Narrowband metasurface infrared detector based on mirror image coupling medium BIC and manufacturing method thereof

Abstract

The invention discloses a narrow-band metasurface infrared detector based on a mirror image coupling medium BIC and a manufacturing method of the narrow-band metasurface infrared detector, and belongs to the technical field of crossing of infrared detection and metamaterials. The infrared detector comprises a medium metasurface functional layer, a medium film layer, an upper electrode metal layer, a pyroelectric functional layer and a lower electrode metal layer which are sequentially arranged from top to bottom; the upper electrode metal layer and the lower electrode metal layer are respectively and electrically connected with a test circuit, the dielectric metasurface function layer comprises a plurality of metasurface micro-nano, the metasurface micro-nano is periodically arranged to form an array form, and a mirror image coupling type BIC mode is excited. The device has the advantages of narrow-band response, high absorption, insensitivity to the polarization state of incident light, capability of widening the processing tolerance and flexible tuning of multiple parameters.

Description

Technical Field

[0001] The present invention relates to a narrow-band metasurface infrared detector based on a mirror-coupled medium (BIC) and a manufacturing method thereof, and belongs to the technical field of intersection of infrared detection and metamaterials. Background Art

[0002] In the field of infrared detection technology, efficient and sensitive detectors are core components in key areas such as gas analysis, biomedical imaging, and security monitoring. While traditional infrared detection devices (such as pyroelectric detectors, microbolometers, and quantum well infrared detectors) are technologically mature and cover a wide range of wavelengths, they generally face bottlenecks such as bulk, high cost, and limited functionality. For example, multi-gas detection relies on multiple "filter + detector" combinations, resulting in complex and costly system integration. Furthermore, the spectral selectivity of external filters is limited, making fast and accurate multi-parameter analysis difficult. Furthermore, the sensitivity of traditional devices, especially their spectral resolution (full width at half maximum of approximately hundreds of nanometers), is no longer sufficient to meet modern precision detection requirements, such as environmental trace gas monitoring or biomolecular fingerprinting.

[0003] In recent years, metasurface infrared detectors have developed rapidly. By manipulating light fields through subwavelength structures, they demonstrate disruptive potential in miniaturization, high sensitivity, and multimodal detection. These detectors offer the following advantages: 1) integrated filtering and detection capabilities of metallic metasurface plasmon resonances; 2) high-Q resonances of bound states in the continuum (BIC) of dielectric metasurfaces; and 3) the CMOS compatibility and low loss advantages of dielectric metasurfaces. However, existing metasurface infrared detectors suffer from the following drawbacks:

[0004] 1) Inherent defects of metal-based MIM structures: Metal nanostructures (such as gold and silver) that surface plasmon resonance (SPR) relies on have high ohmic losses; micro-nano processing requires stringent precision and high process complexity (electron beam lithography + metal lift-off), making it difficult to be compatible with large-scale integration; and low spectral resolution (full width at half maximum FWHM > 200 nm), which cannot meet the requirements of molecular fingerprint-level narrowband detection (for example, the width of the characteristic absorption peak of a gas is usually < 50 nm).

[0005] 2) Application limitations of mirror-coupled dielectric BIC metasurfaces: Traditional symmetric protected BICs are extremely sensitive to geometric parameters, have insufficient processing tolerances, and rely on specific incident polarization (such as x- or y-polarized light), which limits the adaptability of light fields in actual scenarios; multi-band tuning requires complex layered structure design, and it is difficult to achieve wide spectral coverage through single-layer parameters.

[0006] 3) Integration challenges of thermal detection units: Multiple sets of independent “metasurface + detector” arrays are required for multi-gas detection. The lack of a polarization-independent confocal detection mechanism makes it difficult to compress the system to a miniaturized size (e.g., chip level).

