Polarizing beam splitter, optical device having same, spectroscopy method

Abstract

The invention discloses a polarization beam splitter, optical equipment with the polarization beam splitter, a beam splitting method and a manufacturing method, and relates to the technical field of optical devices. The polarization beam splitter comprises a protective layer; the diffraction grating layer is located on the protection layer, the diffraction grating layer comprises optical units which are arranged at equal intervals, each optical unit comprises at least two polarization modulation layers which are sequentially stacked in the incident beam transmission direction, and the grating period of the diffraction grating layer ranges from 570 nanometers to 590 nanometers. By the adoption of the polarization beam splitter, incident beams in different polarization states can be spatially separated in the transmission diffraction order through the hierarchical structure, the structure is simple, the complexity of an optical system is remarkably reduced, and efficient integration is facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of optical devices, and in particular to a polarization beam splitter and an optical device, a light splitting method, and a manufacturing method having the same. Background Art

[0002] As an important spectroscopic element, the polarization beam splitter can split the incident light beam into two orthogonal polarization directions: transverse electric polarization (TE) and transverse magnetic polarization (TM), and guide these outgoing light beams to propagate along different paths. It can be widely used in optical communications, quantum logic operations, sensors, precision measurements and other fields.

[0003] At present, the polarization beam splitters in the related technology mainly include polarization beam splitters based on birefringence effect, photonic crystal polarization beam splitters and optical waveguide polarization beam splitters, etc. However, the polarization beam splitters based on birefringence effect require sufficient thickness to separate the two polarized lights, which is not suitable for optical path integration. The photonic crystal polarization beam splitters and optical waveguide polarization beam splitters require additional coupling devices to guide the incident light beam, and the optical system structure is complex. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the related art, it is desired to provide a polarization beam splitter and an optical device, a splitting method, and a manufacturing method having the same, which have a simple structure and are easy to integrate.

[0005] In a first aspect, the present application provides a polarization beam splitter, the polarization beam splitter comprising:

[0006] Protective layer;

[0007] A diffraction grating layer is located on the protective layer, the diffraction grating layer includes optical units arranged at equal intervals, the optical units include at least two polarization modulation layers stacked in sequence along the transmission direction of the incident light beam, and the grating period Λ of the diffraction grating layer is 570 nanometers to 590 nanometers.

[0008] Optionally, in some embodiments of the present application, the two polarization modulation layers include a first polarization modulation layer and a second polarization modulation layer, and both the first polarization modulation layer and the second polarization modulation layer are columnar structures.

[0009] Optionally, in some embodiments of the present application, the column structure includes a cylinder, a prism or a frustum.

[0010] Optionally, in some embodiments of the present application, the polarization modulation layer located at the top of the two polarization modulation layers is a tantalum pentoxide layer, and the polarization modulation layer located at the bottom is a magnesium fluoride layer.

[0011] Optionally, in some embodiments of the present application, the duty ratio of the polarization modulation layer located at the top and the duty ratio of the polarization modulation layer located at the bottom are both 0.5 to 0.55.

[0012] Optionally, in some embodiments of the present application, the polarization modulation layer located at the top has a thickness of 900 nanometers to 1020 nanometers;

[0013] And / or, the polarization modulation layer at the bottom has a thickness of 150 nanometers to 420 nanometers.

[0014] Optionally, in some embodiments of the present application, the protective layer is silica glass or microcrystalline glass.

[0015] Optionally, in some embodiments of the present application, the thickness of the protective layer is greater than 10 microns.

[0016] Optionally, in some embodiments of the present application, the central wavelength λ of the incident light beam is 540 nanometers to 560 nanometers, and

[0017] In a second aspect, the present application provides an optical device, comprising the polarization beam splitter described in any one of the first aspects.

[0018] Optionally, in some embodiments of the present application, the optical device is a virtual reality display device, an augmented reality display device, or a mixed reality display device.

[0019] In a third aspect, the present application provides a spectroscopic method for a polarization beam splitter, the spectroscopic method being used for the polarization beam splitter described in any one of the first aspects, the spectroscopic method comprising:

[0020] Receiving an incident light beam irradiated on a surface of the optical unit, wherein the incident light beam includes transverse electrically polarized light and transverse magnetically polarized light;

[0021] The incident light beam is spatially separated in the transmission diffraction order by at least two polarization modulation layers in the optical unit to obtain the transverse electric polarized light and the transverse magnetic polarized light.

