A high-sensitivity Goos-Hanhen shift gas sensor based on subwavelength hyperbolic material and a preparation method thereof
Patent Information
- Application Number
- CN202210944003.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-08-05
- Publication Date
- 2025-10-17
- Estimated Expiration
- 2042-08-05
Smart Images
Figure CN115575352B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of optical science and technology, and particularly relates to a high-sensitivity Goos-Haunche displacement gas sensor based on subwavelength hyperbolic material and a preparation method thereof. BACKGROUND
[0002] Optical sensors have a wide application prospect in many fields such as clinical diagnosis, environmental monitoring and biomedicine. The optical sensors have advantages such as anti-electromagnetic interference, multi-channel detection, remote sensing, high sensitivity, no label and real-time monitoring, and are widely studied. The sensitivity of common optical gas sensors is low, and the common optical gas sensors cannot be used for accurate real-time diagnosis and monitoring. The Goos-Haunche displacement has been a research hotspot since it was discovered. People have been committed to studying how to obtain a larger displacement. With the discovery of various materials, the characteristics of the displacement have been discovered in turn. Some people have found that there is also a displacement in the photonic band gap, and have given a theoretical explanation, and a negative displacement has been found in a two-dimensional photonic crystal. With the discovery of metamaterials, the characteristics of the displacement on the surface of the metamaterials have been widely studied. In order to obtain a larger displacement and meet the demand of high sensitivity of optical gas sensors, a preparation method of a high-sensitivity displacement gas sensor based on subwavelength hyperbolic metamaterials is proposed. SUMMARY
[0003] In view of the deficiencies in the prior art of common optical gas sensors, the primary purpose of the application is to provide a high-sensitivity displacement gas sensor based on subwavelength hyperbolic material.
[0004] Another purpose of the application is to provide a preparation method of a high-sensitivity displacement gas sensor based on subwavelength hyperbolic material.
[0005] In order to achieve the above-mentioned purposes, the application adopts the following technical solutions:
[0006] A high-sensitivity displacement gas sensor based on subwavelength hyperbolic metamaterials, the hyperbolic metamaterials are composed of alternating layers of metal silver and dielectric titanium dioxide, the background medium of the incident region is helium, and the background medium of the exit region is air.
[0007] In the above technical solution, the thickness of the metal silver in the hyperbolic metamaterials is d Ag = 42 nm.
[0008] In the technical solution, the thickness of the dielectric titanium dioxide in the hyperbolic metamaterial is
[0009] In the technical solution, the refractive index of the background medium helium in the incident area is n He = 1.000032.
[0010] In the technical solution, the refractive index of the background medium air in the exit area is n air = 1.000265.
[0011] A high-sensitivity displacement gas sensor based on a sub-wavelength hyperbolic metamaterial The preparation method of the displacement gas sensor comprises the following steps:
[0012] Step one: design a gas sensor based on TM wave;
[0013] Step two: explore the displacement characteristics of the incident angle, incident wavelength, background dielectric constant and filling factor;
[0014] Step three: based on the displacement characteristics obtained in step two, select the incident angle θ = 69.25 deg, the incident wavelength λ = 342 nm and the filling factor f = 0.28 to obtain the maximum displacement;
[0015] Step four: based on the incident condition in step three, and filling helium in the incident area, a gas sensor with a sensitivity of S = 1.59 x 10 9 nm / RIU can be obtained.
[0016] Principle of the application: according to the Drude model, the dielectric constant of metal silver and dielectric can be calculated; based on the effective dielectric constant, the dielectric constant expression of the hyperbolic metamaterial in the vertical and parallel directions can be calculated; according to the Fresnel formula, the reflection coefficient expression of the transverse electromagnetic wave can be obtained; based on the above theory and the steady-state phase method, the displacement expression can be obtained The displacement expression provides a theoretical basis for preparing a high-sensitivity displacement gas sensor based on a sub-wavelength hyperbolic metamaterial.