[0007] 4) The contradiction between polarization sensitivity and broad-spectrum adaptability: Existing metasurface detectors are generally sensitive to the polarization state of the incident light (for example, plasma resonance only supports a specific polarization direction). However, in actual applications, the polarization state of infrared radiation is complex and changeable, requiring additional polarization filtering components, further increasing the complexity of the system. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the defects of the existing technology and provide a narrow-band metasurface infrared detector based on a mirror-coupled medium BIC and a manufacturing method thereof, which has the advantages of narrow-band response and high absorption, insensitivity to the polarization state of the incident light, relaxed processing tolerance, and flexible tuning of multiple parameters.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0010] In the first aspect, the present invention provides a narrow-band metasurface infrared detector based on a mirror-coupled dielectric BIC, comprising a dielectric metasurface functional layer, a dielectric film layer, an upper electrode metal layer, a pyroelectric functional layer and a lower electrode metal layer arranged in sequence from top to bottom, wherein the upper electrode metal layer and the lower electrode metal layer are electrically connected to a test circuit, respectively; the dielectric metasurface functional layer comprises a plurality of metasurface micro-nanos, and the metasurface micro-nanos are periodically arranged to form an array form, thereby exciting a mirror-coupled sporadic BIC mode.

[0011] The material of the dielectric metasurface functional layer includes Ge or Si, and the shape of the metasurface micro-nanostructure includes a disk, a cube and an elliptical cylinder.

[0012] The dielectric film layer is made of SiO2, SiC or CaF2, and has a thickness of 50-300 nm.

[0013] The material of the upper electrode metal layer and the lower electrode metal layer includes Au or Ag, and the thickness is 50-100 nm.

[0014] The material of the pyroelectric functional layer includes LiTaO3 or LiNbO3, and the thickness is 200-500 nm.

[0015] The connection methods between the upper electrode metal layer and the lower electrode metal layer and the test circuit include upper and lower contact and side contact. The upper and lower contact is specifically: opening micro-nano through holes on the dielectric film layer to achieve contact between the test circuit and the upper electrode metal layer, and opening through holes on the back side of the substrate to achieve contact between the test circuit and the lower electrode metal layer; the side contact is specifically: leading out the upper and lower electrodes on the sides of the upper electrode metal layer and the lower electrode metal layer and then connecting them to the test circuit.

[0016] In a second aspect, the present invention provides a method for manufacturing a narrow-band metasurface infrared detector based on a mirror-coupled medium BIC, comprising the following steps:

[0017] The pyroelectric film is cleaned and dried, and then surface activated to obtain a pyroelectric functional layer;

[0018] Performing metal electrode evaporation on the upper and lower surfaces of the pyroelectric functional layer to form an upper electrode metal layer and a lower electrode metal layer respectively;

[0019] forming a dielectric film layer on the upper electrode metal layer by chemical vapor deposition;

[0020] On the upper surface of the dielectric film layer, a micro-nano periodic array of the metasurface is prepared through photolithography and deposition processes to form a dielectric metasurface functional layer, which stimulates the mirror-coupled occasional BIC mode.

[0021] The cleaning of the pyroelectric film includes two steps: organic solvent ultrasonic cleaning and deionized water rinsing; the drying adopts nitrogen blowing; and the surface activation adopts plasma enhanced surface activation.

[0022] The photolithography process includes three steps: coating, exposure and development.

[0023] The deposition process adopts magnetron sputtering.

[0024] Beneficial effects of the present invention: The present invention provides a narrow-band metasurface infrared detector based on a mirror-coupled dielectric (BIC) and a method for manufacturing the same. This invention achieves an innovative narrow-band infrared detection architecture through the mirror-coupled dielectric (BIC) metasurface, and has the following advantages:

[0025] 1. Narrowband response and high absorption: Utilizing the dipole mirror-coupled incidental BIC mode of dielectric metasurface units (such as Ge nanodisks), a narrowband response with an absorptivity greater than 99% (full width at half maximum FWHW < 15nm, Q value exceeding 300) is achieved in the target infrared band (such as 3.31μm for CH4, 4.26μm for CO2, etc.). Compared with traditional metal-based MIM structures, the resolution is improved by an order of magnitude, the detection sensitivity is improved, and it is suitable for gas detection.

