Polarization-maintaining film, laser total reflection polarization-maintaining prism and method for realizing total reflection polarization-maintaining

Abstract

The present invention relates to a polarization-maintaining film for a total reflection prism, which is formed by sequentially stacking the following film layers from the inner layer close to the total reflection surface of the total reflection prism to the outer layer: a first SiO2 film layer with a thickness of 37.2 - 93.9 nm, a first TiO2 film layer with a thickness of 123.0 - 223.9 nm, a second SiO2 film layer with a thickness of 44.3 - 189.6 nm, a second TiO2 film layer with a thickness of 43.0 - 54.8 nm, and a third SiO2 film layer with a thickness of 98.7 - 142.6 nm. The inventive solution uses the total reflection principle of the total reflection prism to eliminate reflection loss and achieve an effect of 100% reflectivity; the inventive solution uses the total reflection principle of the total reflection prism to eliminate polarization-related loss of the reflected light, so that the reflectivities of P-polarized light and S-polarized light are equal.

Description

Technical Field

[0001] The present invention relates to the field of optics, and particularly to a polarization-maintaining film, a total reflection polarization-maintaining prism, and a method for realizing total reflection polarization-maintaining. Background Art

[0002] The mirror in an optical system will change the polarization state of the incident light to a certain extent, that is, residual polarization is generated, which will reduce the imaging ability of the optical system. Therefore, in some optical reflection systems, residual polarization should be avoided or reduced so that the polarization state of the incident light remains unchanged after reflection, that is, a polarization-maintaining mirror is required. Polarization-maintaining reflection is equivalent to that the beam does not undergo phase delay after passing through the mirror, and the intensities of P-polarized light and S-polarized light remain the same.

[0003] Generally, optical reflection displacement devices, such as corner cube prisms, right-angle prisms, etc., all realize the beam turning-back based on the total reflection principle of the beam from an optically denser medium to an optically thinner medium. Due to the influence of total reflection on the phase loss of the beam, the polarization state of the reflected beam changes compared with the incident beam, making it inapplicable to application scenarios with polarization-maintaining characteristics requirements. Summary of the Invention

[0004] The present invention provides a polarization-maintaining film, a total reflection polarization-maintaining prism, and a method for realizing total reflection polarization-maintaining. The polarization-maintaining film can be plated or adhered to the total reflection surface of the total reflection prism to form a total reflection polarization-maintaining prism. When light is reflected through the total reflection polarization-maintaining prism and the method for realizing total reflection polarization-maintaining of the present invention, as long as the incident angle of the light on the total reflection surface of the total reflection prism through the total reflection prism is greater than the total reflection angle, the phase difference of the reflected light is 180°, and the intensities of P-polarized light and S-polarized light remain the same.

[0005] Solution 1)

[0006] A polarization-maintaining film for a total reflection prism is successively stacked from the inner layer close to the total reflection surface of the total reflection prism to the outer layer by the following film layers:

[0007] A first SiO film layer with a thickness of 37.2 - 93.9 nm 2 A first TiO film layer with a thickness of 123.0 - 223.9 nm 2 A second SiO film layer with a thickness of 44.3 - 189.6 nm 2 A second TiO film layer with a thickness of 43.0 - 54.8 nm 2 A third SiO film layer with a thickness of 98.7 - 142.6 nm 2 film layer.

[0008] Specifically, the thickness of the first SiO 2 film layer is 48.6 nm; the first TiO 2The film thickness is 137.9 nm; the second SiO 2 The film thickness is 44.3 nm; the second TiO 2 The film thickness is 43.0 nm; the third SiO 2 The film thickness is 142.6 nm.

[0009] Specifically, the first SiO 2 The film thickness is 37.2 nm; the first TiO 2 The film thickness is 123.0 nm; the second SiO 2 The film thickness is 46.5 nm; the second TiO 2 The film thickness is 54.8 nm; the third SiO 2 The film thickness is 107.6 nm.

[0010] Specifically, the first SiO 2 The film thickness is 93.9 nm; the first TiO 2 The film thickness is 223.9 nm; the second SiO 2 The film thickness is 189.6 nm; the second TiO 2 The film thickness is 43.7 nm; the third SiO 2 The film thickness is 98.7 nm.

