Deep Ultraviolet-Visible-Near Infrared Ultra-Broadband Band Absorber and Its Preparation Method

Abstract

The present invention belongs to the technical field of electromagnetic wave absorption, and particularly relates to a deep ultraviolet-visible-near infrared ultra-wideband band absorber and a preparation method thereof. The present invention provides a deep ultraviolet-visible-near infrared ultra-wideband band absorber, which comprises a substrate, a metal thin film reflection layer and a functional layer stacked in sequence from bottom to top; the functional layer comprises a plurality of dielectric absorption layers with decreasing complex refractive index from bottom to top. The present invention utilizes a thin film stack structure, which has the characteristics of polarization insensitivity and angle insensitivity. Moreover, the obtained band absorber has an extremely wide absorption bandwidth, and the band range is from 190 to 1700 nm.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic wave absorption, and particularly relates to a deep ultraviolet-visible-near infrared ultra-wideband absorber and a preparation method thereof. Background Art

[0002] The deep ultraviolet-visible-near infrared ultra-wideband absorber is an ultra-wideband high-absorption device, which has broad application prospects in many fields such as photoelectric detection, ultraviolet protection, thermal emitters, and stealth.

[0003] Traditional deep ultraviolet-visible-near infrared ultra-wideband absorbers are mainly planar thin film stacks or artificial metamaterial surface micro-nano structures. The thin film stack form is used to expand the absorption bandwidth, but the main disadvantage of this form is that the thickness is greater than 250 nm, which is not conducive to the integration of the absorber. The artificial metamaterial surface micro-nano structure can use a variety of plasmons to expand the absorption bandwidth. The main disadvantages of the ultra-wideband high-absorption achieved by this method are high processing costs and high angle sensitivity. Currently designed absorbers are difficult to simultaneously meet the characteristics of wide operating frequency, polarization insensitivity, and angle insensitivity. Summary of the Invention

[0004] The purpose of the present invention is to provide a deep ultraviolet-visible-near infrared ultra-wideband absorber and a preparation method thereof. The deep ultraviolet-visible-near infrared ultra-wideband absorber provided by the present invention has the characteristics of wide operating frequency, polarization insensitivity, and angle insensitivity.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a deep ultraviolet-visible-near infrared ultra-wideband absorber, including a substrate, a metal thin film reflection layer, and a functional layer stacked in sequence from bottom to top;

[0007] The functional layer includes multiple dielectric absorption layers with decreasing complex refractive index from bottom to top.

[0008] Preferably, the material of the metal thin film reflection layer includes one or more of Ti, Al, Ni, Au, and Ag.

[0009] Preferably, the thickness of the metal thin film reflection layer is greater than 50 nm.

[0010] Preferably, the material of the functional layer includes tungsten oxide.

[0011] Preferably, each dielectric absorption layer simultaneously satisfies the following three conditions:

[0012] The refractive index under ultraviolet light is 1.8 - 2.63, and the extinction coefficient is 0.06 - 1.22. The wavelength range of the ultraviolet light is 193 - 400 nm; the refractive index under visible light is 2.04 - 2.78, and the extinction coefficient is 0.06 - 0.78. The wavelength range of the visible light is 400 - 800 nm; the refractive index under near-infrared light is 2.05 - 3.25, and the extinction coefficient is 0.2 - 0.81. The wavelength range of the near-infrared light is 800 - 1690 nm.

[0013] Preferably, the total thickness of the multi-layer dielectric absorption layer is 90 - 200 nm.

[0014] Preferably, the thickness of each layer of the dielectric absorption layer is 8 - 50 nm.

[0015] Preferably, the absorption band range of the deep ultraviolet-visible-near infrared ultra-wideband absorber is 190 - 1700 nm.

[0016] The present invention also provides a preparation method of the deep ultraviolet-visible-near infrared ultra-wideband absorber described in the above technical solution, including the following steps:

[0017] A metal thin film reflection layer and a functional layer are sequentially prepared on the surface of the substrate.

[0018] Preferably, the preparation method of the metal thin film reflection layer is electron beam evaporation deposition;

[0019] The preparation method of the functional layer is magnetron sputtering.