[0026] 2. Polarization-independent and processing fault-tolerant: using a parametric accident type BIC design (asymmetric protection type), the super surface structure is a disc, etc., which is not sensitive to the polarization state of the incident light, and has more practical value. Compared with the low tolerance of the symmetric protection type processing to the deviation of the structural parameters (nanometer level precision is required), the present application can relax the processing tolerance (such as the absorption efficiency remains > 95% when the nanodisk radius deviation is ±10nm), and is easier to scale up.

[0027] 3. Multi-parameter flexible tuning: only the geometric parameters of the single-layer structure (such as nanodisk radius and height, unit period, dielectric layer thickness, etc.) need to be adjusted to realize wavelength tuning range > 1000nm, covering CO2(4.26μm), CH4(3.31μm) and other typical gas absorption peaks. No complex interlayer structure is needed, and the overall structure is miniaturized. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structure diagram of a narrow-band super surface infrared detector based on mirror coupling medium BIC of the present application, wherein (a) is a system diagram, (b) is an upper electrode metal layer and a lower electrode metal layer and a test circuit between the upper and lower contact connection diagram, (c) is an upper electrode metal layer and a lower electrode metal layer and a test circuit between the side edge contact connection diagram;

[0029] Figure 2 is a methane (CH4) characteristic waveband absorption spectrum diagram in the present application;

[0030] Figure 3 is a super surface light field distribution simulation diagram in the present application;

[0031] Figure 4 is a super surface period regulation spectrum response Q value diagram in the present application;

[0032] Figure 5 is a carbon dioxide (CO2) characteristic waveband absorption spectrum diagram in the present application;

[0033] Figure 6 is a multi-gas detection unit integrated spectrum diagram in the present application. DETAILED DESCRIPTION

[0034] The present application will be further described below in conjunction with the drawings, and the following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0035] As Figure 1As shown, the present invention discloses a narrow-band metasurface infrared detector based on mirror-coupled dielectric BIC, focusing on the needs of high-sensitivity infrared detection, adopting a dielectric-dominated, metal-assisted layered architecture, and precisely controlling the light-heat-electricity conversion process. The detector includes a dielectric metasurface functional layer, a dielectric film layer, an upper electrode metal layer, a pyroelectric functional layer, and a lower electrode metal layer arranged in sequence from top to bottom. The upper electrode metal layer and the lower electrode metal layer are electrically connected to the test circuit respectively. The dielectric metasurface functional layer includes a plurality of metasurface micro-nanos, which are periodically arranged to form an array form, and an occasional BIC mode is achieved through mirror coupling.

[0036] Specifically, the dielectric metasurface functional layer serves as the core light field control unit, and a Ge or Si dielectric metasurface is selected to construct periodically arranged metasurface micro-nano structures such as disks, cubes, elliptical cylinders and other array forms. This embodiment takes Ge disks as an example for subsequent explanation.

[0037] Materials and parameters: Ge material has a high refractive index (n ≈ 4.0-4.5) and low intrinsic loss (absorption coefficient < 10 cm⁻¹) in the mid-infrared band (3-12 μm). The disk radius (r = 400-800 nm), height (h = 500-700 nm), and period (p = 1500-2500 nm) are synergistically controlled by geometric parameters to excite the mirror-coupled medium BIC mode (quasi-bound state in the continuous domain), achieving narrow-band perfect absorption (absorption rate > 99%) in the mid-infrared target bands (such as the CH4 characteristic peak at 3.31 μm and the CO2 characteristic peak at 4.26 μm), with a full width at half maximum of < 15 nm (Q value exceeding 300).

[0038] The design of the present invention belongs to the occasional parameter type BIC, which breaks the polarization limitation of the symmetric protection type BIC, making the structure insensitive to the polarization of the incident light and adapting to the infrared detection needs of complex environments.

[0039] The dielectric film layer (photothermal conduction buffer layer) uses infrared transparent low-loss dielectrics (such as SiO2, SiC, CaF2, thickness (d = 50-300nm)) to achieve the following functions: optical field isolation: blocking the near-field coupling between the upper metasurface and the underlying metal electrode to prevent metal ohmic loss from interfering with the BIC high-Q resonance; processing compatibility: compatible with the micro-nano processing technologies (electron beam lithography, atomic layer deposition) of the metasurface and metal electrodes to ensure the quality of the interlayer interface.