[0011] Scheme II)

[0012] A total reflection polarization maintaining prism, which includes a right-angled triangular prism. The prism surface of the right-angled triangular prism consists of an inclined surface and a first right-angled surface and a second right-angled surface that are respectively connected to both sides of the inclined surface and are perpendicularly connected to each other. One of the right-angled surfaces is the light incident surface of the right-angled triangular prism, and the inclined surface is the total reflection surface of the right-angled triangular prism; the other right-angled surface is the light exit surface of the right-angled triangular prism; a polarization maintaining film as described in Scheme I is provided outside the inclined surface of the right-angled triangular prism.

[0013] Antireflection film layers are provided on both right-angled surfaces of the right-angled triangular prism.

[0014] The right-angled triangular prism is an isosceles right-angled prism.

[0015] The material used for the right-angled triangular prism is a glass material that can transmit light energy.

[0016] The material used for the right-angled triangular prism is K9 glass with a refractive index n = 1.52.

[0017] A method for achieving total reflection polarization maintaining is provided. On the surface of a total reflection prism used as a total reflection surface, a polarization maintaining film as described in Solution (1) is provided, and light is incident on the total reflection surface of the total reflection prism through the total reflection prism at an incident angle greater than the total reflection angle of the total reflection prism.

[0018] The total reflection prism is a right-angled triangular prism, and the material of the right-angled triangular prism is K9 glass with a refractive index n = 1.52. Light is incident on the total reflection surface of the total reflection prism through the total reflection prism at an incident angle of 45 degrees.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) The inventive solution uses the total reflection principle of the total reflection prism to eliminate reflection loss and achieve an effect of 100% reflectivity;

[0021] (2) The inventive solution uses the total reflection principle of the total reflection prism to eliminate polarization-related loss of reflected light, so that the reflectivities of P-polarized light and S-polarized light are equal;

[0022] (3) The inventive solution uses a polarization maintaining film to solve the problem of reflection phase loss, eliminates the influence of reflection on the polarization state of the light beam, and achieves the effect of reflection polarization maintaining;

[0023] (4) The polarization maintaining film of the inventive solution can achieve a phase difference of 180 degrees after reflection, that is, it can adjust the circular polarization rotation direction while maintaining polarization. For example, when the reflection phase difference is 180 degrees, the right-handed circularly polarized light becomes left-handed circularly polarized light after reflection;

[0024] (5) The polarization maintaining film of the inventive solution can be plated on one surface of the prism to achieve light beam deflection, or can be plated on two surfaces of the prism to achieve light beam turning back;

[0025] (6) The inventive solution is insensitive to small-angle position errors or processing dimension errors of the prism. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of the geometric structure and optical path of the present invention.

[0027] Figure 2 It is a reflectivity characteristic diagram of the present invention (Example 1).

[0028] Figure 3 It is a diagram of the phase change characteristic of the reflected light of the present invention in Example 1.

[0029] Figure 4 It is a diagram of the phase change characteristic of the reflected light of the present invention in Example 2.

[0030] Figure 5It is the diagram of the phase change characteristics of the reflected light in Embodiment 3 of the present invention. Detailed implementation manners

[0031] The following is a detailed description of the content of the present invention in conjunction with the accompanying drawings of the specification and specific embodiments:

[0032] Embodiment 1:

[0033] A polarization-maintaining film for a total reflection prism is formed by sequentially stacking the following film layers from the inner layer close to the total reflection surface of the total reflection prism to the outer layer:

[0034] Specifically, the thickness of the first SiO 2 film layer is 48.6 nm; the thickness of the first TiO 2 film layer is 137.9 nm; the thickness of the second SiO 2 film layer is 44.3 nm; the thickness of the second TiO 2 film layer is 43.0 nm; the thickness of the third SiO 2 film layer is 142.6 nm.

[0035] A total reflection polarization-maintaining prism includes a right-angled triangular prism. The prism surface of the right-angled triangular prism is composed of an inclined surface and a first right-angled surface and a second right-angled surface that are respectively connected to both sides of the inclined surface and are perpendicularly connected to each other. One of the right-angled surfaces is the light incident surface of the right-angled triangular prism, the inclined surface is the total reflection surface of the right-angled triangular prism, and the other right-angled surface is the light exit surface of the right-angled triangular prism; the polarization-maintaining film is provided on the outer side of the inclined surface of the right-angled triangular prism.

