Laser reflector film layer preparation process

Abstract

The invention relates to the technical field of laser reflector film layer preparation, in particular to a laser reflector film layer preparation process which comprises the following steps: providing an optical substrate, and cleaning and polishing the surface of the substrate by using ultrasonic waves; designing a multi-layer film structure, wherein the multi-layer film structure is formed by alternating a high-refractive-index material and a low-refractive-index material; sequentially depositing a high-refractive-index material and a low-refractive-index material on the surface of the substrate by adopting a physical vapor deposition or chemical vapor deposition technology to form a multilayer film structure; in the deposition process, the thickness and optical performance of the film layer are monitored in real time through an optical monitoring system; carrying out annealing treatment on the deposited film layer; depositing a protective layer on the surface of the film layer. By reducing the cost of the film material and adopting the matching ratio of 1: 2, the dependence on the high-refractive-index film material is reduced, meanwhile, the requirement for the low-refractive-index film material is increased, the processing time is shortened, the stress of the film layer is effectively reduced, the tensile stress and the pressure stress are counteracted, and the film layer is prevented from being broken.

Description

Technical Field

[0001] The present invention relates to the technical field of laser mirror film layer preparation, and specifically to a laser mirror film layer preparation process. Background Art

[0002] As a key optical component in a laser system, a laser mirror is widely used in fields such as industrial processing, medical equipment, scientific research experiments, and national defense technology. With the rapid development of laser technology, the output power of lasers has been continuously increasing, and the performance requirements for laser mirrors have become increasingly stringent. Especially in high-power laser applications, a laser mirror not only needs to have an ultra-high reflectivity (usually required to have a reflectivity ≥ 99.9% at a wavelength of 1064 nm or 532 nm), but also needs to meet the strict requirements of anti-laser damage and an ultra-low surface profile change rate.

[0003] In a laser system, the reflectivity of a mirror directly affects the energy utilization efficiency and system performance of the laser. For lasers with wavelengths of 1064 nm (near-infrared) and 532 nm (green light), the mirror needs to achieve an ultra-high reflectivity (≥ 99.9%) within a specific wavelength range to minimize light energy loss. Due to film layer design or material limitations, traditional mirrors often have difficulty meeting the requirements of both high reflectivity and a wide wavelength band, so it is necessary to optimize the film layer structure and material selection to achieve this goal. High-power lasers (such as kilowatt-level or higher power) generate extremely high energy densities during operation, which poses a severe challenge to the anti-laser damage ability of the mirror. Laser damage mainly manifests as film layer ablation, cracks, or detachment, and in severe cases, it can lead to the failure of the mirror. To improve the anti-laser damage ability, the mirror film layer needs to have the following characteristics: low absorption rate, high thermal stability, and high mechanical strength. In high-power laser applications, the surface profile change of the mirror directly affects the quality and pointing stability of the laser beam. Due to the high laser energy density, the mirror is prone to thermal deformation during long-term operation or high-power irradiation, resulting in surface profile changes (such as curvature changes or local deformations). This kind of surface profile change will introduce wavefront aberration and reduce the performance of the laser system. Therefore, the mirror needs to have an ultra-low surface profile change rate, usually requiring that under high-power laser irradiation, the surface profile change is less than λ / 10 (λ is the laser wavelength).

[0004] Currently, the common laser mirrors on the market still have the following limitations in meeting ultra-high reflectivity, anti-laser damage, and ultra-low surface profile change rate:

[0005] Film layer material limitations: Traditional high refractive index materials (such as TiO 2 , Ta 2 O 5 ) can achieve high reflectivity, but their thermal stability and anti-laser damage ability are limited.

[0006] Stress problem: During the deposition process of the multi-layer film structure, internal stress is likely to be generated, resulting in film layer peeling or surface shape change.

[0007] High cost: The preparation process of high-performance mirrors is complex and the material cost is high, making it difficult to meet the needs of large-scale applications.

