Infrared detector broadband antireflection film based on multilayer optical stack

Abstract

The invention relates to the technical field of infrared detectors, and discloses an infrared detector broadband antireflection film based on multilayer optical stacks, which comprises the following specific steps: step 1, firstly determining an application waveband of the antireflection film, selecting antireflection film materials MgF2, Si and ZnSe, and taking a substrate material as GaSb; 2, according to the Fresnel law and the correlation theory of light waves, the amplitude of reflected waves and transmitted waves and the change of reflection phases when the light waves pass through different interfaces are researched, a reflectivity characteristic matrix of the multilayer film is solved through a correlation formula, and the refractive index and the absorption coefficient of the material are considered. By adopting the novel multilayer film design, the transmittance and waveband response of the infrared detector are remarkably improved, the antireflection film is not only suitable for short and medium wave infrared detectors, but also can be expanded to other photoelectric equipment, has wide application prospects and market potential, and by adopting the technology, the cost effectiveness can be maintained, and meanwhile, the cost performance of the infrared detector can be greatly improved. And the performance of the device and equipment is obviously improved.

Description

Technical Field

[0001] The invention relates to the technical field of infrared detectors, and in particular to a wide-band anti-reflection film for infrared detectors based on a multi-layer optical stack. Background Art

[0002] In modern optoelectronic devices, infrared detectors have important market value due to their wide applications in night vision, weather monitoring and medical diagnosis. These applications place higher requirements on the performance of detectors, especially in terms of optical transmittance and detection wavelength range. At present, the anti-reflection film technology used in most infrared detectors is still limited to a single layer or a few layers of film, which limits its light transmission efficiency and sensitivity over a wide band. Therefore, it is particularly important to develop an anti-reflection film technology that can effectively expand the working band and improve the transmittance.

[0003] Research on this technical point shows that existing anti-reflection films mostly rely on traditional materials and designs, such as a single MgF2 or ZnSe film layer. These structures have obvious limitations in multi-band light transmittance performance. The market demand for wide-band and high-efficiency light-transmitting films is increasing, prompting researchers to seek new solutions. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a wide-band anti-reflection film for infrared detectors based on a multi-layer optical stack to solve the problem.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a wide-band antireflection film for infrared detectors based on a multi-layer optical stack, comprising the following specific steps:

[0006] Step 1: First determine the application band of the anti-reflection film, select the anti-reflection film materials MgF2, Si, ZnSe, and the substrate material is GaSb;

[0007] Step 2: Based on Fresnel's law and related theories of light waves, study the amplitude of the reflected wave and the transmitted wave and the change of the reflected phase when the light wave passes through different interfaces, use the relevant formula to calculate the reflectivity characteristic matrix of the multilayer film, and consider the refractive index and absorption coefficient of the material to calculate the reflectivity and transmittance of the multilayer anti-reflection film;

[0008] Step 3: Use ethanol or acetone solvent to clean the GaSb substrate to ensure that there is no dust, grease or other contaminants on its surface;

[0009] Step 4: In the vacuum evaporation equipment, deposit each layer of material in the following order and thickness:

[0010] The first layer: high-purity MgF2, thickness is 255.7nm;

[0011] The second layer: high-purity Si, thickness is 13.1nm;

[0012] The third layer: high-purity ZnSe, thickness is 80.39nm;

[0013] The fourth layer: high-purity MgF2, thickness is 107.5nm;

[0014] The fifth layer: high-purity Si, thickness is 15.73nm;

[0015] The sixth layer: high-purity ZnSe, thickness is 35.78nm;

[0016] The seventh layer: high-purity MgF2, thickness is 14.54nm;

[0017] The eighth layer: high-purity Si, thickness is 85.01nm;

[0018] The deposition thickness and rate of each layer is computer controlled to ensure precise deposition;

[0019] Step 5: After each layer is deposited, the surface and optical properties are tested to ensure that each layer of material meets the design specifications. The transmittance and reflectivity curves of the GaSb substrate coated with the anti-reflection film in the 800-3000nm band are tested and analyzed, and the performance is compared with that of the substrate without anti-reflection film to evaluate the effect of the anti-reflection film.