[0036] Anti-reflection film layers are provided on both right-angled surfaces of the right-angled triangular prism.

[0037] The right-angled triangular prism is an isosceles right-angled prism.

[0038] The material used for the right-angled triangular prism is a glass material through which light energy can pass.

[0039] The material used for the right-angled triangular prism is K9 glass with a refractive index n = 1.52.

[0040] In this embodiment, the refractive index of the SiO 2 film layer is 1.46, and the refractive index of the TiO 2 film layer is 2.4.

[0041] A method for realizing total reflection and polarization maintenance is to provide the polarization-maintaining film as described in Scheme (1) on the surface of the total reflection prism used as the total reflection surface, and make light enter the total reflection surface of the total reflection prism through the total reflection prism at an incident angle greater than the total reflection angle of the total reflection prism;

[0042] The polarization-maintaining film described above is formed by successively stacking the following film layers from the inner layer to the outer layer of the total reflection surface of the total reflection prism:

[0043] The total reflection prism described above is a right-angled triangular prism, and the material used for the right-angled triangular prism is K9 glass with a refractive index n = 1.52, so that light is incident on the total reflection surface of the total reflection prism at an incident angle of 45 degrees.

[0044] This embodiment adopts the polarization-maintaining reflection of circularly polarized laser with a wavelength of 633 nm:

[0045] The prism glass material in this embodiment is K9 (n = 1.52), and the total reflection angle of its glass material with respect to air is 42 degrees. As Figure 1 shown, the reflection angle of the optical path shown is 45 degrees, meeting the total reflection condition.

[0046] As Figure 2 shown, it is the reflectivity characteristic diagram of the present invention. It can be seen from the figure that the total reflection surface of the total reflection polarization-maintaining prism provided by the present invention can totally reflect 100% of the P polarization state and the S polarization state of the 633 nm circularly polarized laser, that is, Rs = Rp = 100% @ 633 nm.

[0047] As Figure 3 shown, it is the phase change characteristic diagram of the reflected light of the present invention. It can be seen from the figure that the phase difference between the two polarization states of the laser after a single total reflection is 180 degrees, and the rotation directions of the circularly polarized lights are opposite. That is, assuming that the 633 nm laser is a right-handed circularly polarized light, it becomes a left-handed circularly polarized light after being reflected by the prism of the present invention; vice versa.

[0048] Embodiment 2

[0049] The thickness of the first SiO 2 film layer in this embodiment is 37.2 nm; the thickness of the first TiO 2 film layer is 123.0 nm; the thickness of the second SiO 2 film layer is 46.5 nm; the thickness of the second TiO 2 film layer is 54.8 nm; the thickness of the third SiO 2 film layer is 107.6 nm. Different from the above embodiment, this embodiment uses a 405 nm laser. As Figure 2 shown, it is the reflectivity characteristic diagram of the present invention. It can be seen from the figure that the total reflection surface of the total reflection polarization-maintaining prism provided by the present invention can totally reflect 100% of the P polarization state and the S polarization state of the 405 nm circularly polarized laser, that is, Rs = Rp = 100% @ 405 nm.

[0050] As Figure 4As shown, it is the characteristic diagram of the phase change of the reflected light of the present invention. It can be seen from the figure that the phase difference between the two polarization states of the laser after a single total reflection is 180 degrees, and the rotation directions of the circularly polarized light are opposite. That is, assuming that the 405 nm laser is right-handed circularly polarized light, it becomes left-handed circularly polarized light after being reflected by the prism of the present invention; and vice versa.

[0051] Example 3

[0052] The thickness of the first SiO 2 film layer is 93.9 nm; the thickness of the first TiO 2 film layer is 223.9 nm; the thickness of the second SiO 2 film layer is 189.6 nm; the thickness of the second TiO 2 film layer is 43.7 nm; the thickness of the third SiO 2 film layer is 98.7 nm. For the 1064 nm laser

[0053] Figure 2 As shown, it is the reflectivity characteristic diagram of the present invention. It can be seen from the figure that the total reflection surface of the total reflection polarization-preserving prism provided by the present invention can totally reflect 100% of the P polarization state and the S polarization state of the 1064 nm circularly polarized laser, that is, Rs = Rp = 100% @ 1064 nm.

