A fully dielectric GMR-type Goos-Hänchen displacement sensing chip

Abstract

The present invention discloses a fully dielectric GMR type Goos-Hänchen displacement sensing chip, which consists of a three-layer structure. The bottom layer is a transparent dielectric substrate, the middle layer is a dielectric thin film, and the upper layer is a periodically arranged metasurface grating array. The material of the dielectric thin film is a dielectric with a high refractive index and low loss. The material of the metasurface grating array is a dielectric with a relatively low refractive index and low loss. For the periodically arranged metasurface grating array, the period of each periodic unit grating is P, and the range is 300-800 nm. The width of the grating is a, and the range is 0.3*P-0.7*P. The thickness of the grating is h, and the range is 0.5-20 nm. The above structural parameters of the grating are adjusted by micro-nano processing technology. The present invention adopts a fully dielectric GMR type metasurface structure, which can greatly enhance the Goos-Hänchen displacement and has the characteristics of high efficiency and high sensitivity.

Description

Technical Field

[0001] The present invention belongs to the field of optical sensing and relates to an all-medium GMR type Gus Hansen displacement sensor chip, which can be applied to the fields of biological sample detection and disease diagnosis. Background Art

[0002] Goos-Hänchen shift (GHS) refers to a spatial translation of reflected light along the direction of light transmission at the intersection of the incident surface and the total reflection interface. It is an optical phenomenon. Goos-Hänchen shift responds sensitively to changes in the dielectric constant of samples on the chip surface. By detecting the Goos-Hänchen shift of reflected light, samples can be detected in real time and efficiently. The expression of Goos-Hänchen shift is: , which is proportional to the partial differential of the reflection phase with respect to the incident angle. Therefore, the more dramatic the change in the reflection phase (the larger the Q value), the larger the Goos-Hansen shift, which is extremely important for improving the sensitivity of the sensor. However, due to the large loss of metal materials, the Q value of the SPR resonance peak is low. The existing Goos-Hansen shift using the metal SPR (surface plasmon resonance) effect is generally in the order of hundreds of microns, and the sensing sensitivity is also low.

[0003] Metasurface refers to a new type of artificial optical material with extraordinary electromagnetic properties, which is composed of periodic or non-periodic sub-wavelength structural units. It provides a new way to artificially manipulate light and electromagnetic waves, and has now become a research hotspot in the fields of ultra-sensitive biochemical sensors and nanophotonics. Metasurfaces have unique electromagnetic properties that conventional media in nature do not have, and can achieve high-Q resonance peaks through reasonable design.

[0004] Guided mode resonance (GMR) refers to the resonance mode generated by coupling between the external electromagnetic field and the leakage mode of the subwavelength grating waveguide. The metasurface grating array is equivalent to a periodically modulated planar waveguide. When an external propagating wave and the guided wave mode supported by the subwavelength grating waveguide meet the wave vector matching, strong coupling will occur, and the coupled energy will be reflected or transmitted through the periodic grating, forming a sharp reflection or transmission resonance peak. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to propose an all-dielectric GMR type Gus Hansen displacement sensor chip, which can achieve ultra-high sensitivity Gus Hansen displacement sensing, which is of great significance to the fields of biological sample detection, disease diagnosis, etc.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A all-dielectric GMR-type Goos-Hänchen displacement sensing chip, the chip consists of a three-layer structure, the bottom layer is a transparent dielectric substrate, the middle layer is a dielectric thin film, and the upper layer is a periodically arranged metasurface grating array;

[0008] The material of the dielectric thin film is a dielectric with a high refractive index and low loss;

[0009] The material of the metasurface grating array is a dielectric with a relatively low refractive index and low loss;

[0010] For the periodically arranged metasurface grating array, the period of each periodic unit grating is P, and the range is 300 - 800 nm; the width of the grating is a, and the range is 0.3*P - 0.7*P; the thickness of the grating is h, and the range is 0.5 - 20 nm.

[0011] The transparent dielectric substrate includes quartz glass and ordinary glass.

[0012] The material of the dielectric thin film is a dielectric with a high refractive index and low loss, including TiO2, Si3N4, and ZnO; the thickness range of the dielectric thin film is 50 - 300 nm.

[0013] The material of the metasurface grating array is a dielectric with a relatively low refractive index and low loss, including single-layer or multi-layer hBN, single-layer or multi-layer WS 2、 Single-layer or multi-layer MoS2, and SiO2.

[0014] For the periodically arranged metasurface grating array, by reducing the thickness h of the grating, the Q value of the resonance peak increases rapidly; when the material of the grating array is a single-layer two-dimensional material, the Q value reaches the maximum.

[0015] For the all-dielectric GMR-type Goos-Hänchen displacement sensing chip, the wavelength of the resonance peak is changed by adjusting the structural parameters of the metasurface grating array, and it is applied to the enhancement of Goos-Hänchen displacement sensing in the wide band from visible light to near-infrared.

