Holographic grating preparation system and preparation method

Abstract

The present disclosure relates to the technical field of holographic optical waveguide, and provides a holographic grating preparation system and a preparation method. The holographic grating preparation system comprises: a laser light source for generating a laser beam; a polarization light splitting component for splitting the laser beam into two beams and adjusting the light intensity and the beam polarization direction of the split laser beams, so that the polarization directions of the two split laser beams are perpendicular to the horizontal plane and parallel to the rotation axis of the mirror; a mirror group for mirror reflecting the split laser beams output by the polarization light splitting component to form two intersecting laser beams with a set angle, and the set angle is adjusted according to the rotation angle of the mirror group; and a recording medium for receiving the two intersecting laser beams, recording the interference fringes of the two intersecting laser beams through the refractive index and / or transmittance changes varying with the two intersecting laser beams, and forming a holographic grating.

Description

Technical Field

[0001] This disclosure relates to the field of holographic waveguide technology, and in particular to a holographic grating fabrication system and fabrication method. Background Technology

[0002] Holographic gratings have been applied in many fields, including displays. Among them, optical waveguides are the core components of AR (Augmented Reality) display technology. Holographic waveguides based on holographic gratings have advantages such as low cost, large size, and high diffraction efficiency, and represent an important development direction for optical waveguides.

[0003] Holographic gratings are fabricated using the principle of interference exposure. Specifically, interference fringes are generated by two beams of light intersecting at a designed angle in a recording medium and then recorded to form a holographic grating. The fabrication process of a holographic grating is extremely complex because it requires precise orientation adjustment of the two beams and that their polarization directions be identical. Summary of the Invention

[0004] In view of this, the present disclosure provides a holographic grating fabrication system and method to solve the problem of difficult optical path assembly and adjustment in the fabrication of holographic gratings in the prior art.

[0005] To achieve the above objectives, the technical solution adopted in this disclosure is:

[0006] On one hand, this disclosure provides a holographic grating fabrication system, which includes: a laser source for generating a laser beam; a polarization beam splitting component for splitting the laser beam into two beams and adjusting the intensity of the split laser beams, as well as adjusting the polarization direction of the beams so that the polarization directions of the two split laser beams are perpendicular to the horizontal plane and parallel to the rotation axis of the mirror.

[0007] A mirror assembly, including the mirrors, is used to reflect the split laser beam output from the polarization beam splitter to form two intersecting laser beams with a set angle, the set angle being adjusted according to the rotation angle of the mirror assembly; a recording medium receives the two intersecting laser beams and records the interference fringes of the two intersecting laser beams by varying the refractive index and / or transmittance as the two intersecting laser beams change, thus forming a holographic grating.

[0008] In one embodiment, the holographic grating fabrication system further includes a spot adjustment component, comprising a beam expander and an aperture, respectively disposed upstream and downstream of the optical path of the polarization beam splitter, for adjusting the diameter of the laser beam so that the spot sizes of the two intersecting laser beams are matched at the intersection.

[0009] In one embodiment, the holographic grating fabrication system further includes: an optical path compensation component disposed on the optical path of the laser beam, used to adjust the optical path of two intersecting laser beams having a set angle, such that the optical path difference between the two intersecting laser beams is a first value, wherein the two intersecting laser beams with an optical path difference of the first value can interfere; and / or, a refractive index compensation component disposed at the junction of the two intersecting laser beams, used to change the refractive index of the recording medium boundary, so that the two intersecting laser beams can enter the recording medium.

[0010] In one embodiment, the polarization beam splitter includes a first polarization beam splitter and a second polarization beam splitter connected sequentially in the optical path of the laser beam. Each of the first polarization beam splitter and the second polarization beam splitter includes a half-wave plate and a polarization beam splitter prism.

[0011] In one embodiment, the reflector assembly includes a first reflector and a second reflector disposed downstream of the optical path of the first polarization beam splitter, and a third reflector and a fourth reflector disposed downstream of the optical path of the second polarization beam splitter.

[0012] In one embodiment, the optical path compensation component is connected between the second polarization beam splitter and the recording medium.

[0013] In one embodiment, the refractive index compensation component includes a liquid refractive index compensation medium or a prism, and a refractive index matching liquid is disposed between the refractive index compensation component and the recording medium.

[0014] In one embodiment, the holographic grating fabrication system further includes: a mechanical adjustment frame, rotatably connected to the recording medium, for adjusting the three-dimensional position and three-axis rotation angle of the recording medium.