[0040] The top electrode metal layer, made of a high-conductivity, low-thermal-mass metal (such as Au or Ag, with a thickness of 50-100 nm), serves as the top electrode of the pyroelectric layer. Its electrical function is to collect polarized charge generated by the pyroelectric material due to temperature changes. Thermal optimization is to control the heat capacity of the metal layer to prevent excessive absorption of photothermal energy by the metal and maintain the temperature sensitivity of the pyroelectric layer.

[0041] The pyroelectric functional layer is the core energy conversion unit, and high thermoelectric coefficient pyroelectric materials (such as LiTaO3, LiNbO3, thickness D = 200-500nm) are selected:

[0042] Material properties: Using pyroelectric materials with high thermoelectric coefficients, high temperature resolution can be achieved in infrared detection scenarios;

[0043] Structural synergy: By regulating the thermal conductivity of the dielectric film layer, the temperature response of the pyroelectric layer is matched with the light absorption of the metasurface, supporting high-frequency infrared signal detection.

[0044] The lower electrode metal layer and the upper electrode metal layer are designed symmetrically, and the same metal material (thickness t = 50-100nm) can be used to construct a vertical test circuit.

[0045] Electrode layout: supports two contact modes, see Figure 1 (b) and Figure 1 (c).

[0046] Upper and lower contacts: A micro-nano through-hole (diameter 50-200 nm) is opened in the dielectric film layer to achieve contact between the test circuit and the upper electrode, minimizing the obstruction of the light field; a through-hole (diameter = 10-50 μm) is opened on the back of the substrate (such as Si substrate, thickness (300-500 μm)) to connect the lower electrode to the test circuit, compatible with chip-scale packaging.

[0047] Side contact: Upper and lower electrodes are brought out on the side of the device (< 50 μm from the edge), suitable for wafer-level integration testing.

[0048] The present invention also discloses a method for fabricating a narrow-band metasurface infrared detector based on a mirror-coupled dielectric BIC. The method is used to prepare a layered structure (dielectric metasurface / dielectric film / metal electrode / pyroelectric layer / metal electrode) of a mirror-coupled dielectric BIC metasurface infrared detector. The method uses micro-nano processing technology to achieve precise fabrication and integration of each functional layer. The method specifically includes the following steps:

[0049] Step 1: Pyroelectric film pretreatment (core functional layer preparation). The goal is to obtain a clean, surface-activated pyroelectric substrate to ensure subsequent interlayer adhesion and electrical performance.

[0050] a) Cleaning process:

[0051] Select pyroelectric film (LiTaO3 or LiNbO3, thickness 1-5 μm), and pass through:

[0052] Organic solvent ultrasonic cleaning: Immerse the pyroelectric film in anhydrous ethanol (or acetone) and clean it at 40 kHz ultrasonic frequency for 3-5 minutes to remove organic impurities on the surface;

[0053] Deionized water rinse: transfer to a deionized water ultrasonic bath and rinse for 2 minutes to remove residual solvent;

[0054] Nitrogen drying: Use nitrogen with a purity of > 99.99% at a flow rate of 5-10 L / min to avoid electrostatic adsorption of dust (if particles still remain on the surface, use 100-200 mJ / cm² UV-ozone treatment).

[0055] b) Surface activation process:

[0056] Plasma-enhanced surface activation is used, and the equipment is an inductively coupled plasma (ICP) etcher:

[0057] Gas environment: oxygen (O2) flow rate 50-100 sccm, vacuum degree maintained at 1-5 Pa;

[0058] Process parameters: RF power 50-100 W, treatment time 1-3 minutes;

[0059] Function: Through oxygen plasma bombardment, active groups such as hydroxyl (-OH) are introduced to improve the adhesion of subsequent metal electrodes / dielectric films.