[0017] Advantages and effects of the application:
[0018] 1. The hyperbolic metamaterial structure composed of metal and dielectric alternately combined in the application not only improves the sensitivity of the optical gas sensor, but also has the advantages of relatively easy processing, wideband non-resonance, three-dimensional block response and flexible wavelength tuning.
[0019] 2. The present invention changes the direction of the incident wavelength directly by adjusting the incident wavelength. At the same time, by limiting the critical wavelength, filling factor and background dielectric constant and combining The intensity and direction characteristics of the displacement are studied. By filling the background medium in the incident area with helium, a sensitivity of up to 1.59×10 9 nm / RIU gas sensor for easy detection of air quality. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 High sensitivity for subwavelength hyperbolic metamaterials Schematic diagram of the displacement gas sensor;
[0021] Figure 2 Subwavelength structures at different incident wavelengths Graph of displacement versus incident angle;
[0022] Figure 3 The maximum value on the subwavelength hyperbolic metamaterial surface Graph showing the displacement versus incident wavelength;
[0023] Figure 4 The filling factor f and the background dielectric constant ε of the subwavelength hyperbolic metamaterial Displacement influence curve diagram;
[0024] Figure 5 For different gases Displacement graph. DETAILED DESCRIPTION
[0025] The present invention will be described in further detail below with reference to the accompanying drawings.
[0026] Figure 1 High sensitivity for subwavelength hyperbolic metamaterials Diagram of the displacement gas sensor structure. The hyperbolic metamaterial in the structure diagram is composed of an alternating combination of metallic silver and dielectric titanium dioxide. The background at the input is helium, and the background at the output is air.
[0027] In the hyperbolic metamaterial, the thickness of the metallic silver is d Ag =42nm, the thickness of dielectric titanium dioxide is A beam of TM wave with an incident wavelength of λ = 342nm and an incident angle of θ = 69.25deg is incident on the hyperbolic metamaterial surface with a background of helium, and high sensitivity can be obtained. Preparation of displacement gas sensor.
[0028] Figure 2 a is the incident wavelength λ = 360nm, the filling factor is f = 1, that is, there is only titanium dioxide material in the structure, which can obtain the maximum The displacement is -0.19μm.
[0029] Figure 2 (b) is the incident wavelength λ = 360nm, the filling factor is f = 0.28, the structure is composed of metallic silver and titanium dioxide alternately, which can obtain the maximum The displacement is -43.20 μm. In this embodiment, the incident wavelength is between 300 nm and 375 nm, which is a type I hyperbolic metamaterial.
[0030] Figure 2 (c) The incident wavelength is λ = 500nm, the filling factor is f = 0.28, and the structure is the same as the hyperbolic metamaterial. The maximum The displacement is -2.19μm.
[0031] Figure 2 (d) is the case where the incident wavelength is λ = 750nm, the filling factor is f = 0.28, and the structure is the same as the hyperbolic metamaterial, which can obtain the maximum The displacement is -0.45μm.
[0032] Depend on Figure 2 It can be seen that type I hyperbolic metamaterials meet the high sensitivity requirements of optical gas sensors.
[0033] Figure 3 is Figure 2 (b) Based on the above, the effect of incident wavelength on The effect of displacement can be seen in the incident wavelength range of 310nm to 370nm The displacement increases first and then decreases, and the offset direction changes from positive to negative. There is a critical wavelength (about 340nm) between the displacements. When the incident wavelength is less than the critical wavelength, The displacement is positive, and vice versa. In addition, the closer the incident wavelength is to the critical wavelength, The greater the displacement, the better the metal layer thickness is. The optimal metal layer thickness is determined by the relationship between the internal loss and the radiation loss in the resonant mode. When the internal loss is greater (less) than the radiation loss, The displacement is negative (positive), the smaller the difference between the two, The greater the displacement. Figure 3 Choose the best for us Provides ideas.