[0015] In one embodiment, the recording medium includes any one of a holographic plate, a dichromate gel, and a polymer film in roll or sheet form.

[0016] On the other hand, this disclosure provides a method for fabricating a holographic grating. The holographic grating is fabricated using the holographic grating fabrication system described above. The method includes: splitting a laser beam into two beams using a polarization beam splitter and adjusting the intensity and polarization direction of the split laser beams, such that the polarization directions of the two split laser beams are perpendicular to the horizontal plane and parallel to the rotation axis of a reflector, wherein the laser beams are generated by a laser source; using a reflector group to mirror-reflect the split laser beams output by the polarization beam splitter to form two intersecting laser beams with a set angle, the set angle being adjusted according to the rotation angle of the reflector group, wherein the reflector group includes the reflector; using an optical path compensation component to adjust the optical path of the two intersecting laser beams with the set angle, such that the optical path difference between the two intersecting laser beams is a first value, wherein the two intersecting laser beams with an optical path difference of the first value can interfere; using a recording medium to receive the interfering two intersecting laser beams, and recording the interference fringes of the two intersecting laser beams by varying the refractive index and / or transmittance as the two intersecting laser beams change, thereby forming a holographic grating.

[0017] The beneficial effects of this disclosed embodiment compared to the prior art are as follows: By using a polarization beam splitter to split a laser beam into two beams, and using a mirror group to adjust the angle of the split laser beams, and using an optical path compensation component to adjust the optical path of the split laser beams, the two split laser beams can form interference fringes and be recorded in the recording medium to form a holographic grating. During the grating recording process, this device allows the two beams to interfere at any angle by adjusting the polarization direction and setting the rotation angle of the mirrors, and makes the intensity of the two beams match the size of the light spot. The recording medium is matched with the direction of the holographic interference fringes by a six-axis turntable, realizing the decoupling of grating interference adjustment and recording grating direction adjustment, which greatly reduces the difficulty of adjusting the optical path in the grating recording device. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a holographic grating fabrication system provided in an embodiment of this disclosure;

[0020] Figure 2 This is a schematic diagram of another holographic grating fabrication system provided in this embodiment;

[0021] Figure 3This is a schematic flowchart of a holographic grating fabrication method according to an embodiment of the present disclosure. Detailed Implementation

[0022] To make the technical problems, technical solutions, and beneficial effects to be solved by this disclosure clearer, the disclosure will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining this disclosure and are not intended to limit this disclosure.

[0023] The holographic grating fabrication system according to embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings.

[0024] Figure 1 This is a schematic diagram of the structure of a holographic grating fabrication system provided in an embodiment of this disclosure; Figure 2 This is a schematic diagram of another holographic grating fabrication system provided in an embodiment of this disclosure. The following is a description of... Figure 1 and Figure 2 This describes the holographic grating fabrication system provided in the embodiments of this disclosure.

[0025] like Figure 1 As shown, this disclosure provides a holographic grating fabrication system, which includes:

[0026] Laser source 101 is used to generate laser beams. Specifically, the laser source can generate laser beams of different wavelengths.

[0027] The polarization beam splitter 102 is used to split the output beam of the laser beam assembly into two beams and adjust the light intensity and polarization direction of the split laser beams so that the polarization directions of the two split laser beams are perpendicular to the horizontal plane and parallel to the rotation axis of the reflector.

[0028] Specifically, the polarization beam splitter can split a laser beam emitted by a laser source into two laser beams with adjustable intensity and polarization directions perpendicular to the horizontal plane.

[0029] The reflector group 103 includes the aforementioned reflector and is used to reflect the polarized laser beam after beam splitting to form two intersecting laser beams with a set angle, which is adjusted according to the rotation angle of the reflector group.

[0030] Specifically, by passing one of the split laser beams through an optical path compensation component, the optical path of the two intersecting laser beams can be adjusted so that the optical path difference between the two intersecting laser beams is within the coherence length of the laser emitted by the laser, thereby allowing the two intersecting laser beams to interfere.

[0031] Recording medium 105 receives two intersecting laser beams that interfere with each other, and records the interference fringes of the two intersecting laser beams by varying the refractive index and / or transmittance as the two intersecting laser beams change, thus forming a holographic grating.

[0032] The technical solution of this disclosure provides a holographic grating fabrication optical path, which simplifies the fabrication process and makes the holographic grating fabrication system simple and easy to adjust. This holographic grating fabrication optical path can form two coherent beams with arbitrary angles at the recording medium, with the polarization direction always perpendicular to the horizontal plane, thereby causing interference between the two intersecting laser beams. After adjusting the angle between the normal vector of the recording medium and the interference beams, a holographic grating with grating vectors of arbitrary direction and length can finally be formed in the recording medium.