[0020] Preferably, the antireflection film is applied to the 800-3000 nm band, and the arrangement order of the materials in the antireflection film is a specific multilayer structure.

[0021] Preferably, the antireflection film has an 8-layer structure, and the interference of light waves is controlled by optimizing the design of the multi-layer film structure to reduce reflection losses.

[0022] Preferably, the characteristic matrix of the reflectivity of the multilayer film is:

[0023]

[0024] Where: k is the number of film layers, δ j is the phase angle, η j is the equivalent refractive index.

[0025] Preferably, the reflectivity and transmittance of the multilayer antireflection film are:

[0026] R=(eta0B-C) / (eta0B+C)(eta0B-C) / (eta0B+C) *

[0027] T=(1-R)ψ

[0028] In the formula: ψ=Re(η s)Y * / Re(Y)BC * , where R is the reflectivity and T is the refractive index.

[0029] The present invention provides a wide-band antireflection film for infrared detectors based on a multi-layer optical stack, which has the following beneficial effects:

[0030] 1. The present invention significantly improves the transmittance and band response of infrared detectors by adopting a new multi-layer film design. This anti-reflection film is not only suitable for short- and medium-wave infrared detectors, but can also be extended to other optoelectronic devices. It has broad application prospects and market potential. Through this technology, the performance of devices and equipment can be significantly improved while maintaining cost-effectiveness.

[0031] 2. The present invention improves these key performance parameters and optimizes the key performance parameters to greatly improve the sensitivity of the detector. The detector can capture weak light signals more keenly, allowing the detector to work in a wider wavelength range, and the accuracy has also been significantly improved, effectively reducing the probability of misjudgment and error, ensuring the accuracy and reliability of the detection results, and improving sensitivity and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the film structure of a wide-band multilayer anti-reflection film for an infrared detector based on a multilayer optical stack according to the present invention;

[0033] Figure 2 A transmittance curve diagram of a GaSb substrate of a wide-band anti-reflection film for an infrared detector based on a multi-layer optical stack in the present invention in the 800-3000nm band when the present invention is not used;

[0034] Figure 3 The GaSb substrate of the infrared detector wide-band anti-reflection film based on the multi-layer optical stack of the present invention is not used Figure 1 The reflectivity curve of the multi-layer anti-reflection film structure in the 800-3000nm band;

[0035] Figure 4 The invention provides a wide-band antireflection film for infrared detectors based on a multi-layer optical stack. Figure 1 The transmittance curve of the multilayer antireflection film structure shown is in the range of 800 to 3000 nm when it is applied to a photoelectric device on a GaSb substrate;

[0036] Figure 5 The invention provides a wide-band antireflection film for infrared detectors based on a multi-layer optical stack. Figure 1 The multilayer antireflection film structure shown is a reflectivity curve in the 800-3000nm band when applied to an optoelectronic device on a GaSb substrate. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example:

[0039] Please see attached Figure 1 -Attached Figure 5 The embodiment of the present invention provides a wide-band antireflection film for infrared detectors based on a multi-layer optical stack, comprising the following specific steps:

[0040] Step 1: First determine the application band of the anti-reflection film, select the anti-reflection film materials MgF2, Si, ZnSe, and the substrate material is GaSb;

[0041] Step 2: Based on Fresnel's law and related theories of light waves, study the amplitude of the reflected wave and the transmitted wave and the change of the reflected phase when the light wave passes through different interfaces, use the relevant formula to calculate the reflectivity characteristic matrix of the multilayer film, and consider the refractive index and absorption coefficient of the material to calculate the reflectivity and transmittance of the multilayer anti-reflection film;

[0042] Step 3: Use ethanol or acetone solvent to clean the GaSb substrate to ensure that there is no dust, grease or other contaminants on its surface;

[0043] Step 4: In the vacuum evaporation equipment, deposit each layer of material in the following order and thickness:

[0044] The first layer: high-purity MgF2, thickness is 255.7nm;