[0008] For the related technical problems, no solutions have been proposed. Summary of the Invention

[0009] In view of the problems in the related art, the present invention provides a preparation process for the film layer of a laser mirror to overcome the above-mentioned technical problems existing in the existing related art. The purpose of the present invention is to reduce the film material cost, adopt a matching ratio of 1:2, reduce the dependence on high-refractive-index film materials, and at the same time increase the demand for low-refractive-index film materials, which can significantly reduce the film material cost by about 30% and reduce the processing time. This process effectively reduces the film layer stress, enables the tensile stress and compressive stress to cancel each other out, thereby allowing the film layer thickness to increase while the surface shape change remains within a small range, avoiding the rupture of the film layer.

[0010] To achieve the above object, the present invention provides the following technical solution: A preparation process for the film layer of a laser mirror, comprising the following steps:

[0011] Step 1: Provide an optical substrate, clean the surface of the substrate using ultrasonic waves to remove contaminants on the surface of the substrate, and then polish the substrate to ensure that the surface roughness is less than 1 nm to reduce scattering loss;

[0012] Step 2: Design a multi-layer film structure according to the laser wavelength and reflectivity requirements. The multi-layer film structure is composed of high-refractive-index materials and low-refractive-index materials alternately, and the thickness of each layer of film is 1 / 4 of the laser wavelength;

[0013] Step 3: Adopt physical vapor deposition or chemical vapor deposition technology to sequentially deposit high-refractive-index materials and low-refractive-index materials on the surface of the substrate to form a multi-layer film structure; The specific multi-layer film structure is:

[0014] Sub / 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S 88.54H261.73S 88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S88.54H 261.73S 88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H261.73S 88.54H 261.73S 88.54H261.73S 88.54H / Air, where H and S represent high refractive index material and low refractive index material respectively;

[0015] Step Four: During the deposition process, the film thickness and optical properties are monitored in real time through an optical monitoring system to ensure the uniformity and compactness of the film;

[0016] Step Five: Anneal the deposited film to eliminate the internal stress of the film and improve the stability and adhesion of the film;

[0017] Step Six: Deposit a protective layer on the film surface to improve the mechanical strength and environmental stability of the film.

[0018] Preferably, in Step One, the optical substrate is quartz, and the thermal expansion coefficient of the substrate is less than 5x10 -6 / K.

[0019] Preferably, in Step Two, the high refractive index material is hafnium dioxide, and the refractive index range is 2.0 - 2.5.

[0020] Preferably, in Step Two, the low refractive index material is silicon dioxide, and the refractive index is 1.45 - 1.48.

[0021] Preferably, in Step Three, the physical vapor deposition technique is one of electron beam evaporation or magnetron sputtering; the electron beam evaporation is to heat and evaporate the high refractive index material and low refractive index material by an electron beam and deposit them on the substrate surface; the magnetron sputtering is to bombard the target material with ions to sputter and deposit the high refractive index material and low refractive index material on the substrate surface.

[0022] Preferably, in Step Three, the chemical vapor deposition technique is one of plasma enhanced chemical vapor deposition or atomic layer deposition, and during the deposition process, the stress distribution of the film is further optimized by adjusting the flow rate and pressure of the reaction gas.

[0023] Preferably, in step five, the annealing treatment is carried out at a temperature of 200°C to 500°C for 1 to 4 hours to eliminate the internal stress in the film layer and improve the film layer adhesion.

[0024] Preferably, in step six, the protective layer is one of silicon dioxide or silicon nitride, with a thickness of 10 to 100 nm, and the deposition process parameters of the protective layer are the same as those of the low-refractive-index material to further reduce the process complexity and cost.

[0025] Preferably, in step two, the reflectivity of the multi-layer film is greater than 99.9%, and the film layer stress is less than 100 MPa.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] (1) The present invention is a preparation process for the film layer of a laser mirror. By optimizing the film material cost and adopting a reflectivity matching ratio of 1:2, compared with the traditional 1:1 design, this reduces the dependence on high-refractive-index film materials, while increasing the demand for low-refractive-index film materials, effectively reducing the film material cost by about 30%, considering that the price of high-refractive-index film materials is approximately 150 times that of low-refractive-index film materials;

[0028] (2) The present invention is a preparation process for the film layer of a laser mirror, which reduces the processing time. For the same thickness, because the evaporation rate of the low-refractive-index film is about 3 times that of the high-refractive-index film material.