[0033] In the embodiments disclosed herein, such as Figure 2 As shown, the holographic grating fabrication system also includes a spot adjustment component, including a beam expander 221, an aperture 222, and an aperture 223. The beam expander is located upstream of the optical path of the polarization beam splitter, and the aperture is located downstream of the optical path of the polarization beam splitter. The beam expander is used to adjust the diameter of the laser beam so that the spot sizes of the two intersecting laser beams at the intersection are matched.

[0034] Specifically, adjusting the beam expander and the grating can change the spot size of two intersecting laser beams, so that the spot sizes of the two intersecting laser beams match at the intersection, thereby forming clearer interference fringes.

[0035] In the embodiments disclosed herein, such as Figure 2 As shown, the holographic grating fabrication system also includes an optical path compensation component 104 and a refractive index compensation component. The optical path compensation component 104 is disposed on the optical path of the laser beam and is used to adjust the optical path of two intersecting laser beams with a set angle, such that the optical path difference between the two intersecting laser beams is a first value, wherein the two intersecting laser beams with the first optical path difference can interfere.

[0036] The refractive index compensation component 250 is located at the junction of two intersecting laser beams to change the refractive index of the recording medium boundary, so that the two intersecting laser beams can enter the recording medium.

[0037] In the embodiments disclosed herein, such as Figure 2 As shown, the polarization beam splitter includes a first polarization beam splitter and a second polarization beam splitter connected sequentially in the optical path of the laser beam. The first polarization beam splitter includes a half-wave plate 231 and a polarization beam splitter prism 232, and the second polarization beam splitter includes a half-wave plate 233 and a polarization beam splitter prism 234.

[0038] In the embodiments disclosed herein, such as Figure 2As shown, the reflector assembly includes a first reflector 241 and a second reflector 242 disposed downstream of the optical path of the first polarization beam splitter, and a third reflector 243 and a fourth reflector 244 disposed downstream of the optical path of the second polarization beam splitter. Specifically, the first reflector 241, the second reflector 242, the third reflector 243, and the fourth reflector 244 are located in a horizontal plane and can move freely in two dimensions within the horizontal plane, and can rotate about an axis perpendicular to the horizontal plane. Two beams of light, meeting at any angle at any position within the horizontal plane, can be formed through the first reflector 241, the second reflector 242, the third reflector 243, and the fourth reflector 244.

[0039] In the embodiments disclosed herein, such as Figure 2 As shown, the optical path compensation component 104 can be connected between the second polarization beam splitter and the third reflector 243.

[0040] In the embodiments disclosed herein, such as Figure 2 As shown, the refractive index compensation component 250 can be a liquid refractive index compensation medium with a specific refractive index or a prism with a specific shape that contacts the recording medium. A refractive index matching liquid is provided in the gap between the refractive index compensation component and the recording medium to eliminate the gap between the refractive index compensation component and the recording medium.

[0041] By setting a refractive index compensation component with a specific shape and refractive index, the influence of total internal reflection can be eliminated, allowing two intersecting laser beams to enter the recording medium at any angle.

[0042] In this embodiment, the holographic grating fabrication system further includes a mechanical adjustment frame (not shown in the figure), which can be rotatably connected to the recording medium for adjusting the three-dimensional position and three-axis rotation angle of the recording medium. Specifically, the mechanical adjustment frame can perform three-dimensional movement and three-axis rotation in space, thereby driving the recording medium to move and changing the three-dimensional position of the recording medium in space and the orientation of the material normal vector in space. Thus, a holographic grating with arbitrary spatial orientation and arbitrary grating period can be formed in the recording medium by interfering with two beams of coherent light at arbitrary angles.

[0043] Specifically, in this embodiment, spatially continuous grating recording can be formed, thereby creating holographic gratings of arbitrary size. During the recording of holographic gratings, after one holographic grating has been exposed and recorded, the position of the recording medium can be adjusted to record a second holographic grating. Thus, spatially spliced ​​and superimposed holographic gratings can be formed in the recording medium through splicing or other methods. Furthermore, the wavelength of the coherent light can be changed to form spliced ​​and superimposed multicolor holographic gratings in the recording medium. To optimize production efficiency, the recording medium can be prepared as a roll material or a sheet recording medium can be fixed on a conveyor belt. For example, the recording medium can be a polymer film in roll or sheet form. After one grating has been exposed and recorded, the next sheet of recording medium material is introduced through the roll or conveyor belt for holographic grating exposure and recording, achieving continuous production.

