A self-referencing interferometer prism optical path difference detection system

Abstract

The present invention provides a self-referencing interferometer prism optical path difference detection system, comprising 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. The polarization beam splitter prism and the beam splitter prism are both arranged below the self-referencing interferometer prism. A white light source is provided in front of the polarization beam splitter prism, and the first reflector is arranged behind the polarization beam splitter prism. A detector is provided 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 self-referencing interferometer prism optical path difference detection system provided by the present invention can achieve accurate measurement of the optical path difference of the self-referencing interferometer prism.

Description

Technical Field

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

[0002] In a phase grating position measurement system based on the principle of self-referencing interferometry, the grating diffracted light is split and reflected by the self-referencing interferometer prism. Since the self-referencing interferometer prism is composed of two prisms glued together, the optical path lengths of the light propagating will no longer be equal, resulting in an optical path difference. This in turn causes a phase difference, resulting in increased background light on the detector and decreased contrast of the interference signal, ultimately significantly affecting measurement accuracy. Therefore, it is necessary to strictly control the optical path difference of the self-referencing interferometer prism in phase grating position measurement systems and adopt necessary methods to detect the optical path difference to ensure its measurement accuracy.

[0003] Existing methods for measuring prism optical path difference are limited; the most common method involves measuring the optical path difference between the prism under test and a reference mirror. A self-referencing interferometer prism is composed of two prisms bonded together, each with a single beam propagating through it. Each beam propagates not only through the prisms but also through the bonded layer. Given the unique structure of a self-referencing interferometer prism, no system specifically designed for measuring its optical path difference exists. 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 the prior art has no detection system specifically used for detecting the optical path difference of the self-referencing interferometer prism, resulting in detection difficulties.

[0005] The present invention provides a self-referencing interferometer prism optical path difference detection system, comprising 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 provided in front of the polarization beam splitter prism, and the first reflector is provided behind the polarization beam splitter prism; a detector is provided in front of the beam splitter prism, and the second reflector is provided behind the beam splitter prism; the first half-wave plate is provided on the optical path between the polarization beam splitter prism and the self-referencing interferometer prism, and the second half-wave plate is provided on the optical path between the polarization beam splitter prism and the self-referencing interferometer prism;

[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 in sequence by the first reflector and the second reflector. The outgoing light of the second reflector and the outgoing light of the self-referencing interferometer prism respectively enter the beam splitter prism and reach the detector after being transmitted and reflected by the beam splitter prism respectively.

[0007] According to the 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-referencing 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 beam splitter prism, and the outgoing light of the second reflector is vertically incident from the center of the rear surface of the beam splitter prism.

[0011] According to a self-referencing 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 intersect in the beam splitter prism and respectively undergo transmission and reflection to form overlapping outgoing light.

[0013] According to a self-referencing 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] According to the present invention, a self-reference interferometer prism optical path difference detection system further includes a movable platform, and the first reflector and the second reflector are both installed on the movable platform.

[0015] According to a self-referencing interferometer prism optical path difference detection system provided by the present invention, the self-referencing interferometer prism is composed of a first prism and a second prism, and a polarization splitting film is coated 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 bonding layer.

[0016] The self-referencing interferometer prism optical path difference detection system provided by the present invention utilizes the Mach-Zehnder interference principle and can measure the optical path of two prisms in the self-referencing interferometer respectively through a special arrangement of the self-referencing 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 zero optical path difference can be accurately determined by observing the white light interference fringes on the detector, and then the precise measurement of the optical path difference of the self-referencing interferometer prism is achieved through calculation. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0018] Figure 1 Schematic diagram of the structure of the self-reference interferometer prism optical path difference detection system of the present invention;

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

[0021] Figure 4 This 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 zero; 401, polarization one; 402, polarization two; 403, polarization three; 404, polarization four; 405, polarization five; 406, polarization six; 407, polarization 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 following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts 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 to indicate directions or positional relationships based on the directions 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 device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said 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 an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0030] like Figure 1As shown, the self-referencing interferometer prism optical path difference detection system of an embodiment of the present invention includes a self-referencing 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-referencing interferometer prism. A white light source S1 is provided in front of the polarization beam splitter prism PBS, and the first reflector M1 is provided behind the polarization beam splitter prism PBS. A detector D1 is provided in front of the beam splitter prism BS, and the second reflector M2 is provided behind the beam splitter prism BS. The first half-wave plate HW1 is provided in the optical path between the polarization beam splitter prism PBS and the self-referencing interferometer prism, and the second half-wave plate HW2 is provided in 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 white light source S1 into first and second polarized light. The first polarized light passes through the first half-wave plate HW1 and is incident perpendicularly on the incident plane of the self-referencing interferometer prism. The second polarized light passes through the second half-wave plate HW2 and is reflected sequentially by the first and second mirrors M1 and M2. 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 light emitted from the second reflector M2 and the light emitted from the self-referencing interferometer prism are respectively incident on the beam splitter prism BS, and then respectively transmitted and reflected by the beam splitter prism BS before reaching the detector D1.

