Ultraviolet laser double-incidence-angle long-wave pass filter
Patent Information
- Application Number
- CN202522215841.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-20
- Publication Date
- 2026-09-18
- Estimated Expiration
- 2035-10-20
AI Technical Summary
传统分光器件多基于正入射设计，在45°斜入射时因光程变化导致分光波长偏移、反射/透射效率下降，难以满足实际集成需求
[0025] This application discloses a long-pass filter for ultraviolet lasers with dual incident angles, which can achieve high reflection at 266nm short wavelength and high transmission at 355nm long wavelength under dual incident conditions of 0° and 45°, and at the same time has high reliability and long-term stability.
Smart Images
Figure CN224773224U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical thin film devices, and in particular to a long-wavelength filter with dual incident angles for ultraviolet lasers. Background Technology
[0002] In ultraviolet laser systems, it is often necessary to separate short-wavelength (266nm) and long-wavelength (355nm) lasers. For example, 266nm is used for high-precision micromachining, while 355nm is used for rough machining or inspection. Traditional beam splitters are mostly based on normal incidence designs. When incident at a 45° angle, the change in optical path causes a shift in the beam splitting wavelength and a decrease in reflection / transmission efficiency, making it difficult to meet practical integration requirements. Moreover, in the ultraviolet band (especially 266nm), high material absorption and film stress mismatch lead to a sharp deterioration in performance when incident at an angle, such as a decrease in emission efficiency at 266nm and 355nm. Summary of the Invention
[0003] In view of this, this application provides a long-pass filter for ultraviolet laser with dual incident angles, which can achieve high reflection of 266nm short wavelength and high transmission of 355nm long wavelength under incident conditions of 0° and 45°.
[0004] To achieve the above objectives, this application employs the following technical solution:
[0005] A long-wavelength ultraviolet laser dual-incident-angle filter, characterized in that it comprises a substrate, a filter film, and an antireflection film, wherein the filter film and the antireflection film are respectively disposed on two sides of the substrate; the filter film is a 21-layer film system consisting of alternating high-refractive-index HFO2 film layers and low-refractive-index SiO2 film layers; the 21-layer film system, from the substrate outwards, consists of:
[0006] The first layer is an HFO2 film with a thickness of 16.92 nm; the second layer is an SiO2 film with a thickness of 44.21 nm.
[0007] The third layer is an HFO2 film with a thickness of 35.31 nm; the fourth layer is an SiO2 film with a thickness of 48.23 nm.
[0008] The fifth layer is an HFO2 film with a thickness of 30.88 nm; the sixth layer is an SiO2 film with a thickness of 48.52 nm.
[0009] The 7th layer is an HFO2 film with a thickness of 31.28 nm; the 8th layer is an SiO2 film with a thickness of 51.83 nm.
[0010] The 9th layer is an HFO2 film with a thickness of 32.61 nm; the 10th layer is an SiO2 film with a thickness of 47.50 nm.
[0011] The 11th layer is an HFO2 film with a thickness of 31.97 nm; the 12th layer is an SiO2 film with a thickness of 47.84 nm.
[0012] The 13th layer is an HFO2 film with a thickness of 33.10 nm; the 14th layer is an SiO2 film with a thickness of 52.23 nm.
[0013] The 15th layer is an HFO2 film with a thickness of 30.35 nm; the 16th layer is an SiO2 film with a thickness of 48.03 nm.
[0014] The 17th layer is an HFO2 film with a thickness of 29.93 nm; the 18th layer is an SiO2 film with a thickness of 51.64 nm.
[0015] The 19th layer is an HFO2 film with a thickness of 37.52 nm; the 20th layer is an SiO2 film with a thickness of 59.23 nm.
[0016] The 21st layer is an HFO2 film with a thickness of 10.08 nm.
[0017] The present application discloses a long-pass ultraviolet laser filter with dual incident angles. The filter film employs a 21-layer film system, and the physical thickness of the high / low refractive index layers is adjusted to ensure high reflectivity for 266nm short-wavelength lasers and high transmittance for 355nm long-wavelength lasers under both normal and oblique incident conditions. Specifically, the reflectivity of 266nm short-wavelength lasers is ≥99.5%, and the transmittance of 355nm long-wavelength lasers is ≥99.5%. This solves the problems of low splitting efficiency and incompatibility of traditional filters when used with different incident angles.
[0018] In some embodiments, the antireflective film is a four-layer film system, wherein the four layers are arranged sequentially from the substrate outwards as follows:
[0019] The first layer is an HFO2 film with a thickness of 76.54 nm; the second layer is an SiO2 film with a thickness of 88.25 nm.
[0020] The third layer is an HFO2 film with a thickness of 61.07 nm; the fourth layer is an SiO2 film with a thickness of 45.81 nm.