[0044] like Figure 2 As shown, laser source 101 emits a coherent laser beam with a characteristic wavelength and arbitrary polarization direction. A first half-wave plate 231 rotates the laser's polarization direction by a specific angle θ1, and the beam is split into a beam B11 perpendicular to the horizontal plane and a beam B21 parallel to the horizontal plane by a first polarizing beam splitter 232. Beam B21, after passing through a second half-wave plate 233, has its polarization direction rotated by a specific angle θ2, and after passing through a second polarizing beam splitter 234, it is split into a beam B22 perpendicular to the horizontal plane and a beam B3 parallel to the horizontal plane. By adjusting θ1 and θ2, the light intensity of beams B11 and B22 can be arbitrarily adjusted.

[0045] Furthermore, the first reflecting mirror 241 can adjust the direction of beam B11 to form beam B12, the second reflecting mirror 242 can adjust the direction of beam B12 to form beam B13, the third reflecting mirror 243 can adjust the direction of beam B22 to form beam B23, and the fourth reflecting mirror 244 can adjust the direction of beam B23 to form beam B24.

[0046] In summary, by adjusting the positions of the first reflector 241, the second reflector 242, the third reflector 243, and the fourth reflector 244 in the horizontal plane and their rotation angles in the horizontal plane, beam B13 and beam B24 can intersect at a specific position in the horizontal plane, with an included angle of θ3.

[0047] In this embodiment, during the fabrication of a grating using a photopolymer, two interfering laser beams need to interfere at arbitrary angles in space, generating alternating bright and dark interference fringes. The difference in refractive index due to the brightness of these fringes in the photopolymer then forms a holographic grating. During this process, the angle between beams B13 and B24, and the normal vector of the photopolymer film, needs to be arbitrarily changed according to the design of the holographic grating. Furthermore, both laser beams need to be linearly polarized, and their power needs to be controlled. When using a mirror to change the beam direction, the polarization direction changes in space due to the change in the principal plane, causing the polarization directions of the two laser beams to become non-parallel, which in turn affects the accuracy of the interference fringes.

[0048] To solve the above problems, embodiments of this disclosure use a method such as Figure 2 The illustrated 9-DOF holographic grating fabrication optical path enables arbitrary distribution of two laser beams within a photopolymer film and achieves pre-defined interference fringes. This holographic grating fabrication optical path uses a first half-wave plate 231 and a second half-wave plate 233 to rotate the polarization direction of the laser beams by a specific angle, thereby adjusting the polarization direction of the two intersecting laser beams. Furthermore, this holographic grating fabrication optical path includes a mechanical adjustment frame, which is a five-axis polymer film clamp, allowing adjustment of the angle between the two intersecting laser beams so that they can enter the recording medium at any angle.

[0049] According to the holographic grating fabrication system provided in this disclosure, a laser beam is split into two beams by using a polarization beam splitter, and the polarization directions of the two beams are perpendicular to the horizontal plane and parallel to the rotation axis of the mirror group. The angle of the split laser beams is adjusted by the mirror group, and the optical path compensation component is used to adjust the optical path of the split laser beams, so that the two split laser beams can form interference fringes and be recorded in the recording medium to form a holographic grating. The optical path for fabricating this holographic grating has the advantages of being simple and easy to adjust.

[0050] like Figure 3 As shown, this disclosure provides a method for fabricating a holographic grating, which uses the holographic grating fabrication system described above to fabricate the holographic grating. The method includes:

[0051] Step S301: The laser beam is split into two beams using a polarization beam splitter and the intensity of the split laser beams is adjusted, as well as the polarization direction of the beams is adjusted so that the polarization directions of the two split laser beams are perpendicular to the horizontal plane and parallel to the rotation axis of the mirror. The laser beams are generated by a laser source.

[0052] Step S302: The laser beam split by the polarization beam splitter is mirror-reflected by a mirror group to form two intersecting laser beams with a set angle. The set angle is adjusted according to the rotation angle of the mirror group, wherein the mirror group includes the aforementioned mirrors.

[0053] Step S303: Using a recording medium, receive two intersecting laser beams that interfere with each other, and record the interference fringes of the two intersecting laser beams by varying the refractive index and / or transmittance as the two intersecting laser beams change, thus forming a holographic grating.