[0022] In a fourth aspect, the present application provides a method for manufacturing a polarization beam splitter, the manufacturing method being used to manufacture the polarization beam splitter described in any one of the first aspects, the manufacturing method comprising:

[0023] Provides a protective layer;

[0024] Vapor depositing at least two polarization modulation layers on the protective layer, and spin coating photoresist;

[0025] After the at least two polarization modulation layers subjected to spin coating are subjected to at least two holographic exposures with exposure directions mutually forming a preset angle, the polarization beam splitter is obtained through development and etching operations.

[0026] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0027] The embodiments of the present application provide a polarization beam splitter and an optical device, a splitting method, and a manufacturing method having the same. The incident light beam is spatially modulated by arranging a diffraction grating layer on a protective layer. The grating period is 570 nanometers to 590 nanometers, that is, the diffraction grating layer can interact with the incident light field, change the electromagnetic field transmission form of the incident light field on the surface of the diffraction grating layer, and realize polarization control. At the same time, at least two polarization modulation layers stacked in the diffraction grating layer can transmit the light beam, so that the hierarchical structure can be used to spatially separate the incident light beams of different polarization states in the transmission diffraction order. The structure is simple, the complexity of the optical system is significantly reduced, and efficient integration is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the three-dimensional structure of a polarization beam splitter provided in an embodiment of the present application;

[0029] Figure 2 A schematic diagram of a single-period three-dimensional structure of a polarization beam splitter provided in an embodiment of the present application;

[0030] Figure 3 A schematic diagram of a single-period three-dimensional structure of another polarization beam splitter provided in an embodiment of the present application;

[0031] Figure 4 A method provided in the embodiment of the present application Figure 2 A side view of the single-period stereostructure shown;

[0032] Figure 5 A diffraction efficiency diagram corresponding to a polarization beam splitter with different structural parameters provided in an embodiment of the present application;

[0033] Figure 6 A diffraction efficiency diagram corresponding to another polarization beam splitter with different structural parameters provided in an embodiment of the present application;

[0034] Figure 7 A structural block diagram of an optical device provided in an embodiment of the present application;

[0035] Figure 8 A schematic diagram of a light splitting method of a polarization beam splitter provided in an embodiment of the present application;

[0036] Fig. 9 An incident light beam provided in an embodiment of the present application is Figure 2Schematic diagram of diffraction results of the single-periodic stereo structure shown at normal incidence;

[0037] Fig.10 A method provided in the embodiment of the present application Figure 8 Bottom view of the diffraction result shown;

[0038] Fig.11 A schematic flow chart of a method for manufacturing a polarization beam splitter provided in an embodiment of the present application.

[0039] Reference numerals:

[0040] 1-polarization beam splitter, 11-protective layer, 12-diffraction grating layer, 121-optical unit, a1-first polarization modulation layer, a2-second polarization modulation layer, b1-polarization modulation layer at the top, b2-polarization modulation layer at the bottom, f-duty ratio, Λ-grating period, h1-thickness of the polarization modulation layer at the top, h2-thickness of the polarization modulation layer at the bottom, h3-thickness of the protective layer. DETAILED DESCRIPTION

[0041] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0042] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Figures 1 to 11 The polarization beam splitter provided in the embodiments of the present application and the optical device, the splitting method and the manufacturing method thereof are described in detail.

[0043] Please refer to Figure 1 , which is a schematic diagram of the three-dimensional structure of a polarization beam splitter provided by an embodiment of the present application. The polarization beam splitter 1 includes a protective layer 11 and a diffraction grating layer 12 located on the protective layer 11, the diffraction grating layer 12 includes optical units 121 arranged at equal intervals, wherein the optical unit 121 includes at least two polarization modulation layers stacked in sequence along the transmission direction of the incident light beam, that is, the number of polarization modulation layers includes but is not limited to two, three and four, and the grating period Λ of the diffraction grating layer 12 is 570 nanometers to 590 nanometers, that is, according to the grating equation, the grating period Λ determines the size parameters such as the spacing between adjacent optical units, thereby the diffraction grating layer 12 can interact with the incident light field to change the electromagnetic field transmission form of the incident light field on the surface of the diffraction grating layer 12, thereby realizing polarization control, and at the same time, the light beam can be transmitted through at least two polarization modulation layers to spatially separate the incident light beams of different polarization states in the transmission diffraction order, and the structure is simple.

