchronous position adjustment of the first reflector M1 and the second reflector M2.

[0035] Specifically, the detector D1 is a color stripe image detector, so stripes of different colors can be observed through the detector D1.

[0036] like Figure 2 As shown, the self-referencing interferometer prism is composed of a first prism SRI1 and a second prism SRI2, wherein the first prism SRI1 includes a ridge surface 101, a ridge surface 202, a bottom surface 103a, an exit surface 103b and a polarization splitting surface 104, and the second prism SRI2 includes a ridge surface 3 201, a ridge surface 4 202, a bottom surface 203, a polarization splitting surface 204 and an incident surface 205, wherein a polarization splitting film is coated between the polarization splitting surface 104 and the polarization splitting surface 204 and glued together to form a bonding layer 300.

[0037] The polarized light 0 400 is incident from the incident surface 205, and is divided into the polarized light 1 401 of the transmission part and the polarized light 2 402 of the reflection part by the polarized light splitting surface 204, and is incident on the first prism SRI1 and the second prism SRI2 respectively, wherein the polarized light 1 401 is reflected by the ridge surface 101, the bottom surface 103a, and the ridge surface 2 102 in sequence to obtain the polarized light 3 403, and is incident on the polarized light splitting surface 104 again, and is reflected by the polarized light splitting surface 104 and is emitted from the exit surface 103b to obtain the polarized light 5 405. The polarized light 2 402 is reflected by the ridge surface 3 201, the bottom surface 203, and the ridge surface 4 202 in sequence to obtain the polarized light 4 404, and is incident on the polarized light splitting surface 204 again, and is transmitted by the polarized light splitting surface 204 and is emitted from the exit surface 103b to obtain the polarized light 6 406. Polarized light five 405 and polarized light six 406 are synthesized into polarized light seven 407 .

[0038] like Figure 3 As shown, polarized light 1 401 is reflected by ridge surface 101, bottom surface 103a, and ridge surface 2 102 in sequence, and is incident on polarization splitting surface 104 again in a vertical downward direction. After being reflected by polarization splitting surface 104, it is emitted in a direction perpendicular to the emission surface 103b.

[0039] like Figure 4As shown, polarized light 2 402 is reflected by roof surface 3 201, bottom surface 203, and roof surface 4 202 in sequence, and is incident on polarization splitting surface 2 204 again in a horizontal left direction. After being transmitted through polarization splitting surface 204, it is emitted in a direction perpendicular to the exit surface 103b.

[0040] The polarization direction of polarized light zero 400 forms an angle of 45° with the P polarization direction of the polarization splitting surface, and the polarization directions of polarized light one 401 and polarized light two 402 are respectively parallel and perpendicular to the incident plane formed by polarized light zero 400 and the polarization splitting surface. After being reflected by the first prism SRI1 and the second prism SRI2, the polarization directions of polarized light one 401 and polarized light two 402 are rotated by 90°, and are coaxially emitted as polarized light five 405 and polarized light six 406, and are synthesized into polarized light seven 407.

[0041] When the polarization splitting surface 104 of the first prism SRI1 and the polarization splitting surface 204 of the second prism SRI2 are coated with polarization splitting films, the path l2 of the light in the second prism SRI2 is: AB→BC→CD→DE→EF→FL→LM, wherein AB is polarization light zero 400, BC is polarization light two 402, CD is the reflected light transmitted from the ridge surface three 201 to the bottom surface two 203, DE is the reflected light transmitted from the bottom surface two 203 to the ridge surface four 202, EF is polarization light four 404, FL is the light transmitted in the bonding layer, and LM is polarization light six 406. The path l1 of the light in the first prism SRI1 is: AB→BG→GH→HI→IJ→JK→KM, wherein AB is polarization zero 400, BG is the light transmitted in the bonding layer, GH is polarization one 401, HI is the reflected light transmitted from the ridge surface one 101 to the bottom surface one 103a, IJ is the reflected light transmitted from the bottom surface one 103a to the ridge surface two 102, JK is polarization three 403, and KM is polarization five 405.

[0042] Specifically, when installing the self-reference interferometer prism, it is necessary to adjust and determine the position where the incident light enters the self-reference interferometer prism. When the incident light of the self-reference interferometer prism is 45° linearly polarized light, the light propagates in both the first prism SRI1 and the second prism SRI2. By adjusting the position of the self-reference interferometer prism until the exit spots of polarized light five 405 and polarized light six 406 coincide, it can be determined that this position is the position where the incident light enters the self-reference interferometer prism.

[0043] Specifically, the light emitted by the white light source S1 is vertically incident from the center of the front surface of the polarization beam splitter prism PBS, wherein the first polarized light is vertically emitted from the upper surface of the polarization beam splitter prism PBS, and the upper surface of the polarization beam splitter prism PBS is parallel to the incident surface 205 of the self-reference interferometer prism.

