Wide-temperature-range high-performance anti-laser reflecting film and preparation method thereof
By designing a wide temperature zone high-performance anti-laser reflective film, combined with superconducting film and high-low refractive index multi-layer dielectric reflection stack, the problems of insufficient anti-laser damage ability and poor environmental adaptability under high-energy density lasers are solved, and the high reflectivity and anti-laser damage performance in a wide temperature zone are achieved, which improves the stability of the optical system.
Patent Information
- Application Number
- CN202510783579.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-12
- Publication Date
- 2025-07-11
AI Technical Summary
Traditional high-reflective films have insufficient ability to resist laser damage under high energy density laser irradiation, poor environmental adaptability, and low thermal management performance, making it difficult to maintain stable performance in a wide temperature zone.
A wide temperature zone high-performance anti-laser reflective film is adopted, including the substrate, the first and second superconducting functional layers, and a high and low refractive index multi-layer dielectric reflection stack. Reflectivity regulation is achieved through the superconducting state-normal state phase change characteristics, and a multi-layer composite structure design combining the superconducting film and a high and low refractive index multi-layer dielectric reflection stack.
Maintain excellent anti-laser damage performance and high reflectivity in the wide temperature zone of 4K-300K, the laser damage threshold is increased, and the superconducting film provides electromagnetic shielding function, which significantly improves the environmental stability of the optical system.
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Figure CN120294888A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of optical thin films, and particularly to an optical element that needs to have the characteristics of a wide temperature range, high reflectivity, and anti-laser damage in a high-power laser system. Background Art
[0002] As a key optical element of a laser system, a high-reflection thin film plays an irreplaceable and important role in fields such as national defense and military industry, industrial manufacturing, and communication technology. With the continuous increase of laser power and the increasing complexity of the application environment, traditional high-reflection thin film technology is facing severe performance challenges. The specific manifestations are several core problems: First, the anti-laser damage ability is insufficient. For multi-layer dielectric films represented by Ta2O5 / SiO2, under continuous irradiation of high-energy density lasers (>1GW / cm²), the film layer structure will be damaged due to the thermal accumulation effect; Second, the environmental adaptability is poor. Under the extreme temperature difference of -150°C to +150°C experienced by spacecraft or the ultra-wide temperature range conditions of 4K - 300K faced by deep space exploration, problems such as reflectivity attenuation, stress cracking, and even overall peeling of the thin film are likely to occur; Third, the thermal management efficiency is low. The thermal conductivity of traditional high-reflection films is generally lower than 10W / (m·K), making it difficult to achieve rapid dissipation of laser energy and requiring improvement. Summary of the Invention
[0003] The main technical problem to be solved by the present invention is to provide a high-performance anti-laser reflection film with a wide temperature range and its preparation method, which has the characteristics of a wide temperature range and high reflectivity and improves the performance of resisting laser damage.
[0004] To solve the above technical problems, a technical solution adopted by the present invention is: to provide a high-performance anti-laser reflection film with a wide temperature range, including: a substrate, a first superconducting functional layer, a high-low refractive index multi-layer dielectric reflection stack, and a second superconducting functional layer. The first superconducting functional layer is disposed above the substrate, the high-low refractive index multi-layer dielectric reflection stack is disposed above the first superconducting functional layer, and the second superconducting functional layer is disposed above the high-low refractive index multi-layer dielectric reflection stack. The first superconducting functional layer and the second superconducting functional layer both adopt low-temperature superconducting thin films or both adopt high-temperature superconducting thin films.
[0005] In a preferred embodiment of the present invention, the material of the low-temperature superconducting thin film is one of Nb, NbN, and NbTi, and the material of the high-temperature superconducting thin film is one of YBCO and MgB2.
[0006] In a preferred embodiment of the present invention, a metal transition layer is disposed on the top surface of the substrate.
[0007] In a preferred embodiment of the present invention, the metal transition layer is a titanium thin film with a thickness of 9 to 11 nanometers.
[0008] In a preferred embodiment of the present invention, the material of the substrate is one of Si / SiO2, optical glass, fused quartz, strontium titanate, sapphire, and magnesium oxide.
[0009] In a preferred embodiment of the present invention, when the material of the substrate is strontium titanate, both the first superconducting functional layer and the second superconducting functional layer are high-temperature superconducting thin films.