[0044] In an example, see Figure 2The single-period three-dimensional structure schematic diagram of the polarization beam splitter shown in the figure, the at least two polarization modulation layers include but are not limited to the first polarization modulation layer a1 and the second polarization modulation layer a2, etc., and the first polarization modulation layer a1 and the second polarization modulation layer a2 can both be cylindrical structures. Further, the cylindrical structure includes a cylinder, a prism or a frustum, for example Figure 2 The first polarization modulation layer a1 and the second polarization modulation layer a2 shown in the figure can both be cylinders. In this case, the bottom areas of the upper and lower cylinders are the same. The advantage of such a configuration is that the structure is simple and the processing is convenient. For another example, the first polarization modulation layer a1 and the second polarization modulation layer a2 can both be prisms, and the prisms include but are not limited to triangular prisms, quadrangular prisms and pentagonal prisms. For another example, Figure 3 The first polarization modulation layer a1 and the second polarization modulation layer a2 shown can also be both frustums. In this case, the bottom area of ​​the upper frustum is equal to the top area of ​​the lower frustum. The advantage of this setting is that it can be flexibly selected according to actual usage requirements and is more diversified.

[0045] In another example, the polarization modulation layer b1 at the top of the at least two polarization modulation layers in the embodiment of the present application may be a tantalum pentoxide (Ta2O5) layer, and the polarization modulation layer b2 at the bottom may be a magnesium fluoride (MgF2) layer, thereby utilizing the high refractive index and low dispersion characteristics of tantalum pentoxide to modulate the effective refractive index of the grating, and comprehensively utilizing the good polarization characteristics of magnesium fluoride to enhance the light transmittance of the diffraction grating layer 12 and improve the diffraction efficiency. Figure 2 As shown in the figure, the polarization modulation layer b1 at the top may correspond to the first polarization modulation layer a1, and the polarization modulation layer b2 at the bottom may correspond to the second polarization modulation layer a2, that is, the first polarization modulation layer a1 is a tantalum pentoxide layer, and the second polarization modulation layer a2 is a magnesium fluoride layer. The polarization modulation layer b1 at the top and the polarization modulation layer b2 at the bottom may both be columnar structures, please refer to the above description for details, which will not be repeated here.

[0046] Furthermore, for example Figure 4 As shown, in the embodiment of the present application, the duty ratios of the polarization modulation layer b1 at the top and the polarization modulation layer b2 at the bottom are both 0.5 to 0.55, where f represents the duty ratio. The advantage of this setting is that the photoresist width can be controlled by adjusting the exposure dose and exposure time during the processing and manufacturing process with the same duty ratio, and the preparation can be completed by one exposure, development and etching, which greatly improves the production efficiency. At the same time, the duty ratio range with a central value can also give the production process a larger tolerance space.

[0047] Still see Figure 4In some embodiments of the present application, the thickness h1 of the polarization modulation layer b1 located at the top can be 900 nanometers to 1020 nanometers, and the thickness h2 of the polarization modulation layer b2 located at the bottom can be 150 nanometers to 420 nanometers; for example, in some other embodiments of the present application, the thickness h1 of the polarization modulation layer b1 located at the top can be 900 nanometers to 1020 nanometers; for example, in some other embodiments of the present application, the thickness h2 of the polarization modulation layer b2 located at the bottom can be 150 nanometers to 420 nanometers.

[0048] The protective layer 11 is introduced below. In the embodiment of the present application, the protective layer 11 can be exemplarily made of silica glass or microcrystalline glass, which can have excellent optical properties such as high temperature resistance, small thermal expansion coefficient and high transmittance, and help improve the stability and diffraction efficiency of the diffraction grating layer 12. Furthermore, the thickness h3 of the protective layer 11 can be greater than 10 microns, thereby ensuring the structural strength of the diffraction grating layer 12.

[0049] In other embodiments of the present application, the central wavelength λ of the incident light beam in all the above embodiments may be 540 nanometers to 560 nanometers, and The incident angle is normal incidence from the diffraction grating layer 12, which is beneficial to the integration of optical systems. The central wavelength λ covers the common working wavelength of green lasers, and high-efficiency diffraction can be achieved within the working wavelength range of 20 nanometers, ensuring wavelength compatibility. Specifically, during the diffraction phenomenon of the incident light beam passing through the diffraction grating layer 12, different diffraction orders can be divided according to the central wavelength λ, the grating period Λ and the incident angle. Since the two-dimensional grating is an extension of the one-dimensional grating, the diffraction equation of the two-dimensional grating is expressed as follows, that is,