[0060] Step 2: Metal electrode evaporation (electrical signal collection layer). The goal is to prepare low-resistance, uniform upper and lower metal electrodes to ensure efficient transmission of thermoelectric signals.

[0061] Equipment: Electron beam evaporation system (e-beam evaporator), equipped with a quartz crystal film thickness monitor.

[0062] Process parameters: gold source purity > 99.9%, heating power controlled at 5-10 kW, evaporation rate 0.5-1 nm / s;

[0063] Deposition thickness: 50-100 nm for both upper and lower electrodes (calibrated in real time by a film thickness monitor);

[0064] Post-processing: After deposition, anneal at 300-400℃ in N2 atmosphere for 10-20 minutes to eliminate internal stress and improve electrode conductivity.

[0065] Step three: dielectric film growth (photothermal conduction buffer layer). The goal is to prepare an infrared-transparent, low-loss dielectric film (such as SiO2) to isolate the near-field coupling between the metasurface and the metal electrode.

[0066] Equipment: Plasma enhanced chemical vapor deposition (PECVD) system.

[0067] Process parameters (taking SiO2 as an example):

[0068] Reactive gases: SiH4 (flow rate 10-20 sccm), N2O (flow rate 100-200 sccm);

[0069] Process conditions: RF power 100-200 W, temperature 200-300°C, deposition pressure 10-30 Pa;

[0070] Film thickness control: Adjust the deposition time to a target thickness of 30-50 nm (online monitoring by ellipsometer).

[0071] Key role: Constructing a photothermal conduction "buffer layer" to match the thermal conductivity difference between the metasurface (Ge) and the pyroelectric layer (LiTaO3 or LiNbO3), and optimizing the light-to-heat conversion efficiency.

[0072] Step 4: Preparation of dielectric metasurface (light field control core layer). Objective: Through photolithography + deposition process, prepare a periodically arranged Ge micro-nanodisk array to stimulate the mirror-coupled BIC mode.

[0073] a) Photolithography patterning:

[0074] Coating: Spin-coat a positive photoresist (e.g., AZ 5214E) at 3000-4000 rpm to obtain a photoresist layer with a thickness of 500-1000 nm.

[0075] Exposure: Electron beam lithography (EBL) or deep ultraviolet lithography (DUV) is used to expose the designed pattern (disk radius 100-500 nm, period 500-1500 nm);

[0076] EBL parameters: accelerating voltage 50-100 kV, electron beam dose 100-300 μC / cm²;

[0077] Development: Use the corresponding developer (such as AZ 300MIF) for 60-120 seconds to obtain a micro-nanodisk photoresist mask.

[0078] b) Ge material deposition:

[0079] Equipment: Magnetron sputtering system or atomic layer deposition (ALD) system;

[0080] Process selection:

[0081] Magnetron sputtering (suitable for large-scale batch production): Ge target purity > 99.99%, sputtering power 100-200W, Ar gas flow 20-40sccm, deposition thickness 200-800nm (matching photoresist mask);

[0082] ALD (suitable for high-precision thickness control): Ge (Et)4 as precursor, deposition temperature 200-300℃, cycle number control thickness, achieve atomic level precision (error <±0.1nm);

[0083] Pattern transfer: through reactive ion etching (RIE), with CF4 / O2 as etching gas, the photoresist mask pattern is transferred to the Ge layer, and a micro-nano disc array is obtained (etching rate 50-100nm / min, anisotropy ratio > 8:1).

[0084] Step five, multi-gas detection function expansion, target: through micro-nano structure array design, realize multi-gas characteristic wave band detection at the same time.

[0085] Pattern design: in the photoresist mask making stage, adopt multi-region array design, such as Figure 6 As shown, two possible paths for the same detector to detect multiple gases at the same time are presented: ① Different absorption peak micro-nano unit combination, covering CH4(3.31μm), CO2(4.26μm) and other characteristic wave bands at the same time, supporting multi-gas synchronous detection; ② Overall unit geometry scaling, expanding the absorption spectrum range, verifying the feasibility of wide-spectrum multi-molecule detection.