[0010] In a preferred embodiment of the present invention, the high-low refractive index multi-layer dielectric reflection stack includes alternately deposited high-refractive index layers and low-refractive index layers. Among them, the material of the high-refractive index layer is selected from one or more of tantalum pentoxide, titanium dioxide, and hafnium dioxide, and the material of the low-refractive index layer is selected from one or more of silicon dioxide and aluminum oxide.
[0011] To solve the above technical problems, another technical solution adopted by the present invention is: to provide a method for preparing a reflective film, including the following steps: a. Substrate selection and pretreatment, performing a cleaning treatment; b. Depositing a metal transition layer on the substrate; c. Depositing a first superconducting functional layer on the metal transition layer; d. Depositing a high-low refractive index multi-layer dielectric reflection stack on the first superconducting functional layer; e. Preparing a second superconducting functional layer on the high-low refractive index multi-layer dielectric reflection stack; f. Post-annealing treatment, annealing at a constant temperature of 300 °C for 1 hour in high-purity argon.
[0012] To solve the above technical problems, yet another technical solution adopted by the present invention is: to provide a method for preparing a reflective film, including the following steps: a. Selection and pretreatment of the substrate; b. Depositing a first superconducting functional layer on the substrate; c. Depositing a high-low refractive index multi-layer dielectric reflection stack on the first superconducting functional layer; d. Preparing a second superconducting functional layer on the high-low refractive index multi-layer dielectric reflection stack; e. Post-annealing treatment.
[0013] In a preferred embodiment of the present invention, the first superconducting functional layer and the second superconducting functional layer are high-temperature superconducting thin films.
[0014] The beneficial effects of the present invention are as follows: A high-performance anti-laser reflection film with a wide temperature range and its preparation method proposed by the present invention adopt a multi-layer composite structure design that combines superconducting thin films with high- and low-refractive-index multi-layer dielectric reflection stacks. Through the superconducting state-normal state phase transition characteristics, intelligent regulation of the reflectivity is achieved, and a cooperative working mechanism for different working temperature ranges is realized, breaking through the limitation of poor temperature range adaptability of traditional high-performance reflection films. It can work stably in the wide temperature range of 4K - 300K, maintain excellent anti-laser damage performance in the wide temperature range (LIDT > 15 J / cm², 1064 nm, 10 ns), and the reflectivity in a specific wavelength range can reach more than 99.5%. At the same time, the introduction of superconducting thin films also endows it with excellent electromagnetic shielding function, significantly improving the environmental stability of the optical system. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, where: Figure 1 is a flowchart of a preferred embodiment of the preparation method of a reflection film of the present invention; Figure 2 is a schematic structural diagram of a substrate adopted in the preparation method of a reflection film of the present invention in a preferred embodiment; Figure 3 is a schematic structural diagram of a preferred embodiment after depositing a metal transition layer on the substrate in the preparation method of a reflection film of the present invention; Figure 4 is a schematic structural diagram of a preferred embodiment after depositing a first superconducting functional layer on the metal transition layer in the preparation method of a reflection film of the present invention; Figure 5 is a schematic structural diagram of a preferred embodiment after depositing a high- and low-refractive-index multi-layer dielectric reflection stack on the first superconducting functional layer in the preparation method of a reflection film of the present invention; Figure 6 is a schematic structural diagram of a preferred embodiment after depositing a second superconducting functional layer on the high- and low-refractive-index multi-layer dielectric reflection stack in the preparation method of a reflection film of the present invention; Figure 7 is a schematic structural diagram of a preferred embodiment of the post-annealing treatment process in the preparation method of a reflection film of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.
[0017] Please refer to Figures 1 to 7 , the embodiments of the present invention include: Such as Figure 6 shown, a high-performance anti-laser reflection film with a wide temperature range, including: a substrate 101, a first superconducting functional layer 301, a high-low refractive index multi-layer dielectric reflection stack 401, and a second superconducting functional layer 501. The first superconducting functional layer 301 and the second superconducting functional layer 501 both adopt low-temperature superconducting thin films or both adopt high-temperature superconducting thin films. The material of the low-temperature superconducting thin film is selected from one of Nb, NbN, and NbTi, and the material of the high-temperature superconducting thin film is selected from one of YBCO and MgB2, and is selected according to the actual working temperature requirements.