[0029] (3) The present invention is a preparation process for the film layer of a laser mirror. This matching effectively reduces the film layer stress, cancels the tensile stress and compressive stress, enables the film layer to be thick enough, with little change in the surface shape, and the film layer will not crack. Description of the Drawings

[0030] Figure 1 It is a flowchart of the process of the present invention. Detailed Embodiments

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0032] Embodiment 1

[0033] Please refer to Figure 1 As shown, the present invention proposes a technical solution for a preparation process of a film layer of a laser mirror: a preparation process of a film layer of a laser mirror, including the following steps:

[0034] Step one: Provide an optical substrate, clean the surface of the substrate using ultrasonic waves to remove contaminants on the surface of the substrate, and then polish the substrate to ensure that the surface roughness is less than 1 nm to reduce scattering loss;

[0035] Step 2: Design a multilayer film structure according to the requirements of laser wavelength and reflectivity. The multilayer film structure is composed of high-refractive-index materials and low-refractive-index materials alternatingly, and the thickness of each layer of film is 1 / 4 of the laser wavelength;

[0036] Step 3: Adopt physical vapor deposition or chemical vapor deposition technology to sequentially deposit high-refractive-index materials and low-refractive-index materials on the surface of the substrate to form a multilayer film structure; The specific multilayer film structure is:

[0037] Sub / 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S 88.54H261.73S 88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S88.54H 261.73S 88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H261.73S 88.54H 261.73S 88.54H261.73S 88.54H / Air, where H and S represent high-refractive-index materials and low-refractive-index materials respectively;

[0038] Step 4: During the deposition process, use an optical monitoring system to monitor the film thickness and optical properties in real time to ensure the uniformity and density of the film layer;

[0039] Step 5: Anneal the deposited film layer to eliminate the internal stress of the film layer and improve the stability and adhesion of the film layer;

[0040] Step 6: Deposit a protective layer on the surface of the film layer to improve the mechanical strength and environmental stability of the film layer.

[0041] Further, in Step 1, the optical substrate is quartz, and the thermal expansion coefficient of the substrate is less than 5x10 -6 / K.

[0042] Further, in Step 2, the high-refractive-index material is hafnium dioxide, and the refractive index range is 2.3.

[0043] Further, in Step 2, the low-refractive-index material is silicon dioxide, and the refractive index is 1.45.

[0044] Further, in Step 3, the physical vapor deposition technology is electron beam evaporation. The electron beam evaporation is to use an electron beam to heat and evaporate high-refractive-index materials and low-refractive-index materials and deposit them on the surface of the substrate.

[0045] Further, in step three, the chemical vapor deposition technology is plasma enhanced chemical vapor deposition, and during the deposition process, the stress distribution of the film layer is further optimized by adjusting the flow rate and pressure of the reaction gas.

[0046] Further, in step five, the annealing treatment is carried out at a temperature of 200 °C for 2 h to eliminate the internal stress in the film layer and improve the adhesion of the film layer.

[0047] Further, in step six, the protective layer is silicon dioxide with a thickness of 50 nm, and the deposition process parameters of the protective layer are the same as those of the low refractive index material to further reduce the process complexity and cost.

[0048] Further, in step two, the reflectivity of the multilayer film is greater than 99.9%, and the film layer stress is less than 100 MPa.

