High-gradient depolarization long-wave-pass optical filter
By employing a specific arrangement of TA2O5 and SiO2 films in optical filters, the problem of low steepness in long-pass filters under oblique incidence is solved, enabling diversified selection of light sources and simplification of optical path design in optical systems.
Patent Information
- Application Number
- CN202520537019.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2035-03-26
AI Technical Summary
In existing technologies, when light is incident at an oblique angle, the steepness of long-pass filters is not high, and the transition range from the reflection region to the transmission region is wide, resulting in polarization separation between P-polarized light and S-polarized light. This limits the selection of light sources in the optical system and increases the complexity and design difficulty of the optical path system.
A specific arrangement of TA2O5 and SiO2 film layers, including lower, middle and upper stack structures, is used to form a high-steep depolarization long-pass optical filter through coating. This ensures that the polarization separation region between P-polarized light and S-polarized light is narrowed when incident obliquely, achieving a steep transition between high reflection and high transmission bands.
It effectively narrows the transition range from the reflection region to the transmission region, improves the separation of polarized light, enriches the selection of light sources in the optical system, and reduces the design complexity of the optical path system.
Smart Images
Figure CN223926651U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to optical vacuum coating technology, and particularly to optical long-pass filters, especially the research and application of depolarizing filter coating. Specifically, it relates to a high-steep depolarizing long-pass optical filter. Background Technology
[0002] Optical systems, due to design requirements, often need to achieve high reflection in the short-wavelength band and high transmission in the longer-wavelength band. For example, light from 370-410 nm needs high reflection, while light from 420-450 nm needs high transmission. This transition from high reflection to high transmission requires a filter with a spatial dimension of only 10 nm. When the light incident at an angle of 0 degrees (perpendicular incidence) on the filter lens, achieving this requirement is relatively easy in design and development. It can be achieved using a conventional (0.5HL0.5H)^15 film stack structure. H: high refractive index coating material such as TA2O5, L: low refractive index coating material SiO2, and the spectral curve is shown below. Figure 1 As shown.
[0003] When the incident angle is not equal to 0 degrees (non-perpendicular incident), polarization separation occurs, and the optical behavior of S-polarized light and P-polarized light is completely different. With oblique incident light, the reflection cutoff band of a long-pass filter shifts to shorter wavelengths, and the slope becomes less steep. The transition region from the high-reflection band to the high-transmission band widens, making it impossible to achieve the splitting characteristic of one wavelength being highly reflective and the other highly transmittant for two relatively similar wavelengths. Taking the most commonly used oblique incident angle of 45 degrees as an example, the resulting spectral curve is as follows... Figure 2 As shown: the thin line is the spectral curve of 0-degree perpendicular incidence. Since there is no polarization separation at 0-degree incidence, the P-polarized light and S-polarized light coincide with the thin line.
[0004] When incident at an oblique angle, the high reflection band can only be in the short wavelength region before 400 nm, and the high transmission band can only be in the long wavelength region after 430 nm. There is a 30 nm transition region from high reflection to high transmission, and there is a 10 nm polarization separation region between P-polarized light and S-polarized light.
[0005] The current setup limits the selection of light sources in the optical system, preventing the selection of relatively adjacent light sources as signal sources, thus increasing the complexity and design difficulty of the optical path system.
[0006] Therefore, it is necessary to provide a high-steep depolarization long-pass optical filter to solve the above problems. Utility Model Content
[0007] The purpose of this invention is to provide a high-steepness depolarizing long-wavelength optical filter.
[0008] This utility model achieves the above objectives through the following technical solution:
[0009] A high-steepness depolarization long-pass optical filter includes a TA2O5 film layer and a SiO2 film layer, wherein there are several TA2O5 film layers and several SiO2 film layers arranged in a certain manner.
[0010] The bottom stack structure consists of a TA2O5 film layer, a SiO2 film layer, a TA2O5 film layer, and a 0.8SiO2 film layer arranged in sequence.
[0011] Several intermediate stack structures: 0.8SiO2 film layer, TA2O5 film layer, SiO2 film layer, TA2O5 film layer, SiO2 film layer, TA2O5 film layer, SiO2 film layer, TA2O5 film layer, SiO2 film layer, TA2O5 film layer, 0.8SiO2 film layer are arranged in sequence;
[0012] The upper stack structure consists of a 0.8SiO2 film layer and a TA2O5 film layer arranged sequentially.
[0013] Furthermore, the number of intermediate stack structures is six.