[0018] Superconducting materials such as Nb, NbN, and YBCO exhibit unique temperature response characteristics: in the superconducting state (T < Tc), their surface resistance is lower than 10 μΩ, and the reflectivity to 1064 nm laser can reach more than 99.99%; while in the normal state (T > Tc), more than 90% of the laser energy can be absorbed through the plasma resonance effect. This intrinsic property provides a new idea for the development of anti-laser high-reflection films with a wide temperature range.
[0019] The material of the substrate 101 is selected from one of Si / SiO2, optical glass, fused quartz, strontium titanate, sapphire, and magnesium oxide, and the selection is relatively flexible. Among them, when the material of the substrate 101 is strontium titanate, the first superconducting functional layer 301 and the second superconducting functional layer 501 both adopt high-temperature superconducting thin films.
[0020] When other materials are selected for the material of the substrate 101, the first superconducting functional layer 301 and the second superconducting functional layer 501 both adopt low-temperature superconducting thin films. At this time, in order to improve the adhesion, a metal transition layer 201 also needs to be set. Such as Figure 3 shown, a metal transition layer 201 is provided on the top surface of the substrate 101. In this embodiment, the metal transition layer 201 adopts a titanium thin film with a thickness of 9 - 11 nanometers, which has both excellent adhesion performance and chemical stability. The metal transition layer 201 can be deposited on the top surface of the substrate 101 by physical vapor deposition processes such as electron beam evaporation, thermal evaporation, ion beam sputtering, and magnetron sputtering.
[0021] Figures 4 to 5As shown, the first superconducting functional layer 301 is disposed above the substrate 101, and the high and low refractive index multi-layer dielectric reflection stack 401 is disposed above the first superconducting functional layer 301. In this embodiment, the high and low refractive index multi-layer dielectric reflection stack includes alternately deposited high refractive index layers and low refractive index layers. Among them, the material of the high refractive index layer is selected from one or more of tantalum pentoxide, titanium dioxide, and hafnium dioxide, and the material of the low refractive index layer is selected from one or more of silicon dioxide and aluminum oxide, and the high refractive index layer and the low refractive index layer are alternately deposited.
[0022] Figure 6 As shown, the second superconducting functional layer 501 is disposed above the high and low refractive index multi-layer dielectric reflection stack 401. The deposition processes of the first superconducting functional layer 301 and the second superconducting functional layer 501 can adopt physical vapor deposition techniques such as magnetron sputtering, electron beam evaporation, or pulsed laser deposition. During the deposition process, the background vacuum degree needs to be controlled below 5×10 -5 Pa to ensure the superconducting properties of the superconducting thin film.
[0023] When the working temperature is higher than the critical temperature Tc of the superconducting functional layer, the first superconducting functional layer 301 and the second superconducting functional layer 501 exhibit metallic properties, and with their excellent thermal conductivity, they can achieve rapid dissipation of laser energy, significantly improving the laser damage threshold of the high-performance anti-laser reflection film in a wide temperature range. At this time, the structure of the high and low refractive index multi-layer dielectric reflection stack 401 mainly plays a high reflection function; When the working temperature is lower than the critical temperature Tc of the superconducting functional layer, the first superconducting functional layer 301 and the second superconducting functional layer 501 turn into the superconducting state. The superconducting thin film not only exhibits extremely high intrinsic reflection characteristics, but also its unique defect structure can generate a flux pinning effect, greatly improving the anti-laser damage ability and thermal diffusion efficiency of the thin film, and ensuring the stable reflection performance of the high-performance anti-laser reflection film in a wide temperature range under low temperature conditions.