[0050] sinθ m,n cosφ m,n = sinθcosφ+mλ / Λ x (1)

[0051] sinθ m,n sinφ m,n = sinθsinφ+nλ / Λ y (2)

[0052] In equations (1) and (2), φ represents the azimuth angle of the incident light beam, and θ represents the polar angle of the incident light beam; m,n represents the azimuth angle of the diffracted light at the (m,n) order, θ m,n represents the polar angle corresponding to the diffracted light at the (m,n) order; Λ x represents the period of the diffraction grating layer in the x direction, Λ y Indicates the period of the diffraction grating layer in the y direction. In order to facilitate processing and meet the symmetry of the grating structure, Λ x =Λy ; λ represents the central wavelength.

[0053] When satisfied When , the transmitted diffraction order is only (1,0), (-1,0), (0,1), (0,-1) and (0,0). The fewer the diffraction orders, the higher the energy utilization rate, which is more conducive to using phase to control the diffraction efficiency distribution. By selecting the material of the polarization modulation layer and changing the structural parameters of the diffraction grating layer, the phase of the incident light field in the diffraction grating layer can be changed, and the flow state of the electromagnetic field on the surface of the diffraction grating layer also changes accordingly, thereby controlling the distribution of the electric field vector and the magnetic field vector to achieve light modulation. For example Figure 5 and Figure 6 The following are the diffraction efficiency diagrams corresponding to polarization beam splitters with different structural parameters: Figure 5 The polarization beam splitter grating period Λ=577nm, the central wavelength λ=550nm, the protective layer thickness h3=50μm, the duty ratio f=0.52, and Figure 6 The polarization beam splitter grating period Λ = 580 nanometers, the central wavelength λ = 560 nanometers, the protective layer thickness h3 = 50 microns, and the duty ratio f = 0.535. It can be seen from the figure that when the transverse magnetic polarized light (TM) is incident from the diffraction grating layer 12 under normal incidence conditions, the diffraction efficiency η of the (0,-1) order and (0,1) order transmission diffraction orders are both greater than 35%, and when the transverse electric polarized light (TE) is incident from the diffraction grating layer 12 under normal incidence conditions, the diffraction efficiency η of the (1,0) order and (-1,0) order transmission diffraction orders are also greater than 35%. In addition, the test results show that when the incident light beam with a central wavelength λ of 550 nanometers is incident normally from the diffraction grating layer 12, the transmission diffraction energy of TM is mainly concentrated in the (0,-1) and (0,1) transmission diffraction orders, and the energy of each order can reach 40.16%, while the transmission diffraction energy of TE is mainly concentrated in the (1,0) and (-1,0) transmission diffraction orders, and the energy of each order can reach 40.16%, and the diffraction efficiency utilization rate is as high as 80%, realizing the spatial orthogonal decomposition of the polarization state of light.

[0054] The polarization beam splitter provided in the embodiment of the present application performs spatial modulation on the incident light beam by arranging a diffraction grating layer on the protective layer, and the grating period is 570 nanometers to 590 nanometers, that is, the diffraction grating layer can interact with the incident light field, change the electromagnetic field transmission form of the incident light field on the surface of the diffraction grating layer, and realize polarization control. At the same time, at least two polarization modulation layers stacked in the diffraction grating layer can transmit the light beam, so that the hierarchical structure can be used to spatially separate the incident light beams of different polarization states in the transmission diffraction order. The structure is simple, the complexity of the optical system is significantly reduced, and efficient integration is convenient.

[0055] Based on the above embodiments, the present application provides an optical device. Figure 7 , which is a structural block diagram of an optical device provided in an embodiment of the present application, the optical device 2 may include Figures 1 to 6 Corresponding to the polarization beam splitter 1 in any embodiment. In addition, the optical device 2 may further include a filter (not shown in the figure) so as to filter out stray light and obtain an incident light beam with a central wavelength λ of 540 nanometers to 560 nanometers.

[0056] Furthermore, in the embodiment of the present application, the optical device 2 may be a virtual reality (VR) display device, an augmented reality (AR) display device, or a mixed reality (MR) display device.

[0057] It should be noted that, for the description of the same contents in this embodiment as those in other embodiments, reference can be made to the description in other embodiments and will not be repeated here.