[0045] The second layer: high-purity Si, thickness is 13.1nm;

[0046] The third layer: high-purity ZnSe, thickness is 80.39nm;

[0047] The fourth layer: high-purity MgF2, thickness is 107.5nm;

[0048] The fifth layer: high-purity Si, thickness is 15.73nm;

[0049] The sixth layer: high-purity ZnSe, thickness is 35.78nm;

[0050] The seventh layer: high-purity MgF2, thickness is 14.54nm;

[0051] The eighth layer: high-purity Si, thickness is 85.01nm;

[0052] The deposition thickness and rate of each layer is computer controlled to ensure precise deposition;

[0053] Step 5: After each layer is deposited, the surface and optical properties are tested to ensure that each layer of material meets the design specifications. The transmittance and reflectivity curves of the GaSb substrate coated with the anti-reflection film in the 800-3000nm band are tested and analyzed, and the performance is compared with that of the substrate without anti-reflection film to evaluate the effect of the anti-reflection film.

[0054] The anti-reflection film is used in the 800-3000nm band. The arrangement order of the materials in the anti-reflection film is a specific multi-layer structure.

[0055] The anti-reflection film has an 8-layer structure, and the interference of light waves is controlled through the optimized design of the multi-layer film structure to reduce reflection losses.

[0056] The characteristic matrix of the reflectivity of the multilayer film is:

[0057]

[0058] Where: k is the number of film layers, δ j is the phase angle, η j is the equivalent refractive index.

[0059] The reflectivity and transmittance of the multilayer antireflection coating are:

[0060] R=(eta0B-C) / (eta0B+C)(eta0B-C) / (eta0B+C) *

[0061] T=(1-R)ψ

[0062] In the formula: ψ=Re(η s )Y * / Re(Y)BC * , where R is the reflectivity and T is the refractive index.

[0063] The following is an introduction in conjunction with specific embodiments:

[0064] Embodiment 1:

[0065] According to the above preparation method, a wide-band antireflection film for infrared detectors based on a multilayer optical stack was prepared. The performance of the prepared antireflection film was tested to obtain its transmittance and reflectance curves in the 2000nm band. The results showed that the highest transmittance was 99.7%, the average transmittance was as high as 98.18%, the lowest reflectance was 0.2% at 2550nm, and the average reflectance dropped to 1.66%.

[0066] Embodiment 2:

[0067] The prepared infrared detector wide-band anti-reflection film based on multi-layer optical stack was applied to the actual infrared detector, and the performance was compared with the detector without the anti-reflection film. The average transmittance of the detector without the anti-reflection film in the 3000nm band is only 24%, and the maximum does not exceed 36%, while the average transmittance of the detector using the anti-reflection film of the present invention in the same band is as high as more than 98%, and the maximum is close to 100%. At the same time, in terms of the detector light response, the performance of the detector after using the anti-reflection film has also been significantly improved, proving the significant advantages of the present invention in practical applications.

[0068] like Figure 2 As shown, the average transmittance of the infrared detector substrate without anti-reflection film is only 24%, and the highest is only 36%.

[0069] like Figure 3 As shown, the average reflectivity of the infrared detector substrate without anti-reflection film is 40%, and the highest is close to 60%.

[0070] like Figure 4 As shown, when the present invention is applied to optoelectronic devices, the highest transmittance is 99.7%, the average transmittance is as high as 98.18%, and the maximum transmittance is close to 100%, indicating that there is almost no loss of incident light in a specific wavelength band.

[0071] like Figure 5 As shown, when the present invention is applied to optoelectronic devices, the minimum reflectivity is 0.2% at 2550nm, the average reflectivity is reduced to 1.66%, and the minimum reflectivity is close to 0%, which effectively reduces the loss of light energy. This shows that there is almost no loss of incident light in a specific wavelength band.