[0024] Example 1 (both the first superconducting functional layer 301 and the second superconducting functional layer 501 use high-temperature superconducting thin films): A method for preparing a reflection film includes the following steps: Substrate selection and pretreatment: Select strontium titanate (SrTiO3) as the substrate 101, place it in an ultrasonic cleaner, and wash it with deionized water and ethanol for 10 minutes in sequence to remove surface impurities; subsequently, place the substrate 101 in a plasma cleaner for plasma treatment to further activate the substrate surface; Deposition of the first superconducting functional layer 301: Use pulsed laser deposition (PLD) technology to epitaxially grow a YBCO high-temperature superconducting thin film on the substrate 101 made of SrTiO3, with a laser energy density of 2J / cm 2, with an oxygen pressure of 0.1 mbar, a substrate temperature of 700 °C, and a deposition rate of 0.1 nm / s, a first superconducting functional layer 301 with a thickness of 150 nm is obtained; Deposition of the high and low refractive index multi-layer dielectric reflection stack 401: Using the ion beam assisted deposition (IBAD) technique, high refractive index thin film Ta2O5 and low refractive index thin film SiO2 are alternately deposited on the first superconducting functional layer 301 to form a 10-pair high and low refractive index multi-layer dielectric reflection stack structure. In this embodiment, the background vacuum degree is < 1×10-4 Pa, the deposition rate of each thin film is about 0.2 nm / s, the thickness of each layer of Ta2O5 is 120 nm, and the thickness of each layer of SiO2 is 180 nm; Preparation of the second superconducting functional layer 501: Using the pulsed laser deposition (PLD) technique, a YBCO high temperature superconducting thin film is deposited on the high and low refractive index multi-layer dielectric reflection stack 401, and the laser energy density is 2 J / cm 2 , with an oxygen pressure of 0.1 mbar, a substrate temperature of 700 °C, and a deposition rate of 0.1 nm / s, a second superconducting functional layer 501 with a thickness of 150 nm is obtained; Figure 7 As shown, post-treatment process: The prepared thin film is placed in a high-purity argon furnace, annealed at a temperature of 300 °C for 1 hour, and then cooled to eliminate stress and reduce the defect density, improving the densification and laser damage threshold of the thin film.
[0025] Example 2 (both the first superconducting functional layer 301 and the second superconducting functional layer 501 use low temperature superconducting thin films): A method for preparing a reflective film, comprising the following steps: Substrate selection and pretreatment: Sapphire is selected as the substrate 101, which is placed in an ultrasonic cleaner and sequentially cleaned with deionized water and acetone for 15 minutes to remove surface impurities; Subsequently, the substrate 101 is placed in a plasma cleaner for plasma treatment to further activate the substrate surface; Deposition of the first metal transition layer 201: Using the magnetron sputtering deposition technique, a 10-nm-thick metal thin film titanium (Ti) is deposited on the treated substrate 101 as a transition layer. In this embodiment, the magnetron sputtering power is 200 W, the argon gas pressure is 0.2 Pa, and the deposition rate is about 0.3 nm / s; Deposition of the first superconducting functional layer 301: Using the magnetron sputtering technique, an Nb low temperature superconducting thin film is deposited on the first metal transition layer 201. The purity of the Nb target is as high as 99.99%, the background vacuum degree is < 5×10-5 Pa, the sputtering power is 200 W, the argon gas pressure is 0.3 Pa, and the deposition rate is 0.5 nm / s, obtaining a first superconducting functional layer 301 with a thickness of 150 nm; Deposition of the high and low refractive index multi-layer dielectric reflection stack 401: Using the ion beam assisted deposition (IBAD) technique, high refractive index thin films Ta2O5 and low refractive index thin films SiO2 are alternately deposited on the first superconducting functional layer 301 to form a 10-pair high and low refractive index multi-layer dielectric reflection stack structure. In this embodiment, the background vacuum degree is <1×10-4 Pa, the deposition rate of each thin film is about 0.2 nm / s, the thickness of each Ta2O5 layer is 120 nm, and the thickness of each SiO2 layer is 180 nm; Deposition of the second superconducting functional layer 501: Using the magnetron sputtering technique, an Nb low-temperature superconducting thin film is deposited on the high and low refractive index multi-layer dielectric reflection stack 401. In this embodiment, the purity of the Nb target is as high as 99.99%, the background vacuum degree is <5×10-5 Pa, the sputtering power is 200 W, the argon gas pressure is 0.3 Pa, the deposition rate is 0.5 nm / s, and the second superconducting functional layer 501 with a thickness of 150 nm is obtained; Annealing post-treatment process: The prepared thin film is placed in a high-purity argon furnace and annealed at a temperature of 300 °C for 1 hour to eliminate stress and reduce the defect density, and improve the compactness and laser damage threshold of the thin film.