[0020] The present invention provides a deep ultraviolet-visible-near infrared ultra-wideband absorber, including a substrate, a metal thin film reflection layer and a functional layer which are sequentially stacked from bottom to top; the functional layer includes a multi-layer dielectric absorption layer with sequentially decreasing complex refractive index from bottom to top. The present invention utilizes a thin film stack structure, which has the characteristics of polarization insensitivity and angle insensitivity. Moreover, the obtained band absorber has an extremely wide absorption bandwidth, and the band range is from 190 - 1700 nm.

[0021] The present invention also provides a preparation method of the deep ultraviolet-visible-near infrared ultra-wideband absorber described in the above technical solution, including the following steps: A metal thin film reflection layer and a functional layer are sequentially prepared on the surface of the substrate. The present invention does not require photolithography, thus avoiding the problem of high micro-nano manufacturing cost and providing the possibility of large-area preparation. When preparing each layer of the dielectric absorption layer, the complex refractive index and thickness are adjusted, and then the absorption characteristics in different bands are regulated for deep ultraviolet-visible-near infrared light absorption. Description of the Drawings

[0022] Figure 1Schematic structural diagram of the deep ultraviolet-visible-near infrared ultra-wideband absorber provided by the present invention, where 1 is the substrate, 2 is the metal thin film reflection layer, and 3 is the functional layer;

[0023] Figure 2 Schematic structural diagram of the deep ultraviolet-visible-near infrared ultra-wideband absorber obtained in Example 1, where 1 is the substrate, 12 is the aluminum thin film reflection layer, 13 is the first tungsten oxide layer, 14 is the second tungsten oxide layer, 15 is the third tungsten oxide layer, 16 is the fourth tungsten oxide layer, 17 is the fifth tungsten oxide layer, 18 is the sixth tungsten oxide layer, and 19 is the seventh tungsten oxide layer;

[0024] Figure 3 Test result diagram of the refractive index and extinction coefficient of the functional layer obtained in Example 1;

[0025] Figure 4 Test diagram of the theoretical and actual absorption effects of the deep ultraviolet-visible-near infrared ultra-wideband absorber obtained in Example 1;

[0026] Figure 5 Test diagram of the absorption effects of the deep ultraviolet-visible-near infrared ultra-wideband absorber obtained in Example 1 at S polarization and P polarization, and at 6° - 70°;

[0027] Figure 6 Test diagram of the actual absorption effects of the deep ultraviolet-visible-near infrared ultra-wideband absorbers obtained in Examples 2 - 4. Detailed implementation manners

[0028] The present invention provides a deep ultraviolet-visible-near infrared ultra-wideband band absorber, including a substrate, a metal thin film reflection layer, and a functional layer that are stacked in sequence from bottom to top;

[0029] The functional layer includes multiple dielectric absorption layers with decreasing complex refractive indices from bottom to top.

[0030] The schematic structural diagram of the deep ultraviolet-visible-near infrared ultra-wideband band absorber obtained by the present invention is as Figure 1 described, where 1 is the substrate, 2 is the metal thin film reflection layer, and 3 is the functional layer.

[0031] The present invention has no special limitations on the type and size of the substrate, and those well-known to those skilled in the art can be used.

[0032] In the present invention, the material of the metal thin film reflection layer preferably includes one or several of Ti, Al, Ni, Au, and Ag. In the present invention, the thickness of the metal thin film reflection layer is preferably greater than 50 nm.

[0033] In the present invention, the material of the functional layer preferably includes tungsten oxide. In the present invention, the functional layer includes a multi-layer dielectric absorption layer with decreasing complex refractive index from bottom to top. The present invention has no specific limitation on the number of layers of the multi-layer dielectric absorption layer, and it can be specifically selected according to actual situations.

[0034] In the present invention, each layer of the dielectric absorption layer preferably satisfies the following three conditions simultaneously: the refractive index under ultraviolet light is 1.8 - 2.63, the extinction coefficient is 0.06 - 1.22, and the wavelength range of the ultraviolet light is 193 - 400 nm; the refractive index under visible light is 2.04 - 2.78, the extinction coefficient is 0.06 - 0.78, and the wavelength range of the visible light is 400 - 800 nm; the refractive index under near-infrared light is 2.05 - 3.25, the extinction coefficient is 0.2 - 0.81, and the wavelength range of the near-infrared light is 800 - 1690 nm. In the present invention, the value of the complex refractive index is the sum of the refractive index and the extinction coefficient.