[0021] In some embodiments, the substrate is fused silica or UV-grade CaF₂. 2， The surface roughness of the substrate is <1 nm.
[0022] In some embodiments, the HFO2 film has a refractive index of 2.20 for a short-wavelength laser at 266 nm and a refractive index of 2.05 for a long-wavelength laser at 355 nm; the SiO2 film has a refractive index of 1.48 for a short-wavelength laser at 266 nm and a refractive index of 1.47 for a long-wavelength laser at 355 nm.
[0023] In some embodiments, the filter has a reflectivity of ≥99.5% for 266nm short-wavelength laser and a transmittance of ≥99.5% for 355nm long-wavelength laser when incident at 0° and 45°.
[0024] As can be seen from the above technical solution, this application has at least the following advantages and positive effects:
[0025] This application discloses a long-pass filter for ultraviolet lasers with dual incident angles, which can achieve high reflection at 266nm short wavelength and high transmission at 355nm long wavelength under dual incident conditions of 0° and 45°, and at the same time has high reliability and long-term stability. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the structure of an embodiment of this application;
[0027] Figure 2 This is an optical path diagram of an embodiment of this application;
[0028] Figure 3 This is a spectral diagram of the filter film in the embodiments of this application;
[0029] Figure 4 This is a spectral diagram of the antireflection membrane in the embodiments of this application.
[0030] Labeling explanation: 1. Filter film; 2. Substrate; 3. Anti-reflection film. Detailed Implementation
[0031] To make the objectives, technical solutions, and advantages of this application clearer, the application will be described in further detail below with reference to the accompanying drawings. The terminology used in the embodiments section of this application is only for explaining specific embodiments and is not intended to limit the application.
[0032] See Figures 1 to 4 This application provides a long-wavelength ultraviolet laser dual-incident-angle filter, comprising a substrate 2, a filter film 1, and an antireflection film 3, wherein the filter film 1 and the antireflection film 3 are respectively disposed on two sides of the substrate 2; the filter film 1 is a 21-layer film system consisting of alternating high-refractive-index HFO2 film layers and low-refractive-index SiO2 film layers; the 21-layer film system, from the substrate 2 outwards, consists of:
[0033] The first layer is an HFO2 film with a thickness of 16.92 nm; the second layer is an SiO2 film with a thickness of 44.21 nm.
[0034] The third layer is an HFO2 film with a thickness of 35.31 nm; the fourth layer is an SiO2 film with a thickness of 48.23 nm.
[0035] The fifth layer is an HFO2 film with a thickness of 30.88 nm; the sixth layer is an SiO2 film with a thickness of 48.52 nm.
[0036] The 7th layer is an HFO2 film with a thickness of 31.28 nm; the 8th layer is an SiO2 film with a thickness of 51.83 nm.
[0037] The 9th layer is an HFO2 film with a thickness of 32.61 nm; the 10th layer is an SiO2 film with a thickness of 47.50 nm.
[0038] The 11th layer is an HFO2 film with a thickness of 31.97 nm; the 12th layer is an SiO2 film with a thickness of 47.84 nm.
[0039] The 13th layer is an HFO2 film with a thickness of 33.10 nm; the 14th layer is an SiO2 film with a thickness of 52.23 nm.
[0040] The 15th layer is an HFO2 film with a thickness of 30.35 nm; the 16th layer is an SiO2 film with a thickness of 48.03 nm.
[0041] The 17th layer is an HFO2 film with a thickness of 29.93 nm; the 18th layer is an SiO2 film with a thickness of 51.64 nm.
[0042] The 19th layer is an HFO2 film with a thickness of 37.52 nm; the 20th layer is an SiO2 film with a thickness of 59.23 nm.
[0043] The 21st layer is an HFO2 film with a thickness of 10.08 nm.
[0044] This ultraviolet laser dual-incident-angle long-pass filter employs a 21-layer filter system, with adjusted physical thicknesses of high / low refractive index layers to ensure high reflectivity for 266nm short-wavelength lasers and high transmittance for 355nm long-wavelength lasers under both normal and oblique incidence conditions. Specifically, the reflectivity of 266nm short-wavelength lasers is ≥99.5%, and the transmittance of 355nm long-wavelength lasers is ≥99.5%. This design solves the problems of low splitting efficiency and incompatibility of traditional filters when used with different incidence angles.
[0045] The antireflective film 3 is a four-layer film system, and the four layers are arranged sequentially from the substrate 2 outwards as follows:
[0046] The first layer is an HFO2 film with a thickness of 76.54 nm; the second layer is an SiO2 film with a thickness of 88.25 nm.
[0047] The third layer is an HFO2 film with a thickness of 61.07 nm; the fourth layer is an SiO2 film with a thickness of 45.81 nm.