[0044] The outgoing light of the self-referencing interferometer prism is vertically incident from the exact center of the upper surface of the beam splitter prism BS, and the upper surface of the beam splitter prism BS is parallel to the incident surface 205 of the self-referencing interferometer prism.

[0045] The second polarized light is vertically emitted from the exact center of the rear surface of the polarization beam splitter prism PBS, and the outgoing light of the second reflector M2 is vertically incident from the exact center of the rear surface of the beam splitter prism BS.

[0046] Specifically, the incident light of the first reflector M1 forms an angle of 45° with the first reflector M1, and the incident light of the second reflector M2 forms an angle of 45° with the second reflector M2, so that the incident light of the first reflector M1 and the outgoing light of the second reflector M2 are parallel to each other.

[0047] Specifically, the outgoing light from the second reflector M2 and the outgoing light from the self-referencing interferometer prism meet in the beam splitter prism BS and are respectively transmitted and reflected to form overlapping outgoing light, and then reach the detector D1.

[0048] Specifically, the first polarized light separated by the polarization beam splitter prism PBS from the white light source S1 is S polarized light, and the second polarized light separated by the polarization beam splitter prism PBS from the white light source S1 is P polarized light. The initial position of the first half-wave plate HW1 is perpendicular to the incident direction of the first polarized light, and the initial position of the second half-wave plate HW2 is perpendicular to the incident direction of the second polarized light. Then, in the subsequent detection process, the angles of the first half-wave plate HW1 and the second half-wave plate HW2 are adjusted according to actual needs.

[0049] The measurement process of the self-reference interferometer prism optical path difference detection system of the embodiment of the present invention is as follows:

[0050] The optical path where the first reflector M1 and the second reflector M2 are located is set as the reference optical path, and the optical path where the first prism SRI1 and the second prism SRI2 are located is set as the measurement optical path.

[0051] When measuring the optical path of the first prism SRI1 in the self-reference interferometer prism, in the measuring optical path, the first half-wave plate HW1 is adjusted so that the fast axis of the first half-wave plate HW1 forms an angle of 45° with the vibration direction of the first polarized light, and the first polarized light is converted into P polarized light after passing through the first half-wave plate HW1, and then enters the self-reference interferometer prism. Among them, the incident light enters the second prism SRI2 vertically from the incident surface 205, and enters the first prism SRI1 after being transmitted through the polarization splitting surface 204 of the second prism SRI2. In an ideal state, after three reflections, the polarized light 3 403 is completely converted into S polarized light, and is emitted after being reflected by the polarization splitting surface 1 104 of the first prism SRI1, that is, the polarized light 5 405. However, due to the influence of the bonding layer, the small polarization extinction of the polarization splitting film and the processing error, a part of the polarized light 403 is still P polarized light, which is transmitted through the polarization splitting plane 104 of the first prism SRI1 and then emitted through the incident plane 205 of the second prism SRI2 and enters the splitting prism BS. The measurement method uses this stray light to measure the optical path difference.

[0052] In the reference optical path, the second half-wave plate HW2 is adjusted so that the fast axis of the second half-wave plate HW2 forms an angle of 0° with the vibration direction of the second polarized light. Then, the second polarized light is still P polarized light after passing through the second half-wave plate HW2, and then enters the beam splitter prism BS after being reflected by the first reflector M1 and the second reflector M2 in sequence.

[0053] That is, the two beams of P polarized light emitted by the second reflector M2 and the self-reference interferometer prism are transmitted and reflected by the beam splitter BS and then reach the detector D1. During the detection process, the displacement stage UDP is adjusted to move forward and backward along the direction of the incident light of the first reflector M1 until an image with white interference fringes in the middle and colored interference fringes on both sides is observed on the detector D1. At this time, the displacement distance L1 of the displacement stage UDP from its initial position is obtained.

[0054] When measuring the optical path of the second prism SRI2 in the self-reference interferometer prism, in the measuring optical path, the first half-wave plate HW1 is adjusted so that the fast axis of the first half-wave plate HW1 forms an angle of 0° with the vibration direction of the first polarized light, and the first polarized light is still S polarized light after passing through the first half-wave plate HW1, and then enters the self-reference interferometer prism. Among them, the incident light enters the second prism SRI2 vertically from the incident surface 205, and then reflects through the polarization splitting surface 204 of the second prism SRI2. In an ideal state, after three reflections, the polarized light 404 is completely converted into P polarized light and is transmitted through the polarization splitting surface 204 of the second prism SRI2 and then emitted. However, due to the influence of the bonding layer, the small polarization extinction of the polarization splitting film and the processing error, a part of the polarized light 404 is still S polarized light, which is reflected by the polarization splitting plane 204 of the second prism SRI2 and then emitted through the incident plane 205 to enter the splitting prism BS. The measurement method uses this stray light to measure the optical path difference.