[0016] For the all-dielectric GMR-type Goos-Hänchen displacement sensing chip, there is a sudden change in phase at the high-Q resonance peak, and as the thickness of the metasurface grating decreases, the Q value increases and the phase mutation becomes more severe; controlling the incident light wavelength to be constant, highly sensitive Goos-Hänchen displacement sensing is performed by measuring the displacement change of the reflected light.

[0017] For the all-dielectric GMR-type Goos-Hänchen displacement sensing chip, it is used to localize the light field on the chip surface, improving the surface sensitivity.

[0018] For the all-dielectric GMR-type Goos-Hänchen displacement sensing chip, the structural parameters of the grating are adjusted by micro-nano processing technology.

[0019] Technical effects produced by the present invention:

[0020] Based on the ultra-high Q-value resonance peak of the GMR mode in the metasurface grating array, and having a phase with a sharp mutation at the same time, the present invention can be applied to ultra-sensitive refractive index phase sensing. The extremely strong confinement ability of the periodic nanostructure array to the optical field can greatly enhance the local electric field and enhance the detection ability for ultra-low concentration molecules. High-sensitive refractive index phase sensing can be realized based on this structure, which is of great significance for fields such as biological sample detection and disease diagnosis. Description of the drawings

[0021] Figure 1 It is a schematic structural diagram of a all-dielectric GMR-type Goos-Hänchen displacement sensing chip of the present invention.

[0022] Figure 2 It is the reflection spectrum of the all-dielectric GMR-type Goos-Hänchen displacement sensing chip.

[0023] Figure 3 It is the enhancement of the local electric field at the resonance peak.

[0024] Figure 4 It is a graph showing the relationship between the Q value of the all-dielectric GMR-type Goos-Hänchen displacement sensing chip and the number of hBN layers.

[0025] Figure 5 It is a phase change diagram of the reflected light of the high-Q value resonance peak.

[0026] Figure 6 It is a curve showing the change of the Goos-Hänchen displacement with the refractive index of the surrounding environment.

[0027] Description of reference numerals: 1 - transparent dielectric substrate, 2 - dielectric thin film, 3 - metasurface grating array. Detailed implementation manners

[0028] The present invention will be further described below with reference to the drawings.

[0029] As Figure 1 shown, an all-dielectric GMR-type Goos-Hänchen displacement sensing chip is composed of three layers. The bottom layer is a transparent dielectric substrate 1, the middle layer is a dielectric thin film 2, and the upper layer is a periodically arranged metasurface grating array 3.

[0030] The described transparent dielectric substrate 1 includes quartz glass and ordinary glass.

[0031] The material of the dielectric thin film 2 is a dielectric with a high refractive index and low loss, such as TiO2, Si3N4, and ZnO, etc.; the thickness range of the dielectric thin film 2 is 50 - 300 nm. The refractive indices of these materials in the visible and near-infrared bands are greater than 2.0, and the loss can be ignored.

[0032] The material of the metasurface grating array 3 described above is a dielectric with a relatively low refractive index and low loss, such as two-dimensional materials (single-layer / multilayer hBN, single-layer / multilayer WS2, and single-layer / multilayer MoS2) and SiO2. The refractive indices of these materials in the visible and near-infrared bands are between 1.5 and 2.0, and the loss can be ignored.

[0033] For the periodically arranged metasurface grating array 3, the period of each periodic unit grating is P, ranging from 300 to 800 nm; the width of the grating is a, ranging from 0.3*P to 0.7*P; the thickness of the grating is h, ranging from 0.5 to 20 nm; the above structural parameters of the grating can be adjusted by micro-nano processing technology.

[0034] The material of the metasurface grating array 3 described above is a dielectric with a relatively low refractive index and low loss, including single-layer or multilayer hBN, single-layer or multilayer WS 2、 Single-layer or multilayer MoS2, and SiO2.

[0035] For the periodically arranged metasurface grating array 3, by reducing the thickness h of the grating, the Q value of the resonance peak increases rapidly; when the material of the grating array is a single-layer two-dimensional material, the Q value reaches the maximum.

[0036] For a all-dielectric GMR-type Goos-Hänchen shift sensing chip, the wavelength of the resonance peak is changed by adjusting the structural parameters of the metasurface grating array 3, which is applied to enhance the Goos-Hänchen shift sensing in the wide band from visible light to near-infrared.

[0037] For a all-dielectric GMR-type Goos-Hänchen shift sensing chip, there is a sudden change in phase at the high-Q resonance peak, and as the thickness of the metasurface grating 3 decreases, the Q value increases and the phase mutation becomes more intense; keeping the incident light wavelength unchanged, high-sensitivity Goos-Hänchen shift sensing is performed by measuring the displacement change of the reflected light.

[0038] For a all-dielectric GMR-type Goos-Hänchen shift sensing chip, it is used to localize the light field on the chip surface, improving the surface sensitivity.