[0035] In the present invention, the total thickness of the multi-layer dielectric absorption layer is preferably 90 - 200 nm. In the present invention, the thickness of each layer of the dielectric absorption layer is preferably 8 - 50 nm.

[0036] In the present invention, the absorption band range of the deep ultraviolet-visible-near infrared ultra-wideband absorber is preferably 190 - 1700 nm.

[0037] The present invention also provides a preparation method of the deep ultraviolet-visible-near infrared ultra-wideband absorber according to the above technical solution, including the following steps:

[0038] A metal thin film reflection layer and a functional layer are sequentially prepared on the surface of the substrate.

[0039] Before the preparation, the present invention also preferably includes cleaning the substrate.

[0040] In the present invention, without special instructions, all preparation raw materials are commercially available products well-known to those skilled in the art.

[0041] In the present invention, the preparation method of the metal thin film reflection layer is preferably electron beam evaporation deposition. The present invention has no special limitation on the process of the electron beam evaporation deposition, and those well-known to those skilled in the art can be adopted. In the present invention, the preparation method of the functional layer is preferably magnetron sputtering. The present invention has no special limitation on the process of the magnetron sputtering, and those well-known to those skilled in the art can be adopted.

[0042] To further illustrate the present invention, the following describes in detail a deep ultraviolet-visible-near infrared ultra-wideband absorber and its preparation method provided by the present invention with reference to the drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0043] Example 1

[0044] According to Figure 2 the shown structure, prepare a deep ultraviolet-visible-near infrared ultra-wideband band absorber;

[0045] Use a silicon wafer as the substrate, and deposit a 100-nm aluminum thin film reflective layer 12 on the cleaned silicon wafer by electron beam evaporation;

[0046] Put the deposited substrate into a magnetron sputtering device, and sputter multiple tungsten oxide layers in sequence. The thicknesses of the first tungsten oxide layer 13, the second tungsten oxide layer 14, the third tungsten oxide layer 15, the fourth tungsten oxide layer 16, the fifth tungsten oxide layer 17, the sixth tungsten oxide layer 18, and the seventh tungsten oxide layer 19 from bottom to top are 29 nm, 25 nm, 11 nm, 13 nm, 15 nm, 16 nm, and 20 nm respectively, and the total thickness is 129 nm, thus obtaining the deep ultraviolet-visible-near infrared ultra-wideband band absorber.

[0047] Example 2

[0048] Prepare a deep ultraviolet-visible-near infrared ultra-wideband band absorber in the same way as in Example 1;

[0049] Among them, the thicknesses of each tungsten oxide layer from bottom to top are 50 nm, 50 nm, 30 nm, 22 nm, 8 nm, and 40 nm respectively, and the total thickness is 200 nm.

[0050] Example 3

[0051] Prepare a deep ultraviolet-visible-near infrared ultra-wideband band absorber in the same way as in Example 1;

[0052] Replace the aluminum thin film reflective layer with a titanium thin film reflective layer;

[0053] The thicknesses of each tungsten oxide layer from bottom to top are 25 nm, 22 nm, 10 nm, 11 nm, 13 nm, 17 nm, and 25 nm respectively, and the total thickness is 123 nm.

[0054] Example 4

[0055] Prepare a deep ultraviolet-visible-near infrared ultra-wideband band absorber in the same way as in Example 1;

[0056] Replace the aluminum thin film reflective layer with a titanium thin film reflective layer;

[0057] The thicknesses of each tungsten oxide layer from bottom to top are 30 nm, 30 nm, 10 nm, 10 nm, and 10 nm respectively, and the total thickness is 90 nm.

[0058] Performance Test

[0059] Figure 3 It is a test result graph of the refractive index and extinction coefficient of the functional layer obtained in Example 1. The specific results are shown in Table 1;

[0060] Table 1 Test results of the refractive index and extinction coefficient of the functional layer obtained in Example 1

[0061]

[0062]

[0063]

[0064] It can be seen from Table 1 that in the ultraviolet range band (193 nm - 400 nm), the effect of the gradient complex refractive index is not obvious, while in the visible - near infrared range band (400 nm - 1690 nm), the gradient refractive index effect is obvious. The refractive index with the smallest change is at a wavelength of 294 nm, and the refractive index change range is 2.56437 - 2.61654. The extinction coefficient with the smallest change is at a wavelength of 245 nm, and the extinction coefficient change range is 0.90255 - 1.06397. The refractive index with the largest change is at a wavelength of 1690 nm, and the refractive index change range is 2.3138 - 3.24053. The extinction coefficient with the largest change is at a wavelength of 454 nm, and the extinction coefficient change range is 0.07389 - 0.72811.