[0058] In the optical device provided in the embodiment of the present application, the polarization beam splitter spatially modulates the incident light beam by arranging a diffraction grating layer on the protective layer, and the grating period is 570 nanometers to 590 nanometers, that is, the diffraction grating layer can interact with the incident light field, change the electromagnetic field transmission form of the incident light field on the surface of the diffraction grating layer, and realize polarization control. At the same time, at least two polarization modulation layers stacked in the diffraction grating layer can transmit the light beam, so that the hierarchical structure can be used to spatially separate the incident light beams with different polarization states in the transmission diffraction order. The structure is simple, which significantly reduces the complexity of the optical system and facilitates efficient integration.

[0059] Based on the above embodiments, the present application provides a method for splitting light using a polarization beam splitter. Figure 8 , which is a schematic flow chart of a spectroscopic method of a polarization beam splitter provided in an embodiment of the present application. The spectroscopic method can be used for Figures 1 to 6 Corresponding to the polarization beam splitter 1 in any embodiment, the light splitting method specifically includes the following steps:

[0060] S101, receiving an incident light beam irradiated on a surface of an optical unit, where the incident light beam includes transverse electric polarized light and transverse magnetic polarized light.

[0061] S102, spatially separating the incident light beam in the transmission diffraction order through at least two polarization modulation layers in the optical unit to obtain transverse electric polarized light and transverse magnetic polarized light.

[0062] For example, Fig. 9 and Fig.10 As shown, the incident beam containing TE and TM (i.e. Fig. 9The TE / TM incident light in the optical fiber can be spatially separated in the transmission diffraction order after passing through the polarization beam splitter 1, and the energy of TM is mainly concentrated in the (0,-1) order and (0,1) order transmission diffraction orders, and the energy of TE is mainly concentrated in the (1,0) order and (-1,0) order transmission diffraction orders, thus realizing high-efficiency transmission-type orthogonal polarization decomposition and optical beam splitting functions.

[0063] It should be noted that, for the description of the same contents in this embodiment as those in other embodiments, reference can be made to the description in other embodiments and will not be repeated here.

[0064] The polarization beam splitter spectroscopic method provided in the embodiment of the present application spatially modulates the incident light beam through a diffraction grating layer provided on a protective layer of the polarization beam splitter, and the grating period is 570 nanometers to 590 nanometers, that is, the diffraction grating layer can interact with the incident light field, change the electromagnetic field transmission form of the incident light field on the surface of the diffraction grating layer, and realize polarization control. At the same time, at least two polarization modulation layers stacked in the diffraction grating layer can transmit the light beam, so that the hierarchical structure can be used to spatially separate the incident light beams of different polarization states in the transmission diffraction order. The structure is simple, the complexity of the optical system is significantly reduced, and efficient integration is convenient.

[0065] Based on the above embodiments, the present application provides a method for manufacturing a polarization beam splitter. Fig.11 , which is a schematic flow chart of a method for manufacturing a polarization beam splitter provided in an embodiment of the present application. The manufacturing method can be used to manufacture the polarization beam splitter 1 in any of the aforementioned embodiments. The manufacturing method specifically includes the following steps:

[0066] S201, providing a protective layer.

[0067] For example, in the embodiment of the present application, the protective layer 11 may be made of silica glass or glass-ceramics, which can have excellent optical properties such as high temperature resistance, small thermal expansion coefficient, and high transmittance, which helps to improve the stability and diffraction efficiency of the subsequently prepared diffraction grating layer 12. Furthermore, the thickness h3 of the protective layer 11 may be greater than 10 microns, thereby ensuring the structural strength of the diffraction grating layer 12.

[0068] S202, vapor depositing at least two polarization modulation layers on the protective layer, and spin coating photoresist.

[0069] For example, the vapor deposition method in the embodiments of the present application includes but is not limited to physical vapor deposition (PVD) and chemical vapor deposition (CVD).

[0070] The above-mentioned at least two polarization modulation layers may include a polarization modulation layer b1 located at the top and a polarization modulation layer b2 located at the bottom. Exemplarily, the deposition thickness of the polarization modulation layer b1 located at the top may be 900 nanometers to 1020 nanometers, and the deposition thickness of the polarization modulation layer b2 located at the bottom may be 150 nanometers to 420 nanometers.

[0071] S203, performing at least two holographic exposures with exposure directions forming a preset angle with each other on at least two polarization modulation layers subjected to spin coating at least twice, and then obtaining a polarization beam splitter through development and etching operations.