[0039] Example 1

[0040] For an all-dielectric GMR-type Goos-Hänchen shift sensing chip, the parameters of the metasurface grating array 3 can be selected as a = 180 nm, h = 0.42 nm, P = 360 nm, and the corresponding material is selected as single-layer hBN. The thickness of the dielectric thin film 2 is 260 nm, and the corresponding material is selected as TiO2. Attached Figure 2It is the reflection spectrum of a all-dielectric GMR-type Goos-Hänchen displacement sensing chip. There is an ultra-high Q-value resonance peak, and the resonance wavelength has been tuned to the visible light band, which can be used for the detection of surface sample concentration, and the resonance wavelength can also be adjusted according to different Raman probe molecules to achieve Raman enhancement. Attached Figure 3 It is the electric field template diagram at the resonance peak of the reflection spectrum. The electric field enhancement is up to 1000 times, and the electric field mode spot is relatively large, with a high enhancement efficiency and high surface sensitivity, which is very suitable for the sensing of surface sample substances and Raman enhancement.

[0041] Example 2

[0042] An all-dielectric GMR-type Goos-Hänchen displacement sensing chip. By reducing the number of layers of the metasurface grating material hBN, the Q value of the resonance peak becomes larger and larger. Attached Figure 4 It is the Q-value change of the all-dielectric GMR-type Goos-Hänchen displacement sensing chip. It can be seen that when the number of hBN layers changes from 20 to 1, the Q value of the resonance peak becomes higher and higher.

[0043] Example 3

[0044] An all-dielectric GMR-type Goos-Hänchen displacement sensing chip. At the high-Q resonance peak caused by the metasurface grating array 3, the reflected light has a violently abrupt phase, so it can be used for ultrasensitive Goos-Hänchen displacement sensing. Attached Figure 5 It is the phase diagram of the violently abrupt change of the reflected light at the high-Q resonance peak.

[0045] Example 4

[0046] An all-dielectric GMR-type Goos-Hänchen displacement sensing chip. There is a violently abrupt phase at the resonance peak, so it can be used for Goos-Hänchen displacement sensing. When the concentration of the sample to be detected on the chip surface changes, the corresponding refractive index will also change, and then the Goos-Hänchen displacement will change. Attached Figure 6 It is the curve of the Goos-Hänchen displacement changing with the refractive index of the chip surrounding environment. When the wavelength of the incident light is controlled to be constant, the Goos-Hänchen displacement of the reflected light will change. When the refractive index changes from 1.330 to 1.330001, the Goos-Hänchen displacement changes from 106842 μm to 17114 μm, and the sensitivity S is 9.07*10 10 μm / RIU, so it can be used for ultrasensitive Goos-Hänchen displacement phase sensing.

[0047] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A fully dielectric GMR-type Goos-Hänchen displacement sensing chip, characterized in that, The chip consists of a three-layer structure. The bottom layer is a transparent dielectric substrate (1), the middle layer is a dielectric thin film (2), and the upper layer is a periodically arranged metasurface grating array (3). The material of the dielectric thin film (2) is a dielectric with a high refractive index and low loss, including TiO2, Si3N4, and ZnO. The thickness range of the dielectric thin film (2) is 50 - 300 nm. The material of the metasurface grating array (3) described above is a dielectric with a relatively low refractive index and low loss, including single or multiple layers of hBN, single or multiple layers of WS 2、 single or multiple layers of MoS2, and SiO2; For the periodically arranged metasurface grating array (3), the period of each periodic unit grating is P, with a range of 300 - 800 nm; the width of the grating is a, with a range of 0.3*P - 0.7*P; the thickness of the grating is h, with a range of 0.5 - 20 nm.

2. The all-dielectric GMR type Goos-Hänchen displacement sensing chip according to claim 1, characterized in that, The transparent dielectric substrate (1) includes quartz glass and ordinary glass.

3. The all-dielectric GMR type Goos-Hänchen displacement sensing chip according to claim 1, characterized in that, For the periodically arranged metasurface grating array (3), by reducing the thickness h of the grating, the Q value of the resonance peak increases rapidly; when the material of the grating array is a single-layer two-dimensional material, the Q value reaches the maximum.

4. A fully dielectric GMR type Goos-Hänchen displacement sensing chip according to claim 1, characterized in that, The wavelength of the resonance peak is changed by adjusting the structural parameters of the metasurface grating array (3), which is applied to enhance the Goos-Hänchen shift sensing in the wide wavelength range from visible light to near-infrared.

5. A all-dielectric GMR-type Goos-Hänchen displacement sensing chip according to claim 1, characterized in that, There is a sudden change in phase at the high-Q resonance peak, and as the thickness of the metasurface grating (3) decreases, the Q value increases and the phase mutation becomes more intense. Keeping the incident light wavelength unchanged, highly sensitive Goos-Hänchen shift sensing is carried out by measuring the displacement change of the reflected light.

6. A all-dielectric GMR type Goos-Hänchen displacement sensing chip according to claim 1, characterized in that, The described chip is used to localize the light field on the chip surface, improving the surface sensitivity.

7. A fully dielectric GMR type Goos-Hänchen displacement sensing chip according to claim 1, characterized in that, The structural parameters of the grating are adjusted by micro-nano processing technology.

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