[0032] During detection, it is necessary to measure the optical path of the two prisms in the self-reference interferometer prism separately, 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. Then, the optical path difference of the self-reference interferometer prism can be calculated using 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 path of the two prisms in the self-referencing interferometer respectively through the special arrangement of the self-referencing interferometer prism, polarization beam splitter prism PBS, first reflector M1, second reflector M2, beam splitter prism BS, first half-wave plate HW1 and second half-wave plate HW2. Since the light source adopts white light source S1, the position of 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 achieved through calculation.

[0034] Specifically, the self-referencing interferometer prism optical path difference detection system also includes a movable platform UDP, on which the first reflector M1 and the second reflector M2 are mounted. This platform UDP utilizes a nanometer-scale ultra-precision platform capable of moving back and forth along the direction of the incident light on the first reflector M1, thereby achieving synchronous position adjustment of the first and second reflectors M1, 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 consists 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 output surface 103b and a polarization splitting surface 104, and the second prism SRI2 includes a ridge surface 301, a ridge surface 402, 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] Polarized light 0 400 is incident on incident surface 205, and is split by polarization splitting surface 204 into a transmitted polarized light 1 401 and a reflected polarized light 2 402. These polarized light 1 401 then enters first prism SRI1 and second prism SRI2, respectively. Polarized light 1 401 is sequentially reflected by roof surface 101, bottom surface 103a, and roof surface 2 102 to produce polarized light 3 403. Polarized light 1 401 is then incident on polarization splitting surface 104 again, reflected by polarization splitting surface 104, and then emitted from exit surface 103b to produce polarized light 5 405. Polarized light 2 402 is then sequentially reflected by roof surface 3 201, bottom surface 203, and roof surface 4 202 to produce polarized light 4 404. Polarized light 2 402 is then incident on polarization splitting surface 204 again, transmitted by polarization splitting surface 204, and then emitted from exit surface 103b to produce polarized light 6 406. Polarized light five 405 and polarized light six 406 are combined into polarized light seven 407 .

[0038] like Figure 3 As shown, polarized light 401 is reflected by roof surface 101, bottom surface 103a, and roof 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 exit 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 0 400 forms a 45° angle with the P polarization direction of the polarization splitting plane. Polarized light 1 401 and polarized light 2 402 are polarized parallel and perpendicular, respectively, to the incident plane formed by polarized light 0 400 and the polarization splitting plane. After reflection from the first prism SRI1 and the second prism SRI2, polarized light 1 401 and polarized light 2 402 undergo a 90° rotation in their polarization directions, exiting coaxially as polarized light 5 405 and polarized light 6 406, which combine to form polarized light 7 407.

[0041] After 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, where AB is polarization zero 400, BC is polarization 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 four 404, FL is the light transmitted in the adhesive layer, and LM is polarization six 406. The path l1 of the light in the first prism SRI1 is: AB→BG→GH→HI→IJ→JK→KM, where AB is polarization zero 400, BG is the light transmitted in the adhesive 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-referencing interferometer prism, it is necessary to adjust and determine the position at which the incident light enters the self-referencing interferometer prism. When the incident light into the self-referencing interferometer prism is 45° linearly polarized light, the light propagates through both the first prism SRI1 and the second prism SRI2. By adjusting the position of the self-referencing interferometer prism until the exit spots of polarized light 5 405 and polarized light 6 406 coincide, it can be determined that this position is the position at which the incident light enters the self-referencing 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. The first polarized light is vertically emitted from the upper surface of the polarization beam splitter prism PBS, which is parallel to the incident surface 205 of the self-referencing interferometer prism.

[0044] The outgoing light of the self-referencing interferometer prism is vertically incident from the 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 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 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 intersect in the beam splitter prism BS and are respectively transmitted and reflected to form overlapping outgoing light, which then reaches the detector D1.

[0048] Specifically, the first polarized light generated by the white light source S1 after passing through the polarization beam splitter prism PBS is S-polarized light, and the second polarized light generated by the white light source S1 after passing through the polarization beam splitter prism PBS 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. The angles of the first and second half-wave plates HW1 and HW2 are then adjusted according to actual needs during subsequent testing.