[0049] Example 2

[0050] Please refer to Figure 1 shown. The present invention proposes a technical solution for a laser mirror film layer preparation process: a laser mirror film layer preparation process, including the following steps:

[0051] Step one: Provide an optical substrate, and use ultrasonic waves to clean the surface of the substrate to remove the contaminants on the surface of the substrate, and then polish the substrate to ensure that the surface roughness is less than 1 nm to reduce the scattering loss;

[0052] Step two: According to the laser wavelength and reflectivity requirements, design a multilayer film structure, which is alternately composed of high refractive index materials and low refractive index materials, and the thickness of each layer of film is 1 / 4 of the laser wavelength;

[0053] Step three: Adopt physical vapor deposition or chemical vapor deposition technology to sequentially deposit high refractive index materials and low refractive index materials on the surface of the substrate to form a multilayer film structure; The specific multilayer film structure is:

[0054] Sub / 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S 88.54H261.73S 88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S88.54H 261.73S 88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H261.73S 88.54H 261.73S 88.54H261.73S 88.54H / Air, where H and S represent high refractive index material and low refractive index material respectively;

[0055] Step Four: During the deposition process, the film thickness and optical properties are monitored in real time through an optical monitoring system to ensure the uniformity and compactness of the film;

[0056] Step Five: Anneal the deposited film to eliminate the internal stress in the film and improve the stability and adhesion of the film;

[0057] Step Six: Deposit a protective layer on the film surface to improve the mechanical strength and environmental stability of the film.

[0058] Further, in Step One, the optical substrate is quartz, and the thermal expansion coefficient of the substrate is less than 5x10 -6 / K.

[0059] Further, in Step Two, the high refractive index material is hafnium dioxide, and the refractive index range is 2.4.

[0060] Further, in Step Two, the low refractive index material is silicon dioxide, and the refractive index is 1.48.

[0061] Further, in Step Three, the physical vapor deposition technique is magnetron sputtering; in the magnetron sputtering process, ions bombard the target, causing the high refractive index material and the low refractive index material to be sputtered and deposited on the surface of the substrate.

[0062] Further, in Step Three, the chemical vapor deposition technique is atomic layer deposition, and during the deposition process, the stress distribution of the film is further optimized by adjusting the flow rate and pressure of the reaction gas.

[0063] Further, in Step Five, the temperature of the annealing treatment is 400 °C and the time is 3 h to eliminate the internal stress in the film and improve the adhesion of the film.

[0064] Further, in step six, the protective layer is silicon nitride with a thickness of 60 nm, and the deposition process parameters of the protective layer are the same as those of the low refractive index material to further reduce process complexity and cost.

[0065] Further, in step two, the reflectivity of the multilayer film is greater than 99.9%, and the film stress is less than 100 MPa.

[0066] Example 3

[0067] Please refer to Figure 1 shown. The present invention proposes a technical solution for a laser mirror film preparation process: a laser mirror film preparation process, including the following steps:

[0068] Step one: Provide an optical substrate, clean the substrate surface using ultrasonic waves to remove contaminants on the substrate surface, and then polish the substrate to ensure that the surface roughness is less than 1 nm to reduce scattering loss;

[0069] Step two: According to the laser wavelength and reflectivity requirements, design a multilayer film structure, which is alternately composed of high refractive index materials and low refractive index materials, and the thickness of each layer of film is 1 / 4 of the laser wavelength;

[0070] Step three: Adopt physical vapor deposition or chemical vapor deposition technology to sequentially deposit high refractive index materials and low refractive index materials on the substrate surface to form a multilayer film structure; The specific multilayer film structure is:

[0071] Sub / 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S 88.54H261.73S 88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S88.54H 261.73S 88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H261.73S 88.54H 261.73S 88.54H261.73S 88.54H / Air, where H and S represent high refractive index materials and low refractive index materials respectively;

[0072] Step four: During the deposition process, the film thickness and optical properties are monitored in real time through an optical monitoring system to ensure the uniformity and density of the film;

[0073] Step Five: Anneal the deposited film layer to eliminate the internal stress in the film layer and improve the stability and adhesion of the film layer;

[0074] Step Six: Deposit a protective layer on the surface of the film layer to improve the mechanical strength and environmental stability of the film layer.

[0075] Further, in Step One, the optical substrate is quartz, and the thermal expansion coefficient of the substrate is less than 5x10 -6 / K.