[0054] The technical solution of this disclosure provides a method for fabricating a holographic grating, which simplifies the optical path of the holographic grating fabrication and makes the holographic grating fabrication system simple and easy to adjust. This optical path can form two coherent beams with arbitrary angles at the recording medium, and the polarization direction is always perpendicular to the horizontal plane, thereby causing interference between the two intersecting laser beams. After adjusting the angle between the normal vector of the recording medium and the interference beams, a holographic grating with grating vectors of arbitrary direction and length can finally be formed in the recording medium.

[0055] In this embodiment of the disclosure, a beam adjustment component can be used to adjust the diameter of the laser beam so that the beam size of the two intersecting laser beams at the intersection is matched. The beam adjustment component includes a beam expander and an aperture, wherein the beam expander is disposed upstream of the optical path of the polarization beam splitter, and the aperture is disposed downstream of the optical path of the polarization beam splitter.

[0056] Specifically, adjusting the beam expander and the grating can change the spot size of two intersecting laser beams, so that the spot sizes of the two intersecting laser beams match at the intersection, thereby forming clearer interference fringes.

[0057] In this embodiment of the disclosure, the refractive index compensation component 250 can be used to change the refractive index of the recording medium boundary, so that two intersecting laser beams can enter the recording medium.

[0058] In this embodiment of the disclosure, an optical path compensation component can be used to adjust the optical path of two intersecting laser beams with a set angle, such that the optical path difference between the two intersecting laser beams is a first value, wherein the two intersecting laser beams with the optical path difference of the first value can interfere.

[0059] In this embodiment of the present disclosure, the polarization beam splitter includes a first polarization beam splitter and a second polarization beam splitter connected sequentially in the optical path of the laser beam. The first polarization beam splitter includes a half-wave plate and a polarization beam splitter prism, and the second polarization beam splitter includes a half-wave plate and a polarization beam splitter prism.

[0060] In this embodiment, the reflector assembly includes a first and a second reflector disposed downstream of the optical path of the first polarization beam splitter, and a third and a fourth reflector disposed downstream of the optical path of the second polarization beam splitter. Specifically, the first, second, third, and fourth reflectors are located in a horizontal plane and can move freely in a two-dimensional direction within the horizontal plane, and can rotate about an axis perpendicular to the horizontal plane. The first, second, third, and fourth reflectors can be used to form two beams of light that intersect at any position within the horizontal plane at any angle.

[0061] In this embodiment of the disclosure, the refractive index compensation component can be a liquid refractive index compensation medium with a specific refractive index or a prism with a specific shape that contacts the recording medium. A refractive index matching liquid is provided at the gap between the refractive index compensation component and the recording medium to eliminate the gap between the refractive index compensation component and the recording medium.

[0062] By setting a refractive index compensation component with a specific shape and refractive index, the influence of total internal reflection can be eliminated, allowing two intersecting laser beams to enter the recording medium at any angle.

[0063] In this embodiment, a mechanical adjustment frame can be used to adjust the three-dimensional position and three-axis rotation angle of the recording medium. Specifically, the mechanical adjustment frame can perform three-dimensional movement and three-axis rotation in space, thereby driving the recording medium to move and changing its three-dimensional position and the orientation of its material normal vector in space. Thus, a holographic grating with arbitrary spatial orientation and arbitrary grating period can be formed in the recording medium by interfering with two beams of coherent light at arbitrary angles.

[0064] Specifically, in this embodiment, spatially continuous grating recording can be formed, thereby creating holographic gratings of arbitrary size. During the recording of holographic gratings, after one holographic grating has been exposed and recorded, the position of the recording medium can be adjusted to record a second holographic grating. Thus, spatially spliced ​​and superimposed holographic gratings can be formed in the recording medium through splicing. Furthermore, the wavelength of the coherent light can be changed to form spliced ​​and superimposed multicolor holographic gratings in the recording medium. To optimize production efficiency, the recording medium can be prepared as a roll material or a sheet recording medium can be fixed on a conveyor belt. For example, the recording medium can be a polymer film in roll or sheet form. After one grating has been exposed and recorded, the next sheet of recording medium material is introduced through the roll or conveyor belt for holographic grating exposure and recording, achieving continuous production.

[0065] In addition, the recording medium can also be a holographic plate or a dichromate gel, and is not limited to these.