[0086] Region 1: micro-nano disc parameter adaptation for CH4 detection (radius 420nm, period 1500nm, corresponding to 3.31μm absorption peak);

[0087] Region 2: micro-nano disc parameter adaptation for CO2 detection (radius 750nm, period 2000nm, corresponding to 4.26μm absorption peak);

[0088] Region division: realized by "regional exposure + development" of photoresist mask, the distance between adjacent regions is > 5μm, avoiding light field crosstalk.

[0089] Process compatibility: multi-region structure can be completed in a single photoetching + deposition process, without additional process steps, ensuring batch production efficiency.

[0090] Step 6: Post-processing and performance testing. Release the structure: remove residual photoresist (using O2 plasma ashing, power 100-200 W, time 5-10 minutes);

[0091] Performance testing:

[0092] Spectral testing: Use a Fourier transform infrared spectrometer (FTIR) to verify the absorption rate of bands such as 3.31 μm (CH4) and 4.26 μm (CO2) (target > 95%);

[0093] Electrical testing: Build a probe station + lock-in amplifier test system to measure the pyroelectric response current;

[0094] Polarization test: Verify polarization insensitivity through polarization controller + infrared light source.

[0095] The working principle of the light-heat-electricity synergistic conversion mechanism of the present invention is as follows:

[0096] The present invention realizes high-sensitivity infrared detection through narrow-band light absorption-pyroelectric conversion driven by a mirror-coupled medium BIC. The process is as follows:

[0097] (1) Light field manipulation and narrowband absorption

[0098] The Ge disk array on the dielectric metasurface excites quasi-bound state resonance in the target infrared band (such as 3.31 μm and 4.26 μm, etc.) through the mirror-coupled BIC mode (the synergistic effect of mirror reflection between the metasurface and the underlying dielectric film / metal electrode), so that the incident light energy is highly localized and absorbed by the metasurface (absorption rate > 99%), forming a "light hotspot" and increasing the local temperature.

[0099] (2) Optimization of optical heat conduction and heat distribution.

[0100] Matching fast transient infrared signals (such as combustion flame flickering, gas leakage pulse), the absorbed light energy is conducted to the pyroelectric layer through the dielectric film layer, and the heat diffusion of the optical hotspot is limited to the local area of ​​the pyroelectric layer, thereby improving the spatial gradient of temperature change and enhancing the polarization charge density of the pyroelectric material.

[0101] (3) Thermoelectric conversion and signal readout.

[0102] Pyroelectric materials (such as LiTaO3 or LiNbO3) spontaneously change their polarization intensity (∆P) in response to temperature changes (∆T). This polarization charge is collected by upper and lower metal electrodes, generating a readout current (∆I_{out}). This current signal is converted to a readout voltage (∆V_{out}) by a low-noise amplifier, ultimately enabling infrared gas detection and precise identification of trace gases.

[0103] This invention systematically breaks through the performance bottleneck of traditional infrared detectors through the innovative design of a mirror-coupled dielectric BIC architecture + pyroelectric collaborative integration, achieving a leap forward in core indicators such as sensitivity and polarization compatibility. The specific performance advantages are as follows:

[0104] 1. Ultra-narrowband high-sensitivity detection (spectral advantage driven by BIC)

[0105] Narrowband absorption breakthrough: Based on the mirror-coupled BIC theory, through the asymmetric perturbation design of dielectric metasurfaces (such as Ge microdisks), the spectrum full width at half maximum (FWHM) is <15 nm (the FWHM of traditional metal MIM structure is > 200), accurately matching the gas absorption peaks (such as CH4 3.31 μm, CO2 4.26 μm, etc.).

[0106] Comparative advantage: No external filter is required, solving the spectral crosstalk problem of the traditional "filter + detector" system. A single detector can achieve narrow-band identification of multiple gas characteristic peaks.

[0107] 2. Full polarization robustness (polarization breakthrough of sporadic BIC).