[0076] Further, in Step Two, the high refractive index material is hafnium dioxide, and the refractive index range is 2.0 - 2.5.

[0077] Further, in Step Two, the low refractive index material is silicon dioxide, and the refractive index is 1.46.

[0078] Further, in Step Three, the physical vapor deposition technique is electron beam evaporation; the electron beam evaporation uses an electron beam to heat and evaporate the high refractive index material and the low refractive index material, which are deposited on the surface of the substrate.

[0079] Further, in Step Three, the chemical vapor deposition technique is plasma enhanced chemical vapor deposition, and during the deposition process, the stress distribution of the film layer is further optimized by adjusting the flow rate and pressure of the reaction gas.

[0080] Further, in Step Five, the temperature of the annealing treatment is 400 °C, and the time is 2 h to eliminate the internal stress in the film layer and improve the adhesion of the film layer.

[0081] Further, in Step Six, the protective layer is one of silicon dioxide or silicon nitride, with a thickness of 80 nm, and the deposition process parameters of the protective layer are the same as those of the low refractive index material to further reduce the process complexity and cost.

[0082] Further, in Step Two, the reflectivity of the multi-layer film is greater than 99.9%, and the film layer stress is less than 100 MPa.

[0083] This laser mirror is applicable to lasers with wavelengths of 1064 nm, 532 nm, or 355 nm, and the film layer design significantly reduces the demand for high refractive index materials by optimizing the usage ratio of low refractive index materials, thereby reducing the film material cost.

[0084] Advantages of the present invention:

[0085] (1) Reduce film material cost: In the traditional film layer design of laser mirrors, the matching ratio of high refractive index materials and low refractive index materials is usually 1:1, that is, the thickness and number of layers of the two materials are similar. High refractive index materials (such as Ta 2 O 5 、TiO2 etc.) are much higher in price than low refractive index materials (such as SiO 2 ). Generally, the price of high refractive index film materials is about 150 times that of low refractive index film materials. To reduce the film material cost, this technology adopts an innovative 1:2 matching ratio design, that is, the usage amount of low refractive index materials is 2 times that of high refractive index materials. Through this design, the demand for high refractive index film materials is significantly reduced, and at the same time, the usage ratio of low refractive index film materials is increased. This optimization not only meets the optical performance requirements of the mirror, but also can reduce the film material cost by about 30%, thus greatly improving the economy and market competitiveness of the product;

[0086] (2) Reduce processing time: During the film deposition process, the evaporation rate of low refractive index materials (such as SiO 2 ) is usually much faster than that of high refractive index materials (such as Ta 2 0 5 , TiO 2 ). The former is about 3 times that of the latter. Therefore, in the design with a 1:2 matching ratio, due to the increased usage ratio of low refractive index materials, the deposition time of the overall film layer is significantly shortened. When depositing a film layer of the same thickness, the fast evaporation characteristic of low refractive index materials can greatly improve production efficiency and reduce processing time. This not only reduces the equipment operation cost, but also improves the production capacity of the production line, creating higher economic benefits for the enterprise;

[0087] (3) Reduce film layer stress: Film layer stress is one of the key factors affecting the performance of laser mirrors. In traditional designs, due to the different stress characteristics of high refractive index materials and low refractive index materials, the film layer is prone to generate large internal stress, resulting in film layer cracking or peeling off. Through the 1:2 matching ratio design, this technology cleverly utilizes the mutual cancellation effect between the compressive stress of high refractive index materials and the tensile stress of low refractive index materials. This stress balance design not only effectively reduces the overall stress of the film layer, but also enables the film layer to be thick enough without cracking. At the same time, due to the more uniform stress distribution, the surface shape change rate of the mirror has also been significantly improved, ensuring the high-quality transmission of the laser beam;

[0088] (4) Improve film layer stability and optical performance: Through the 1:2 matching ratio design, the mechanical stability and optical performance of the film layer have been comprehensively improved. The increase in low refractive index materials not only reduces the film material cost and processing time, but also further enhances the laser damage resistance of the film layer due to its excellent stress characteristics and thermal stability. The increase in the thickness of the film layer does not lead to a significant increase in the surface shape change rate. Instead, through the stress cancellation effect, the film layer can still maintain stable optical performance under high temperature or high-power laser irradiation. This design meets the stringent requirements of laser mirrors in high-power applications.