[0072] The anti-reflection film design optimizes the optical performance in the short to medium-wave infrared bands, and proposes a multi-layer structure to significantly improve the light transmittance and reflectivity of infrared detectors. From the provided curve graph, it can be seen that it is expected to greatly improve the optical performance of infrared detectors in the 800 to 3000 nanometer band. The lowest reflectivity of the anti-reflection film is 0.2% at 2550nm, the highest transmittance is 99.7%, the average transmittance is as high as 98.18%, and the maximum transmittance is close to 100%, indicating that there is almost no loss of incident light in a specific band; the average reflectivity is reduced to 1.66%, and the minimum reflectivity is close to 0%, effectively reducing the loss of light energy. In comparison, the average transmittance of the infrared detector substrate without anti-reflection film is only 24%, the highest is only 36%, and the average reflectivity is 40%, and the highest is close to 60%.

[0073] Reflectivity without AR coating: In contrast, the substrate without AR coating shows a periodic reflectivity variation of up to 60% in the range of 800 to 1200 nm, indicating a significant loss of incident light without AR coating. Transmission without AR coating: The substrate without AR coating shows great instability in transmittance, with the transmittance dropping to less than 15% at some wavelengths, indicating that the light suffers severe attenuation without AR coating.

[0074] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a wide-band antireflection film for an infrared detector based on a multi-layer optical stack, characterized in that: The specific steps include: Step 1: First determine the application band of the anti-reflection film, select the anti-reflection film material MgF2, Si, ZnSe, and the substrate material is GaSb; Step 2: Based on Fresnel's law and related theories of light waves, study the amplitude of the reflected wave and the transmitted wave and the change of the reflected phase when the light wave passes through different interfaces, use the relevant formula to calculate the reflectivity characteristic matrix of the multilayer film, and consider the refractive index and absorption coefficient of the material to calculate the reflectivity and transmittance of the multilayer anti-reflection film; Step 3: Use ethanol or acetone solvent to clean the GaSb substrate to ensure that there is no dust, grease or other contaminants on its surface; Step 4: In the vacuum evaporation equipment, deposit each layer of material in the following order and thickness: The first layer: high-purity MgF2, thickness is 255.7nm; Second layer: high-purity Si, thickness 13.1nm; The third layer: high-purity ZnSe, thickness is 80.39nm; The fourth layer: high-purity MgF2, thickness is 107.5nm; Fifth layer: high-purity Si, thickness is 15.73nm; The sixth layer: high-purity ZnSe, thickness is 35.78nm; The seventh layer: high-purity MgF2, thickness is 14.54nm; The eighth layer: high-purity Si, thickness is 85.01nm; The deposition thickness and rate of each layer is computer controlled to ensure precise deposition; Step 5: After each layer is deposited, the surface and optical properties are tested to ensure that each layer of material meets the design specifications. The transmittance and reflectivity curves of the GaSb substrate coated with the anti-reflection film in the 800-3000nm band are tested and analyzed, and the performance is compared with that of the substrate without anti-reflection film to evaluate the effect of the anti-reflection film.

2. The infrared detector wide-band antireflection film based on multi-layer optical stack according to claim 1, characterized in that: The anti-reflection film is applied to the 800-3000nm waveband. The arrangement order of the materials in the anti-reflection film is a specific multi-layer structure.

3. The infrared detector wide-band antireflection film based on multi-layer optical stack according to claim 1, characterized in that: The anti-reflection film has an 8-layer structure, and the interference of light waves is controlled by optimizing the design of the multi-layer film structure to reduce reflection loss.

4. The infrared detector wide-band antireflection film based on multi-layer optical stack according to claim 1, characterized in that: The characteristic matrix of the reflectivity of the multilayer film is: Where: k is the number of film layers, δ j is the phase angle, η j is the equivalent refractive index.

5. The infrared detector wide-band antireflection film based on multi-layer optical stack according to claim 1, characterized in that: The reflectivity and transmittance of the multilayer antireflection film are: R=[(η0B-C) / (η0B+C)][(η0B-C) / (η0B+C)] * T=(1-R)ψ In the formula: ψ=Re(η s )Y * / Re(Y)BC * , where R is the reflectivity and T is the refractive index.

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