[0014] Furthermore, TA2O5 films are used as high-refractive-index films, while SiO2 films are used as low-refractive-index films.
[0015] Furthermore, both the TA2O5 film and the SiO2 film were obtained through a coating process.
[0016] Furthermore, the thicknesses of the TA2O5 film, SiO2 film, TA2O5 film, and 0.8SiO2 film in the lower stack structure are 45nm, 150.55nm, 78.48nm, and 70.64nm, respectively.
[0017] Furthermore, the thicknesses of the 0.8SiO2 film, TA2O5 film, SiO2 film, TA2O5 film, SiO2 film, TA2O5 film, SiO2 film, TA2O5 film, and 0.8SiO2 film in the intermediate stack structure are, respectively, 70.64nm, 44.94nm, 109.55nm, 92.4nm, 94.89nm, 56.58nm, 380.77nm, 216.5nm, and 101.7nm.
[0018] Furthermore, the thicknesses of the 0.8SiO2 film and the TA2O5 film in the upper stack structure are 117.43 nm and 78.41 nm, respectively.
[0019] Furthermore, during the coating process, the substrate is heated to 260°C, and the evaporation flow rate is 300-450 mA for TA2O5 and 70-100 mA for SiO2.
[0020] Furthermore, during the coating process, the rotation speed is 30 r / min, and the vacuum level is 2.0 x 10^(-2) Pa for TA2O5 and 9 x 10^(-3) Pa for SiO2.
[0021] Compared with existing technologies, this invention effectively solves the problems of low steepness of long-pass filters and wide transition range between reflection and transmission regions when incident at an oblique angle; it improves the polarization separation of P-polarized and S-polarized light, thus achieving the depolarization effect of light incident at an oblique angle; it perfectly solves the problem that optical systems can only select light sources with relatively large wavelength intervals, and cannot select relatively adjacent light sources as signal sources, thus enriching the design options in optical path systems and reducing the complexity of optical path system design. Attached Figure Description
[0022] Figure 1 This is a spectral diagram of a conventional membrane stack structure.
[0023] Figure 2 The spectral curve is obtained using a conventional membrane stack structure with an oblique incident angle of 45 degrees as an example.
[0024] Figure 3 This is a schematic diagram of the present invention.
[0025] Figure 4 This is a spectral curve obtained using a 45-degree oblique incident angle as an example. Detailed Implementation
[0026] Example:
[0027] See Figure 1 The purpose of this embodiment is to provide a high-steepness depolarized long-wavelength optical filter.
[0028] This utility model achieves the above objectives through the following technical solution:
[0029] A high-steep depolarization long-pass optical filter includes a TA2O5 film and a SiO2 film. The TA2O5 film is used as a high refractive index film and is marked as H, and the SiO2 film is used as a low refractive index film and is marked as L.
[0030] The number of TA2O5 film layers H and SiO2 film layers L are both numerous, and these numerous TA2O5 film layers H and SiO2 film layers L are arranged in an array to form:
[0031] Lower stack structure 100: TA2O5 film layer, SiO2 film layer, TA2O5 film layer, and 0.8SiO2 film layer are arranged in sequence;
[0032] Several intermediate stack structures 200: 0.8SiO2 film layer, TA2O5 film layer, SiO2 film layer, TA2O5 film layer, SiO2 film layer, TA2O5 film layer, SiO2 film layer, TA2O5 film layer, and 0.8SiO2 film layer are arranged in sequence;
[0033] The upper stack structure 300 consists of a 0.8SiO2 film layer and a TA2O5 film layer arranged sequentially.
[0034] There are six 200-cell intermediate stack structures.
[0035] Both the TA2O5 film H and the SiO2 film L were obtained by coating.
[0036] The thicknesses of the TA2O5 film, SiO2 film, TA2O5 film, and 0.8SiO2 film in the lower stack structure 100 are 45nm, 150.55nm, 78.48nm, and 70.64nm, respectively.
[0037] The thicknesses of the 0.8SiO2 film, TA2O5 film, SiO2 film, TA2O5 film, SiO2 film, TA2O5 film, SiO2 film, TA2O5 film, and 0.8SiO2 film in the medium-reactor structure 200 are, respectively: 70.64nm, 44.94nm, 109.55nm, 92.4nm, 94.89nm, 56.58nm, 380.77nm, 216.5nm, and 101.7nm.
[0038] The thicknesses of the 0.8SiO2 film and the TA2O5 film in the upper stack structure 300 are 117.43 nm and 78.41 nm, respectively.