[0034] Figure 4 It can be seen that the filling factor f and the background dielectric constant ε Displacement has an impact. Figure 4 In (a), the incident wavelength is less than the critical wavelength, and it can be found that the positive The displacement increases with the fill factor, and the negative The displacement decreases with the increase of f. In Figure 4 (b), the incident wavelength is larger than the critical wavelength, and the negative displacement can be observed. The displacement decreases with the increase of the filling factor. We know that the filling factor indirectly affects the hyperbolic metamaterial permittivity by affecting the displacement.
[0035] In Figure 4 (c) and Figure 4 (d), the incident wavelength λ = 320 nm is smaller than the critical wavelength, and the positive displacement can be observed. The negative displacement decreases with the increase of the background permittivity ε.
[0036] That is, increasing the filling factor and the background permittivity is equivalent to blue-shifting the critical wavelength. Therefore, when the incident wavelength is smaller than the critical wavelength, the displacement direction changes. When the incident wavelength is larger than the critical wavelength, the displacement direction does not change. This provides a theoretical basis for us to prepare optical gas sensors.
[0037] Example 1: Preparation of a high-sensitivity gas sensor based on displacement
[0038] Based on the above implementation, by observing the change of the displacement under the same incident wavelength and incident angle, the composition of the gas can be inferred. The change of the composition of the gas will cause a slight change in its refractive index, thereby causing a change in the displacement.
[0039] A method for preparing a high-sensitivity displacement gas sensor based on subwavelength hyperbolic metamaterials, comprising the following steps:
[0040] Step 1: Design a gas sensor based on TM waves;
[0041] Step 2: Explore the enhancement characteristics of the displacement in the incident angle, incident wavelength, background permittivity, and filling factor;
[0042] Step 3: Based on the characteristics of the displacement obtained in Step 2, select the incident angle θ = 69.25 deg, the incident wavelength λ = 342 nm, and the filling factor f = 0.28 conditions that can obtain the maximum displacement;
[0043] displacement.Step four: based on the condition of step three, the sensitivity of the gas sensor can reach S=1.59×10 9 nm / RIU by filling helium in the incident region.
[0044] Figure 5 In the embodiment, the wavelength of incident light is selected as λ=342nm, the filling factor is selected as f=0.28, and the incident angle is selected as θ=69.25deg to perform theoretical calculation on the prepared optical gas sensor. In the embodiment, helium is selected to prepare the optical gas sensor.
[0045] In the embodiment, the refractive index of helium is n He =1.000032, and the refractive index of air is n air =1.000265. The helium is filled into the incident region of the hyperbolic metamaterial.
[0046] In the embodiment, the optical gas sensor with a sensitivity of S=1.59×10 9 nm / RIU can be prepared.
[0047] The above embodiment is a preferred embodiment of the present application, and any change, modification, substitution, combination, which does not deviate from the spirit and principle of the present application, should be an equivalent replacement, and all should be included in the protection scope of the present application.
Claims
1. A high-sensitivity method based on subwavelength hyperbolic metamaterials Displacement gas sensor, characterized by: The hyperbolic metamaterial is composed of alternating layers of metallic silver and dielectric titanium dioxide, with helium as the background medium in the incident region and air as the background medium in the exit region. The thickness of the metallic silver in the hyperbolic metamaterial is d Ag =42nm; The thickness of the dielectric titanium dioxide in the hyperbolic metamaterial is The refractive index of the incident area background medium helium is n He =1.000032; The refractive index of the background medium air in the emission area is n air =1.000265.
2. A high sensitivity based on subwavelength hyperbolic metamaterial according to claim 1 The method for preparing a displacement gas sensor is characterized in that: The steps include: Step 1: The gas sensor is designed based on TM waves; Step 2: Explore Enhanced characteristics of displacement with respect to incident angle, incident wavelength, background dielectric constant, and fill factor; Step 3: Based on the results from step 2 The displacement characteristics were selected to obtain the maximum displacement at an incident angle of θ = 69.25 degrees, an incident wavelength of λ = 342 nm, and a fill factor of f = 0.
28. Step 4: Based on the conditions of step 3, the incident area is filled with helium to obtain a sensitivity of S = 1.59 × 10 9 nm / RIU gas sensor.