[0054] As Figure 5 shown, it is the characteristic diagram of the phase change of the reflected light of the present invention. It can be seen from the figure that the phase difference between the two polarization states of the laser after a single total reflection is 180 degrees, and the rotation directions of the circularly polarized light are opposite. That is, assuming that the 1064 nm laser is right-handed circularly polarized light, it becomes left-handed circularly polarized light after being reflected by the prism of the present invention; and vice versa.

[0055] In summary, the phase difference between the two polarization states of the laser after a single total reflection is 180 degrees, the polarization state of the laser remains unchanged as circularly polarized light, but the rotation directions of the circularly polarized light are opposite.

[0056] The above specific embodiments only explain the technical solutions of the present invention in detail. The present invention is not only limited to the above embodiments. Any improvement or replacement based on the principle of the present invention shall be within the protection scope of the present invention.

Claims

1. A polarization-maintaining film for a total reflection prism, characterized in that: it is composed of the following film layers stacked in sequence from the inner layer close to the total reflection surface of the total reflection prism to the outer layer: The first SiO film layer with a thickness of 37.2 - 93.9 nm 2 The first TiO film layer with a thickness of 123.0 - 223.9 nm 2 The second SiO film layer with a thickness of 44.3 - 189.6 nm 2 The second TiO film layer with a thickness of 43.0 - 54.8 nm 2 The third SiO film layer with a thickness of 98.7 - 142.6 nm 2 film layer.

2. The polarization-maintaining film according to claim 1, characterized in that: The first SiO 2 film layer has a thickness of 48.6 nm; the first TiO 2 film layer has a thickness of 137.9 nm; the second SiO 2 film layer has a thickness of 44.3 nm; the second TiO 2 film layer has a thickness of 43.0 nm; the third SiO 2 film layer has a thickness of 142.6 nm.

3. The polarization-maintaining film according to claim 1, characterized in that: The first SiO 2 film layer has a thickness of 37.2 nm; the first TiO 2 film layer has a thickness of 123.0 nm; the second SiO 2 film layer has a thickness of 46.5 nm; the second TiO 2 film layer has a thickness of 54.8 nm; the third SiO 2 film layer has a thickness of 107.6 nm.

4. The polarization-maintaining film according to claim 1, characterized in that: The first SiO 2 film layer has a thickness of 93.9 nm; the first TiO 2 film layer has a thickness of 223.9 nm; the second SiO 2 film layer has a thickness of 189.6 nm; the second TiO 2 film layer has a thickness of 43.7 nm; the third SiO 2 film layer has a thickness of 98.7 nm.

5. A total reflection polarization-maintaining prism, characterized in that: the total reflection polarization-maintaining prism includes a right-angled triangular prism, and the prism surface of the right-angled triangular prism is composed of an inclined surface (1) and a first right-angled surface (2) and a second right-angled surface (3) that are respectively connected to both sides of the inclined surface (1) and are perpendicularly connected to each other. One of the right-angled surfaces is the light incident surface of the right-angled triangular prism, the inclined surface (1) is the total reflection surface of the right-angled triangular prism, and the other right-angled surface is the light exit surface of the right-angled triangular prism; a polarization-maintaining film (4) described in any one of claims 1-4 is provided on the outer side of the inclined surface (1) of the right-angled triangular prism.

6. A total reflection polarization-maintaining prism according to claim 5, characterized in that: antireflection film layers are provided on both right-angled surfaces of the right-angled triangular prism; the right-angled triangular prism is an isosceles right-angled prism.

7. A total reflection polarization-maintaining prism according to claim 5, characterized in that: the material used for the right-angled triangular prism is a glass material that can transmit light energy.

8. A total reflection polarization-maintaining prism according to claim 7, characterized in that: the material used for the right-angled triangular prism is K9 glass with a refractive index n = 1.

52.

9. A method for realizing total reflection and polarization maintenance, characterized in that: a polarization-maintaining film described in any one of claims 1-4 is provided on the surface of the total reflection prism used as the total reflection surface, and light is incident on the total reflection surface of the total reflection prism through the total reflection prism at an incident angle greater than the total reflection angle of the total reflection prism.

10. The method for realizing total reflection and polarization maintenance according to claim 9, characterized in that: the total reflection prism is a right-angled triangular prism, the material used for the right-angled triangular prism is K9 glass with a refractive index n = 1.52, and light is incident on the total reflection surface of the total reflection prism through the total reflection prism at an incident angle of 45 degrees.

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