[0089] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inner", "front", "center", "both ends", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0090] In the present invention, unless otherwise clearly specified and defined, terms such as "installed", "set", "connected", "fixed", "swiveling connection", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. It can be the communication inside two elements or the interaction relationship between two elements. Unless otherwise clearly defined, for those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0091] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A laser reflector film preparation process, characterized in that: The following steps are involved: Step 1: Provide an optical substrate and use ultrasound to clean the substrate surface to remove contaminants on the substrate surface, and then polish the substrate to ensure that the surface roughness is less than 1nm to reduce scattering loss; Step 2: Design a multilayer film structure according to the laser wavelength and reflectivity requirements. The multilayer film structure is composed of alternating high refractive index materials and low refractive index materials, and the thickness of each film layer is 1 / 4 of the laser wavelength; Step 3: Using physical vapor deposition or chemical vapor deposition technology, high refractive index material and low refractive index material are sequentially deposited on the surface of the substrate to form a multilayer film structure; the specific multilayer film structure is: Sub / 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S 88.54H261.73S 88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H 261.73S88.54H 261.73S 88.54H261.73S 88.54H 261.73S 88.54H 261.73S 88.54H261.73S 88.54H 261.73S 88.54H261.73S 88.54H / Air, where H and S represent high refractive index material and low refractive index material respectively; Step 4: During the deposition process, the film thickness and optical properties are monitored in real time through an optical monitoring system to ensure the uniformity and density of the film; Step 5: Annealing the deposited film layer to eliminate the internal stress of the film layer and improve the stability and adhesion of the film layer; Step 6: Deposit a protective layer on the surface of the film layer to improve the mechanical strength and environmental stability of the film layer.

2. The laser reflector film preparation process according to claim 1, characterized in that: In step 1, the optical substrate is quartz, and the thermal expansion coefficient of the substrate is less than 5x10 -6 / K.

3. The laser reflector film preparation process according to claim 1, characterized in that: In step 2, the high refractive index material is hafnium dioxide, and the refractive index ranges from 2.0 to 2.

5.

4. The laser reflector film preparation process according to claim 1, characterized in that: In step 2, the low refractive index material is silicon dioxide, and the refractive index is 1.45 to 1.

48.

5. The laser reflector film preparation process according to claim 1, characterized in that: In step three, the physical vapor deposition technology is one of electron evaporation or magnetron sputtering; the electron evaporation is to use electron beam heating to evaporate high refractive index materials and low refractive index materials, and deposit them on the surface of the substrate; the magnetron sputtering is to bombard the target material with ions, so that the high refractive index material and the low refractive index material are sputtered and deposited on the surface of the substrate.

6. The laser reflector film preparation process according to claim 1, characterized in that: In step three, the chemical vapor deposition technology is one of plasma enhanced chemical vapor deposition or atomic layer deposition, and the stress distribution of the film layer is further optimized by adjusting the reaction gas flow and pressure during the deposition process.

7. The laser reflector film preparation process according to claim 1, characterized in that: In step five, the annealing treatment is performed at a temperature of 200° C. to 500° C. for 1 to 4 hours to eliminate the internal stress of the film layer and improve the adhesion of the film layer.

8. The laser reflector film preparation process according to claim 1, characterized in that: In step six, the protective layer is one of silicon dioxide or silicon amide, with a thickness of 10 to 100 nm, and the deposition process parameters of the protective layer are the same as those of the low refractive index material to further reduce process complexity and cost.

9. The laser reflector film preparation process according to claim 1, characterized in that: In step 2, the reflectivity of the multilayer film is greater than 99.9%, and the film stress is less than 100 MPa.

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