[0026] The prepared reflection films in Example 1 and Example 2 are tested, and the results are as follows: Reflectivity: When the working temperature T = 300 K, the reflectivity of the reflection film in Example 1 at a wavelength of 1064 nm is 99.5%, and the reflectivity of the reflection film in Example 2 at a wavelength of 1064 nm is 99.6%; When the working temperature T = 4 K, the reflectivity of the reflection film in Example 1 at a wavelength of 1064 nm is 99.6%, and the reflectivity of the reflection film in Example 2 at a wavelength of 1064 nm is 99.7%; Laser damage threshold: When the working temperature T = 300 K, the laser damage threshold of the reflection film in Example 1 reaches 16 J / cm² (1064 nm, 10 ns pulse), and the laser damage threshold of the reflection film in Example 2 reaches 18 J / cm² (1064 nm, 10 ns pulse); When the working temperature T = 4 K, the laser damage threshold of the reflection film in Example 1 reaches 25 J / cm² (1064 nm, 10 ns pulse), and the laser damage threshold of the reflection film in Example 2 reaches 28 J / cm² (1064 nm, 10 ns pulse).
[0027] In summary, a high-performance anti-laser reflection film with a wide temperature range and its preparation method proposed by the present invention can effectively improve the reflectivity, anti-laser damage performance, and working temperature range of optical thin films by optimizing the multi-layer film structure and superconducting layer design, meet the high requirements of high-power laser systems for optical components, and have a wider scope of application.
[0028] The above are only embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification of the present invention, or directly or indirectly applied in other related technical fields, shall similarly be included in the patent protection scope of the present invention.
Claims
1. A high-performance anti-laser reflection film with a wide temperature range, characterized in that Comprising: A substrate, a first superconducting functional layer, a high-low refractive index multi-layer dielectric reflection stack, and a second superconducting functional layer. The first superconducting functional layer is disposed above the substrate, the high-low refractive index multi-layer dielectric reflection stack is disposed above the first superconducting functional layer, and the second superconducting functional layer is disposed above the high-low refractive index multi-layer dielectric reflection stack. The first superconducting functional layer and the second superconducting functional layer are both made of low-temperature superconducting thin films or both made of high-temperature superconducting thin films.
2. The high-performance anti-laser reflection film with a wide temperature range according to claim 1, wherein The material of the low-temperature superconducting thin film is one of Nb, NbN, and NbTi, and the material of the high-temperature superconducting thin film is one of YBCO and MgB2.
3. The high-performance anti-laser reflection film with a wide temperature range according to claim 1, characterized in that A metal transition layer is provided on the top surface of the substrate.
4. The high-performance anti-laser reflection film with a wide temperature range according to claim 3, characterized in that The metal transition layer is made of a titanium thin film with a thickness of 9 to 11 nanometers.
5. The high-performance anti-laser reflection film with a wide temperature range according to claim 1, wherein The material of the substrate is one of Si / SiO2, optical glass, fused quartz, strontium titanate, sapphire, and magnesium oxide.
6. The high-performance anti-laser reflection film with a wide temperature range according to claim 5, wherein When the material of the substrate is strontium titanate, the first superconducting functional layer and the second superconducting functional layer are both made of high-temperature superconducting thin films.
7. The high-performance anti-laser reflection film with a wide temperature range according to claim 1, wherein The high-low refractive index multi-layer dielectric reflection stack includes alternately deposited high-refractive index layers and low-refractive index layers. Among them, the material of the high-refractive index layer is selected from one or more of tantalum pentoxide, titanium dioxide, and hafnium dioxide, and the material of the low-refractive index layer is selected from one or more of silicon dioxide and aluminum oxide.
8. A method for preparing a reflective film, which is used for preparing the high-performance anti-laser reflective film with a wide temperature range according to any one of claims 1 to 7, and is characterized in that, Comprising the following steps: a. Substrate selection and pretreatment; b. Depositing a metal transition layer on the substrate; c. Depositing a first superconducting functional layer on the metal transition layer; d. Depositing a high-low refractive index multi-layer dielectric reflection stack on the first superconducting functional layer; e. Fabricating a second superconducting functional layer on the high-low refractive index multi-layer dielectric reflection stack; f. Post-annealing treatment.
9. A method for preparing a reflective film, characterized in that, Comprising the following steps: a. Substrate selection and pretreatment; b. Depositing a first superconducting functional layer on the substrate; c. Depositing a high-low refractive index multi-layer dielectric reflection stack on the first superconducting functional layer; d. Fabricating a second superconducting functional layer on the high-low refractive index multi-layer dielectric reflection stack; e. Post-annealing treatment.
10. The preparation method of the reflective film according to claim 9, which is used for the preparation of the wide-temperature-range high-performance anti-laser reflective film according to any one of claims 1 to 7, is characterized in that, The first superconducting functional layer and the second superconducting functional layer are made of high-temperature superconducting thin films.