[0039] During coating, the substrate is heated to 260°C, and the evaporation flow rate is 300-450mA for TA2O5 and 70-100mA for SiO2.
[0040] During coating, the rotation speed is 30 r / min, and the vacuum degree is 2.0 x 10^(-2) Pa for TA2O5 and 9 x 10^(-3) Pa for SiO2.
[0041] Using the most commonly used oblique incidence angle of 45 degrees as the oblique incidence condition, the spectral curve of this embodiment is shown in the figure. Figure 4 The spectral curves show that the original 30 nm transition region, the 390-410 nm high-reflectivity region, and the 420-450 nm high-transmittance region have been narrowed to 10 nm. The 10 nm polarization separation region between P-polarized and S-polarized light has been improved and shortened to 3 nm. This perfectly solves the problem in optical systems where light sources can only be selected with relatively large wavelength intervals, rather than adjacent light sources, thus enriching the design options and reducing the design complexity of optical path systems.
[0042] Compared with existing technologies, this invention effectively solves the problems of low steepness of long-pass filters and wide transition range between reflection and transmission regions when incident at an oblique angle; it improves the polarization separation of P-polarized and S-polarized light, thus achieving the depolarization effect of light incident at an oblique angle; it perfectly solves the problem that optical systems can only select light sources with relatively large wavelength intervals, and cannot select relatively adjacent light sources as signal sources, thus enriching the design options in optical path systems and reducing the complexity of optical path system design.
[0043] The above descriptions are merely some embodiments of this utility model. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of this utility model, and all such modifications and improvements fall within the protection scope of this utility model.
Claims
1. A high- steepness depolarizing long-wave pass optical filter, characterized in that: The film layers include TA2O5 film layers and SiO2 film layers, the number of the TA2O5 film layers and the SiO2 film layers is several, and the several TA2O5 film layers and the SiO2 film layers are arranged to form: The lower stack structure: TA2O5 film layer, SiO2 film layer, TA2O5 film layer, 0.8 SiO2 film layer are arranged in sequence; The several middle stack structures: 0.8 SiO2 film layer, TA2O5 film layer, SiO2 film layer, TA2O5 film layer, SiO2 film layer, TA2O5 film layer, SiO2 film layer, TA2O5 film layer, 0.8 SiO2 film layer are arranged in sequence; The upper stack structure: 0.8 SiO2 film layer, TA2O5 film layer are arranged in sequence.
2. A high-ledge depolarizing long-wave pass optical filter according to claim 1, characterized in that: The number of the middle stack structures is six.
3. A high-ledge depolarizing long-wave pass optical filter according to claim 2, characterized in that: The TA2O5 film layer is used as a high refractive index film layer, and the SiO2 film layer is used as a low refractive index film layer.
4. A high-ledge depolarizing long-wave pass optical filter according to claim 3, characterized in that: The TA2O5 film layer and the SiO2 film layer are obtained by coating.
5. A high-ledge depolarizing long-wave pass optical filter according to claim 4, wherein: The thicknesses of the TA2O5 film layer, the SiO2 film layer, the TA2O5 film layer and the 0.8 SiO2 film layer of the lower stack structure are 45nm, 150.55nm, 78.48nm and 70.64nm respectively.
6. A high-ledge depolarizing long-wave pass optical filter according to claim 5, wherein: The thicknesses of the 0.8 SiO2 film layer, the TA2O5 film layer, the SiO2 film layer, the TA2O5 film layer, the SiO2 film layer, the TA2O5 film layer, the SiO2 film layer, the TA2O5 film layer and the 0.8 SiO2 film layer of the middle stack structure are 70.64nm, 44.94nm, 109.55nm, 92.4nm, 94.89nm, 56.58nm, 380.77nm, 216.5nm and 101.7nm respectively.
7. A high-ledge depolarizing long-wave pass optical filter according to claim 6, characterized in that: The thicknesses of the 0.8 SiO2 film layer and the TA2O5 film layer of the upper stack structure are 117.43nm and 78.41nm respectively.
8. A high-ledge depolarizing long-wave pass optical filter according to claim 7, characterized in that: When coating, the substrate is heated to 260°, and the evaporation flow rate is 300-450mA for TA2O5 and 70-100mA for SiO2.
9. A high-ledge depolarizing long-wave pass optical filter according to claim 8, characterized in that: When coating, the rotating speed is 30r / min, and the vacuum degree is 2.0x10^(-2) Pa for TA2O5 and 9x10^(-3) Pa for SiO2.