[0048] The substrate 2 is fused silica, with a transmittance of >85% at 266nm / 355nm when incident at 45°, or ultraviolet-grade CaF2, wherein the surface roughness of the substrate is <1nm to ensure film adhesion.
[0049] The HFO2 film has a refractive index of 2.20 for a short wavelength laser at 266 nm and a refractive index of 2.05 for a long wavelength laser at 355 nm; the SiO2 film has a refractive index of 1.48 for a short wavelength laser at 266 nm and a refractive index of 1.47 for a long wavelength laser at 355 nm.
[0050] The filter has a reflectivity of ≥99.5% for 266nm short-wavelength laser and a transmittance of ≥99.5% for 355nm long-wavelength laser when incident at 0° and 45°.
[0051] See Figure 3 The optical performance parameters of the filter film shown in the spectrum are as follows: the thick line represents 45° incident light, with visible R 99.7% @ 266nm and T 99.7% @ 355nm; the thin line represents 0° incident light, with visible R 99.7% @ 266nm and T 99.9% @ 355nm.
[0052] See Figure 4 The optical performance indicators of the antireflection film in this embodiment are as follows, as shown in the spectrum: the thick line represents 45° incident light with a visible R of 0.4% at 355nm; the thin line represents 0° incident light with a visible R of 0.3% at 355nm.
[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of this application, and are not intended to limit them; although the embodiments of this application have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. An ultraviolet laser dual incidence angle long wave pass filter, characterized by: The system includes a substrate (2), a filter film (1), and an antireflection film (3), wherein the filter film (1) and the antireflection film (3) are respectively disposed on two sides of the substrate (2); the filter film (1) is a 21-layer film system consisting of alternating high-refractive-index HFO2 film layer and low-refractive-index SiO2 film layer; the 21-layer film system consists of the following layers from the substrate (2) outwards: The first layer is an HFO2 film with a thickness of 16.92 nm; the second layer is an SiO2 film with a thickness of 44.21 nm. The third layer is an HFO2 film with a thickness of 35.31 nm; the fourth layer is an SiO2 film with a thickness of 48.23 nm. The fifth layer is an HFO2 film with a thickness of 30.88 nm; the sixth layer is an SiO2 film with a thickness of 48.52 nm. The 7th layer is an HFO2 film with a thickness of 31.28 nm; the 8th layer is an SiO2 film with a thickness of 51.83 nm. The 9th layer is an HFO2 film with a thickness of 32.61 nm; the 10th layer is an SiO2 film with a thickness of 47.50 nm. The 11th layer is an HFO2 film with a thickness of 31.97 nm; the 12th layer is an SiO2 film with a thickness of 47.84 nm. The 13th layer is an HFO2 film with a thickness of 33.10 nm; the 14th layer is an SiO2 film with a thickness of 52.23 nm. The 15th layer is an HFO2 film with a thickness of 30.35 nm; the 16th layer is an SiO2 film with a thickness of 48.03 nm. The 17th layer is an HFO2 film with a thickness of 29.93 nm; the 18th layer is an SiO2 film with a thickness of 51.64 nm. The 19th layer is an HFO2 film with a thickness of 37.52 nm; the 20th layer is an SiO2 film with a thickness of 59.23 nm. The 21st layer is an HFO2 film with a thickness of 10.08 nm.
2. The ultraviolet laser dual incidence angle long-wave pass filter according to claim 1, characterized in that: The antireflective film (3) is a four-layer film system, and the four layers are arranged sequentially from the substrate (2) outwards as follows: The first layer is an HFO2 film with a thickness of 76.54 nm; the second layer is an SiO2 film with a thickness of 88.25 nm. The third layer is an HFO2 film with a thickness of 61.07 nm; the fourth layer is an SiO2 film with a thickness of 45.81 nm.
3. The ultraviolet laser dual incidence angle long-wave pass filter according to claim 1, characterized in that: The substrate (2) is fused silica or UV grade CaF 2， The surface roughness of the substrate (2) is < 1 nm.
4. The ultraviolet laser dual incidence angle long-wave pass filter according to claim 1, wherein: The HFO2 film has a refractive index of 2.20 for a short wavelength laser at 266 nm and a refractive index of 2.05 for a long wavelength laser at 355 nm; the SiO2 film has a refractive index of 1.48 for a short wavelength laser at 266 nm and a refractive index of 1.47 for a long wavelength laser at 355 nm.
5. The ultraviolet laser dual incidence angle long-wave pass filter according to claim 1, wherein: The filter has a reflectivity of ≥99.5% for 266nm short-wavelength laser and a transmittance of ≥99.5% for 355nm long-wavelength laser when incident at 0° and 45°.