[0108] Polarization extinction ratio < 1.5 dB: This technology utilizes a symmetry-breaking dielectric metasurface (such as a microdisk array) to excite sporadic BIC modes, breaking the polarization limitations of traditional symmetry-protected BICs. The resulting response variation for incident light polarization states (0°, 45°, 90°, etc.) is < 1.5 dB (compared to the extinction ratio of traditional metal metasurfaces > 10 dB). A single detector unit responds to infrared light of any polarization, supporting confocal integration and compacting the chip area to less than 10 mm², making it suitable for portable spectrometers.

[0109] Adaptability to practical scenarios: No polarization filter components are required, and it is directly compatible with non-polarized infrared radiation in complex environments (such as industrial sites and biological tissue surfaces), simplifying the system architecture.

[0110] 3. Nearly perfect low-loss absorption (material advantage of dielectric metasurface).

[0111] Absorption efficiency > 99%: The all-dielectric metasurface (Ge / Si) avoids metal ohmic losses and, combined with the localized optical field enhancement of the BIC mode, achieves near-perfect absorption in the mid-infrared band (traditional metal MIM absorption efficiency < 80%).

[0112] High-temperature stability: The melting point of dielectric materials (such as SiC) is > 1600°C. Compared with metals (Au melting point 1064°C), it has higher stability in high-power infrared detection scenarios (such as industrial furnace temperature monitoring).

[0113] 4. Process tolerance (process friendliness of accidental BIC).

[0114] Geometric parameter tolerance ±10 nm: accidental BIC design breaks away from the dependence on nanometer-level precision of traditional symmetric structures (absorption efficiency remains > 90% when the disc radius deviation is ±10 nm), is compatible with low-cost processes such as nanoimprint lithography (NIL), and the process error tolerance is improved by an order of magnitude (traditional BIC requires ±1 nm).

[0115] Process simplification: without complex processes such as metal sputtering and stripping, standard IC processes (electron beam lithography, chemical vapor deposition) are used, reducing single-chip processing costs and improving yield.

[0116] 5. Multi-band broad spectrum adaptation (flexibility of structure tuning).

[0117] By adjusting the geometric parameters of the metasurface (such as micro-disk radius 400-800 nm, period 1500-2500 nm), continuous tuning of the detection wavelength is achieved, covering CO2 (4.26 μm), CH4 (3.3 μm), and other gas characteristic bands, supporting simultaneous detection of multiple gases.

[0118] 6. Non-destructive light field side electrode (innovative structure for scene adaptation).

[0119] Light field integrity protection: the side electrode design avoids damage to the BIC light field by opening holes in the upper dielectric film, reduces light field distortion, enhances light field localization, and adapts to scenarios such as surface-enhanced infrared absorption spectroscopy (SEIRAS) that require high precision of light field.

[0120] Packaging compatibility: supports wafer-level fan-out packaging (FOWLP), facilitating integration with microfluidic channels and optical lenses to build miniaturized infrared sensing systems.

[0121] The present application verifies the design scheme of the metasurface infrared detector based on the mirror-coupled dielectric BIC through finite element simulation (software uses CST and COMSOL), and the key simulation results and the accompanying drawings are as follows:

[0122] Figure 2 The infrared detection BIC metasurface structure shows near-perfect absorption (absorption rate > 99%) of the methane characteristic absorption peak (3.31 μm), verifying the narrow-band high-absorption characteristics driven by the BIC mode, and realizing high-sensitivity detection of methane gas.

[0123] Figure 3 When infrared radiation is incident, the field distribution characteristics of energy localized absorption in the metasurface micro-nano structure are presented, directly illustrating the physical mechanism of the mirror-coupled BIC mode enhancing light-heat conversion.

[0124] Figure 4 The high Q value spectrum in the perfect absorption state is exhibited by adjusting the super surface periodic structure parameters, and the narrowband resonance characteristics of the mirror coupled BIC mode are verified (the perfect electric conductor PEC boundary condition is simulated for the metal base, so as to highlight the relationship between the mirror coupled BIC and the structure parameters).

[0125] Figure 5 The near-perfect absorption (absorption rate > 99%) of the CO2 characteristic absorption peak (4.26 μm) is exhibited after adjusting the geometric size of the super surface (such as the radius of the dielectric particles and the period), and the ability of multi-parameter tuning and adaptation to different gas detection is embodied.