[0049] The measurement process of the self-referencing interferometer prism optical path difference detection system according to 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 a self-referencing interferometer, the first half-wave plate HW1 is adjusted in the measurement optical path so that its fast axis forms a 45° angle with the vibration direction of the first polarized light. This converts the first polarized light into P-polarized light after passing through the first half-wave plate HW1 and then enters the self-referencing interferometer prism. Incident light enters the second prism SRI2 perpendicularly from the incident plane 205, passes through the second polarization splitting plane 204 of the second prism SRI2, and then enters the first prism SRI1. Ideally, after three reflections, polarization 3 403 is completely converted to S-polarized light, which then reflects through the first polarization splitting plane 104 of the first prism SRI1 and emerges as polarization 5 405. However, due to the influence of the adhesive layer, the small polarization extinction of the polarization splitting film, and processing errors, a portion of the polarized light 403 is still P-polarized light. After being transmitted through the polarization splitting plane 104 of the first prism SRI1, it is emitted through the incident plane 205 of the second prism SRI2 and enters the splitter prism BS. This 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 remains 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] Specifically, the two beams of P-polarized light emitted by the second reflector M2 and the self-referencing interferometer prism are transmitted and reflected by the beamsplitter BS, respectively, before arriving at detector D1. During the detection process, the translation stage UDP is adjusted to move back and forth along the direction of the incident light from the first reflector M1 until an image with white interference fringes in the center and colored interference fringes on the sides is observed on detector D1. At this point, the displacement distance L1 of the translation stage UDP from its initial position is determined.

[0054] When measuring the optical path of the second prism SRI2 in the self-referencing interferometer prism, the first half-wave plate HW1 is adjusted in the measurement optical path so that its fast axis forms a 0° angle with the vibration direction of the first polarized light. This allows the first polarized light to remain S-polarized after passing through the first half-wave plate HW1 and then enter the self-referencing interferometer prism. Incident light enters the second prism SRI2 perpendicularly from the incident surface 205 and is then reflected by the second polarization splitting surface 204 of the second prism SRI2. Ideally, after three reflections, the polarized light 404 is completely converted to P-polarized light, which then transmits through the second polarization splitting surface 204 of the second prism SRI2 and exits. However, due to the influence of the adhesive layer, the small polarization extinction of the polarization splitting film, and processing errors, a portion of the polarized light 404 is still S-polarized light. After being reflected by the polarization splitting surface 204 of the second prism SRI2, it is emitted through the incident surface 205 and enters the splitting prism BS. This 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] Specifically, the two beams of S-polarized light emitted by the second reflector M2 and the self-referencing interferometer prism are transmitted and reflected by the beamsplitter BS, respectively, before arriving at detector D1. During the detection process, the translation stage UDP is adjusted to move back and forth along the direction of the incident light from the first reflector M1 until an image with white interference fringes in the center and colored interference fringes on the sides is observed on detector D1. At this point, the displacement distance L2 of the translation stage UDP from its initial position is determined.

[0057] Then, the optical path difference of the self-referencing 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 light to obtain the optical path difference of the self-referencing 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 above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with 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-referencing 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 reflecting mirror, a second reflecting mirror, 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 provided in front of the polarization beam splitter prism, and the first reflecting mirror is provided behind the polarization beam splitter prism; a detector is provided in front of the beam splitter prism, and the second reflecting mirror is provided behind the beam splitter prism; the first half-wave plate is provided on the optical path between the polarization beam splitter prism and the self-referencing interferometer prism, and the second half-wave plate is provided on the optical path between the polarization beam splitter prism and the first reflecting mirror; 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 in sequence by the first reflector and the second reflector. The outgoing light of the second reflector and the outgoing light of the self-referencing interferometer prism respectively enter the beam splitter prism and reach the detector after being transmitted and reflected by the beam splitter prism respectively.

2. The self-referencing 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-referencing 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-referencing interferometer prism.

4. The self-referencing 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-referencing 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 center of the rear surface of the beam splitter prism.

6. The self-referencing 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-referencing interferometer prism optical path difference detection system according to claim 1, characterized in that: The outgoing light from the second reflector and the outgoing light from the self-referencing interferometer prism meet in the beam splitter prism and form overlapping outgoing light through transmission and reflection respectively.

8. The self-referencing 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 the incident direction of the first polarized light, and an initial position of the second half-wave plate is perpendicular to the incident direction of the second polarized light.

9. The self-referencing interferometer prism optical path difference detection system according to claim 1, characterized in that: A movable platform is also included, and the first reflector and the second reflector are both mounted on the movable platform.

10. The self-referencing 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. 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 the two surfaces are glued together to form a glue layer.

Images