[0065] Figure 4 It is a comparison graph of the theoretical and actual absorption effects of the band absorber obtained in Example 1. From Figure 4 it can be seen that after comparing the absorption effect with the calculation result, it is found that the calculation result is basically in line with the experimental result. It can be seen from the test curve that the absorber provided by the present invention has a range of 190 - 1700 nm for deep ultraviolet - visible - near infrared ultra - wide band light, and the average absorption effect reaches 88.8%, and the effect in the highest absorption region reaches 99.5%. In the visible - near infrared band of 400 - 1600 nm, the average absorption reaches 91.1%.

[0066] Figure 5 It is a test graph of the absorption effect of the band absorber obtained in Example 1 at S - polarization and P - polarization, and at 6° - 70°. From Figure 5 it can be seen that after the variable - angle test, the absorber is insensitive to the angle, and still has a high absorption at 70°, as well as the polarization - insensitive effect.

[0067] Figure 6 They are the actual absorption effect values of the band absorbers obtained in Examples 2 - 4. The average absorption rates are shown in Table 2;

[0068] Table 2 Average absorption rates of the absorbers obtained in Examples 2 - 4

[0069]

[0070] As can be seen from Table 2, when using different metal reflective layers, the thickness of each functional layer is within 8 - 50 nm, and the total thickness of the functional layers is within 90 - 200 nm. The average absorption effect can reach over 85%.

[0071] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, rather than all of them. Other embodiments can be obtained based on these embodiments without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A deep ultraviolet-visible-near infrared ultra-wideband band absorber, characterized in that, It includes a substrate, a metal thin film reflective layer, and a functional layer that are sequentially stacked from bottom to top; The functional layer includes multiple dielectric absorption layers with sequentially decreasing complex refractive indices from bottom to top; Each dielectric absorption layer simultaneously satisfies the following three conditions: The refractive index under ultraviolet light is 1.8 - 2.63, and the extinction coefficient is 0.06 - 1.

22. The wavelength range of the ultraviolet light is 193 - 400 nm; the refractive index under visible light is 2.04 - 2.78, and the extinction coefficient is 0.06 - 0.

78. The wavelength range of the visible light is 400 - 800 nm; the refractive index under near-infrared light is 2.05 - 3.25, and the extinction coefficient is 0.2 - 0.

81. The wavelength range of the near-infrared light is 800 - 1690 nm.

2. The deep ultraviolet-visible-near infrared ultra-wideband band absorber according to claim 1, characterized in that, The material of the metal thin film reflective layer includes one or more of Ti, Al, Ni, Au, and Ag.

3. The deep ultraviolet-visible-near infrared ultra-wideband band absorber according to claim 1, wherein The thickness of the metal thin film reflective layer is greater than 50 nm.

4. The deep ultraviolet-visible-near infrared ultra-wideband band absorber according to claim 1, characterized in that, The material of the functional layer includes tungsten oxide.

5. The deep ultraviolet-visible-near infrared ultra-wideband band absorber according to claim 1, characterized in that, The total thickness of the multiple dielectric absorption layers is 90 - 200 nm.

6. The deep ultraviolet-visible-near infrared ultra-wideband band absorber according to claim 1, characterized in that, The thickness of each dielectric absorption layer is 8 - 50 nm.

7. The deep ultraviolet-visible-near infrared ultra-wideband band absorber according to claim 1, characterized in that, The absorption band range of the deep ultraviolet - visible - near infrared ultra-wideband absorber is 190 - 1700 nm.

8. The preparation method of the deep ultraviolet-visible-near infrared ultra-wideband band absorber according to any one of claims 1 to 7, characterized in that, It includes the following steps: A metal thin film reflective layer and a functional layer are sequentially prepared on the surface of the substrate.

9. The preparation method according to claim 8, wherein, The preparation method of the metal thin film reflective layer is electron beam evaporation deposition; The preparation method of the functional layer is magnetron sputtering.

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