[0066] According to the holographic grating fabrication method provided in this disclosure, a laser beam is split into two beams by using a polarization beam splitter, and the polarization directions of the two beams are perpendicular to the horizontal plane and parallel to the rotation axis of the mirror group. The angle of the split laser beams is adjusted by the mirror group, and the optical path compensation component is used to adjust the optical path of the split laser beams, so that the two split laser beams can form interference fringes and be recorded in the recording medium to form a holographic grating. The optical path for fabricating this holographic grating has the advantages of being simple and easy to adjust.

[0067] The above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A holographic grating fabrication system, characterized in that, The holographic grating fabrication system includes: A laser source used to generate a laser beam; A polarization beam splitter is used to split a laser beam into two beams, adjust the intensity of the split laser beams, and adjust the polarization direction of the beams so that the polarization directions of the two split laser beams are perpendicular to the horizontal plane and parallel to the rotation axis of the mirror. The polarization beam splitter includes a first polarization beam splitter and a second polarization beam splitter connected sequentially in the optical path of the laser beam. The first polarization beam splitter and the second polarization beam splitter each include a half-wave plate and a polarization beam splitter prism. By adjusting the rotation angle of the half-wave plate in the first polarization beam splitter and the half-wave plate in the second polarization beam splitter, the polarization direction of the two split laser beams is adjusted to be perpendicular to the horizontal plane. A reflector assembly, including the reflectors, is used to reflect the split laser beam output by the polarization beam splitter to form two intersecting laser beams with a set angle. The set angle is adjusted according to the rotation angle of the reflector assembly. The reflector assembly includes a first and a second reflector disposed downstream of the optical path of the first polarization beam splitter, and a third and a fourth reflector disposed downstream of the optical path of the second polarization beam splitter. The first, second, third, and fourth reflectors are all located in the same horizontal plane and can move in two dimensions and rotate around an axis perpendicular to the horizontal plane. The first and second reflectors reflect one of the laser beams twice, and the third and fourth reflectors reflect the other laser beam twice, so that the two intersecting laser beams intersect at any position in the horizontal plane with any angle. An optical path compensation component is disposed on the optical path of a laser beam to adjust the optical path of two intersecting laser beams having a set angle, such that the optical path difference between the two intersecting laser beams is a first value, wherein the two intersecting laser beams with an optical path difference of the first value can interfere. A recording medium receives two intersecting laser beams that are interfering with each other, and records the interference fringes of the two intersecting laser beams by varying their refractive index and / or transmittance, thereby forming a holographic grating.

2. The holographic grating fabrication system according to claim 1, characterized in that, The holographic grating fabrication system further includes a spot adjustment component, comprising a beam expander and an aperture, respectively disposed upstream and downstream of the optical path of the polarization beam splitter, for adjusting the diameter of the laser beam so that the spot sizes of the two intersecting laser beams match at the intersection.

3. The holographic grating fabrication system according to claim 1, characterized in that, The holographic grating fabrication system also includes: A refractive index compensation component is disposed at the junction of the two intersecting laser beams to change the refractive index of the recording medium boundary, so that the two intersecting laser beams can enter the recording medium.

4. The holographic grating fabrication system according to claim 3, characterized in that, The optical path compensation component is connected between the second polarization beam splitter and the recording medium.

5. The holographic grating fabrication system according to claim 3, characterized in that, The refractive index compensation component includes a liquid refractive index compensation medium or a prism, and a refractive index matching liquid is disposed between the refractive index compensation component and the recording medium.

6. The holographic grating fabrication system according to claim 1, characterized in that, The holographic grating fabrication system further includes a mechanical adjustment frame, which is rotatably connected to the recording medium and used to adjust the three-dimensional position and three-axis rotation angle of the recording medium.

7. The holographic grating fabrication system according to claim 1, characterized in that, The recording medium includes any one of holographic plates, dichromate gels, and polymer films in roll or sheet form.

8. A method for fabricating a holographic grating, characterized in that, The method for fabricating a holographic grating using the holographic grating fabrication system according to any one of claims 1 to 7 includes: A laser beam is split into two beams using a polarization beam splitter, and the intensity and polarization direction of the split laser beams are adjusted so that the polarization directions of the two split laser beams are perpendicular to the horizontal plane and parallel to the rotation axis of the mirror. The laser beams are generated by a laser source. The laser beam split by the polarization beam splitter is mirror-reflected by a mirror group to form two intersecting laser beams with a set angle. The set angle is adjusted according to the rotation angle of the mirror group, wherein the mirror group includes the mirrors. The two intersecting laser beams are received using a recording medium, and the interference fringes of the two intersecting laser beams are recorded by varying the refractive index and / or transmittance of the two intersecting laser beams to form a holographic grating.

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