[0126] The present application constructs a dielectric super surface microstructure through the mirror coupled BIC theory, realizes high sensitivity and high selectivity detection of infrared electromagnetic signals, and can be widely applied to the fields of gas component analysis, environmental parameter monitoring, biomedical sensing, security monitoring imaging and the like.

[0127] The above only describes the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled persons in the technical field, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A narrow-band metasurface infrared detector based on a mirror-coupled dielectric (BIC), characterized by: It includes a dielectric metasurface functional layer, a dielectric film layer, an upper electrode metal layer, a pyroelectric functional layer and a lower electrode metal layer arranged in sequence from top to bottom. The upper electrode metal layer and the lower electrode metal layer are electrically connected to the test circuit respectively. The dielectric metasurface functional layer includes a plurality of metasurface micro-nanos, which are periodically arranged to form an array form to excite a mirror-coupled occasional BIC mode.

2. The narrow-band metasurface infrared detector based on the mirror-coupled medium (BIC) according to claim 1, characterized in that: The material of the dielectric metasurface functional layer includes Ge or Si, and the shape of the metasurface micro-nanostructure includes a disk, a cube and an elliptical cylinder.

3. The narrow-band metasurface infrared detector based on the mirror-coupled medium (BIC) according to claim 1, characterized in that: The dielectric film layer is made of SiO2, SiC or CaF2, and has a thickness of 50-300 nm.

4. The narrow-band metasurface infrared detector based on the mirror-coupled medium (BIC) according to claim 1, characterized in that: The material of the upper electrode metal layer and the lower electrode metal layer includes Au or Ag, and the thickness is 50-100 nm.

5. The narrow-band metasurface infrared detector based on the mirror-coupled medium (BIC) according to claim 1, characterized in that: The material of the pyroelectric functional layer includes LiTaO3 or LiNbO3, and the thickness is 200-500 nm.

6. The narrow-band metasurface infrared detector based on the mirror-coupled medium (BIC) according to claim 1, characterized in that: The connection methods between the upper electrode metal layer and the lower electrode metal layer and the test circuit include upper and lower contact and side contact. The upper and lower contact is specifically: opening micro-nano through holes on the dielectric film layer to achieve contact between the test circuit and the upper electrode metal layer, and opening through holes on the back side of the substrate to achieve contact between the test circuit and the lower electrode metal layer; the side contact is specifically: leading out the upper and lower electrodes on the sides of the upper electrode metal layer and the lower electrode metal layer and then connecting them to the test circuit.

7. A method for manufacturing a narrow-band metasurface infrared detector based on a mirror-coupled medium (BIC) according to any one of claims 1 to 6, characterized in that: The following steps are involved: The pyroelectric film is cleaned and dried, and then surface activated to obtain a pyroelectric functional layer; Performing metal electrode evaporation on the upper and lower surfaces of the pyroelectric functional layer to form an upper electrode metal layer and a lower electrode metal layer respectively; forming a dielectric film layer on the upper electrode metal layer by chemical vapor deposition; On the upper surface of the dielectric film layer, a micro-nano periodic array of the metasurface is prepared through photolithography and deposition processes to form a dielectric metasurface functional layer, which stimulates the mirror-coupled occasional BIC mode.

8. The method for manufacturing a narrow-band metasurface infrared detector based on a mirror-coupled medium (BIC) according to claim 7, characterized in that: The cleaning of the pyroelectric film includes two steps: organic solvent ultrasonic cleaning and deionized water rinsing; the drying adopts nitrogen blowing; and the surface activation adopts plasma enhanced surface activation.

9. The method for manufacturing a narrow-band metasurface infrared detector based on a mirror-coupled medium (BIC) according to claim 7, characterized in that: The photolithography process includes three steps: coating, exposure and development.

10. The method for manufacturing a narrow-band metasurface infrared detector based on a mirror-coupled medium (BIC) according to claim 7, characterized in that: The deposition process adopts magnetron sputtering.

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