[0055] In the reference optical path, the second half-wave plate HW2 is adjusted so that the fast axis of the second half-wave plate HW2 forms an angle of 45° with the vibration direction of the second polarized light. Then, the second polarized light becomes S polarized light after passing through the second half-wave plate HW2, and then enters the beam splitter prism BS after being reflected by the first reflector M1 and the second reflector M2 in sequence.

[0056] That is, the two beams of S polarized light emitted by the second reflector M2 and the self-reference interferometer prism are transmitted and reflected by the beam splitter BS and then reach the detector D1. During the detection process, the displacement stage UDP is adjusted to move forward and backward along the direction of the incident light of the first reflector M1 until an image with white interference fringes in the middle and colored interference fringes on both sides is observed on the detector D1. At this time, the displacement distance L2 of the displacement stage UDP from its initial position is obtained.

[0057] Then, the optical path difference of the self-reference interferometer prism is calculated using the optical path difference calculation formula. That is, the difference between L2 and L1 is first calculated, and then the difference is multiplied by the refractive index of the light to obtain the optical path difference of the self-reference interferometer prism.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-reference interferometer prism optical path difference detection system, characterized in that: The invention comprises a self-referencing interferometer prism, a polarization beam splitter prism, a first reflector, a second reflector, a beam splitter prism, a first half-wave plate and a second half-wave plate, wherein the polarization beam splitter prism and the beam splitter prism are both arranged below the self-referencing interferometer prism, a white light source is arranged in front of the polarization beam splitter prism, and the first reflector is arranged behind the polarization beam splitter prism; a detector is arranged in front of the beam splitter prism, and the second reflector is arranged behind the beam splitter prism; the first half-wave plate is arranged on the optical path between the polarization beam splitter prism and the self-referencing interferometer prism, and the second half-wave plate is arranged on the optical path between the polarization beam splitter prism and the first reflector; The polarization beam splitter prism is used to split the light emitted by the white light source into a first polarized light and a second polarized light. The first polarized light passes through the first half-wave plate and is vertically incident from the incident surface of the self-referencing interferometer prism. The second polarized light passes through the second half-wave plate and is reflected by the first reflector and the second reflector in sequence. The outgoing light of the second reflector and the outgoing light of the self-referencing interferometer prism are respectively incident on the beam splitter prism and reach the detector after being transmitted and reflected by the beam splitter prism.

2. The self-reference interferometer prism optical path difference detection system according to claim 1, characterized in that: The light emitted by the white light source is vertically incident from the center of the front surface of the polarization beam splitter prism.

3. The self-reference interferometer prism optical path difference detection system according to claim 1, characterized in that: The first polarized light is emitted vertically from the upper surface of the polarization beam splitter prism, and the upper surface of the polarization beam splitter prism is parallel to the incident surface of the self-reference interferometer prism.

4. The self-reference interferometer prism optical path difference detection system according to claim 1, characterized in that: The outgoing light of the self-referencing interferometer prism is vertically incident from the exact center of the upper surface of the beam splitter prism, and the upper surface of the beam splitter prism is parallel to the incident surface of the self-referencing interferometer prism.

5. The self-reference interferometer prism optical path difference detection system according to claim 1, characterized in that: The second polarized light is vertically emitted from the rear surface of the polarization beam splitter prism, and the outgoing light of the second reflector is vertically incident from the exact center of the rear surface of the beam splitter prism.

6. The self-reference interferometer prism optical path difference detection system according to claim 1, characterized in that: The incident light of the first reflector forms an angle of 45° with the first reflector, and the incident light of the second reflector forms an angle of 45° with the second reflector, so that the incident light of the first reflector and the outgoing light of the second reflector are parallel to each other.

7. The self-reference interferometer prism optical path difference detection system according to claim 1, characterized in that: The outgoing light of the second reflector and the outgoing light of the self-reference interferometer prism meet in the beam splitter prism and are respectively transmitted and reflected to form overlapping outgoing light.

8. The self-reference interferometer prism optical path difference detection system according to claim 1, characterized in that: An initial position of the first half-wave plate is perpendicular to an incident direction of the first polarized light, and an initial position of the second half-wave plate is perpendicular to an incident direction of the second polarized light.

9. The self-reference interferometer prism optical path difference detection system according to claim 1, characterized in that: It also includes a movable platform, on which the first reflector and the second reflector are both mounted.

10. The self-reference interferometer prism optical path difference detection system according to claim 1, characterized in that: The self-reference interferometer prism consists of a first prism and a second prism, wherein a polarization splitting film is plated between a first polarization splitting surface of the first prism and a second polarization splitting surface of the second prism and the surfaces are glued together to form a glue layer.

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