[0072] Exemplarily, if at least two polarization modulation layers include a polarization modulation layer b1 located at the top and a polarization modulation layer b2 located at the bottom, the two exposure directions may be at a preset angle of 90 degrees to each other. The advantage of such a setting is that the grating structure morphology of the two polarization modulation layers is simple, which saves process procedures, has a large manufacturing tolerance, and ensures product yield.

[0073] It should be noted that, for the description of the same contents in this embodiment as those in other embodiments, reference can be made to the description in other embodiments and will not be repeated here.

[0074] The polarization beam splitter manufacturing method provided in the embodiment of the present application, the polarization beam splitter manufactured by the manufacturing method spatially modulates the incident light beam by setting a diffraction grating layer on the protective layer, and the grating period is 570 nanometers to 590 nanometers, that is, the diffraction grating layer can interact with the incident light field, change the electromagnetic field transmission form of the incident light field on the surface of the diffraction grating layer, and realize polarization control. At the same time, at least two polarization modulation layers stacked in the diffraction grating layer can transmit the light beam, so that the hierarchical structure can be used to spatially separate the incident light beams with different polarization states in the transmission diffraction order. The structure is simple, the complexity of the optical system is significantly reduced, and it is convenient for efficient integration.

[0075] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0076] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A polarization beam splitter, characterized in that: The polarization beam splitter (1) comprises: A protective layer (11); A diffraction grating layer (12) located on the protective layer (11), the diffraction grating layer (12) comprising optical units (121) arranged at equal intervals, the optical units (121) comprising at least two polarization modulation layers stacked in sequence along a transmission direction of an incident light beam, and a grating period Λ of the diffraction grating layer (12) being 570 nanometers to 590 nanometers.

2. The polarization beam splitter according to claim 1, characterized in that: The at least two polarization modulation layers include a first polarization modulation layer (a1) and a second polarization modulation layer (a2), and the first polarization modulation layer (a1) and the second polarization modulation layer (a2) are both column structures.

3. The polarization beam splitter according to claim 2, characterized in that: The column structure includes a cylinder, a prism or a frustum.

4. The polarization beam splitter according to claim 1, characterized in that: The polarization modulation layer (b1) located at the top of the at least two polarization modulation layers is a tantalum pentoxide layer, and the polarization modulation layer (b2) located at the bottom is a magnesium fluoride layer.

5. The polarization beam splitter according to claim 4, characterized in that: The width ratio of the polarization modulation layer (b1) located at the top and the width ratio of the polarization modulation layer (b2) located at the bottom are both 0.5 to 0.

55.

6. The polarization beam splitter according to claim 4, characterized in that: The polarization modulation layer (b1) located at the top has a thickness of 900 nanometers to 1020 nanometers; And / or, the polarization modulation layer (b2) located at the bottom has a thickness of 150 nanometers to 420 nanometers.

7. The polarization beam splitter according to any one of claims 1 to 6, characterized in that: The protective layer (11) is silicon dioxide glass or microcrystalline glass.

8. The polarization beam splitter according to claim 7, characterized in that: The thickness of the protective layer (11) is greater than 10 micrometers.

9. The polarization beam splitter according to any one of claims 1 to 6, characterized in that: The central wavelength λ of the incident light beam is 540 nanometers to 560 nanometers, and 10. An optical device, characterized in that: The optical device (2) comprises the polarization beam splitter (1) according to any one of claims 1 to 9.

11. The optical device according to claim 10, characterized in that The optical device (2) is a virtual reality display device, an augmented reality display device or a mixed reality display device.

12. A method for splitting light using a polarization beam splitter, characterized in that: The spectroscopic method is used for the polarization beam splitter (1) according to any one of claims 1 to 9, and the spectroscopic method comprises: Receiving an incident light beam irradiated on a surface of an optical unit (121), wherein the incident light beam includes transverse electrically polarized light and transverse magnetically polarized light; The incident light beam is spatially separated at the transmission diffraction order by at least two polarization modulation layers in the optical unit (121) to obtain the transverse electric polarized light and the transverse magnetic polarized light.

13. A method for manufacturing a polarization beam splitter, characterized in that: The manufacturing method is used to manufacture the polarization beam splitter (1) according to any one of claims 1 to 9, and the manufacturing method comprises: Providing a protective layer (11); Vapor-depositing at least two polarization modulation layers on the protective layer (11), and spin-coating photoresist; After at least two polarization modulation layers that have been subjected to spin coating are subjected to at least two holographic exposures with exposure directions mutually forming a preset angle, the polarization beam splitter (1) is obtained through development and etching operations.

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