A multi-parameter sensor

Abstract

The application provides a multi-parameter sensor, comprising a light source unit, a sensing unit and a detection unit; wherein the light source unit is arranged to output collimated near-infrared polarized light; the sensing unit comprises a silicon plate with a fan-shaped through hole and a transparent shell for fixing and packaging the silicon plate; and the detection unit is arranged to detect the reflection spectrum of the sensing unit. The multi-parameter sensor provided by the application can realize simultaneous sensing of four parameters affecting the refractive index of a to-be-detected medium, has a sensitivity close to 1000 nm / RIU and a Q value exceeding 10 5 , and is far superior to the prior art in comprehensive index. The multi-parameter sensor provided by the application also has the advantages of simple structure, flexible design and suitability for various complex detection environments.

Description

Technical Field

[0001] This invention relates to optical sensing technology, and in particular to a multi-parameter sensor, belonging to the field of optical detection. Background Technology

[0002] In the field of optical intelligent sensing technology research, micro-nano optical sensors have been widely studied due to their advantages such as real-time operation, label-free operation, high sensitivity, high Q-factor / FOM (Form of Metrics), easy integration, and high cost-effectiveness. However, in order to identify complex samples and further promote the development of highly integrated intelligent sensing platforms, it is necessary not only to improve the accuracy of single-parameter sensing but also to improve the ability of multifunctional composite detection. Multi-parameter sensing technology has become a focus of attention in this field because it can extract rich information from a single data acquisition of the medium under test.

[0003] The number of parameters that a multi-parameter sensing system can measure depends on the number of independent signals obtainable from a single data acquisition. These parameters are acquired in post-processing through demodulation based on their relationship with directly measured data. However, the limited excitation of resonant modes in certain optical sensing structures restricts the development of multi-parameter sensing. In existing technologies, two-parameter sensing technology achieves simultaneous measurement of two parameters by simultaneously exciting two resonant modes, for example, simultaneously measuring temperature and salinity [Dual high-Q resonance sensing for refractive index and temperature based on all-dielectric asymmetric metasurface, Opt. Commun. 554 (2024) 130134. https: / / doi.org / 10.1016 / j.optcom. 2023.130134.]; while three-parameter sensing technology achieves simultaneous measurement of three parameters by simultaneously exciting three resonant modes, for example, simultaneously measuring temperature, salinity and pressure [Refractive Index, Temperature and Pressure Three-Mode Sensing Design Based on Silver-Nitrogen-Graphene Coupled Resonators, IEEE Sens. J. 24 (2024) 8712-8720. https: / / doi.org / 10.1109 / JSEN. 2024. 3357691.]. While some optical structures can simultaneously excite multiple resonant modes, these modes exhibit strong correlations due to their different resonant levels belonging to the same resonant type. This often leads to demodulation failures in subsequent data processing [Simultaneous Measurements of Refractive Index and Methane Concentration through Electromagnetic FanoResonance Coupling in All-Dielectric Metasurface, Sensors 21(2021)3612.https: / / doi.org / 10.3390 / s21113612.]. Furthermore, these different resonant levels often have wide bandwidths or different linewidths, which is detrimental to practical applications.While some meticulously designed optical sensing structures can simultaneously excite multiple resonant modes [Refractive index sensor based on multiple Fanoresonances excited by MIM waveguide couplessd hexagonal nut and square ringresonators, Phys. Scr. 98(2023)075519. https: / / doi.org / 10.1088 / 1402-4896 / acdf26.], these structures are very complex and their sensing performance is relatively mediocre, falling far short of the requirements of modern intelligent sensing.

[0004] Currently, in the field of optical intelligent sensing, the most attention-grabbing micro-nano optical refractive index sensors are divided into two categories: all-dielectric sensors and metal plasma sensors. From the perspective of two indicators characterizing sensing performance—sensitivity (S) and figure of merit (FOM)—each type of sensor has its advantages and disadvantages. Sensitivity mainly depends on the ratio of the optical field mode in the measured medium to the entire resonant mode; the higher the ratio, the higher the sensitivity. FOM is defined as the ratio of sensitivity to the full width at half maximum (FWHM) of the resonance peak. Metal plasma sensors have very high sensitivity because the energy of the resonant mode is difficult to penetrate into the metal, reaching up to 1000-2000 nm / RIU. However, due to intrinsic absorption loss, they also have relatively low FOM. Furthermore, considering chemical stability, metal plasma sensors are not suitable for certain measurement environments, such as seawater and acidic environments. Compared to metal plasma sensors, all-dielectric sensors have advantages such as good chemical stability, low absorption loss, high compatibility with CMOS systems, and high FOM values. However, because resonant modes can easily enter the dielectric structure, the sensitivity of all-dielectric sensors is much lower than that of metal plasma sensors, only tens to hundreds of nm / RIU. Summary of the Invention

[0005] To overcome the shortcomings of the aforementioned technologies, this invention provides an all-dielectric multi-parameter sensor. Among the resonant modes that can be excited by an all-dielectric structure, guided-mode resonances (GMRs) based on grating structures have advantages such as simple structure, rich resonant levels, small mode size for easy integration, and flexible and adjustable operating bands. Therefore, this invention realizes a multi-parameter sensor based on a two-dimensional periodic through-hole all-dielectric structure by exciting four independent GMRs. Through careful structural design, the four resonance peaks in the structure's reflection spectrum exhibit a quasi-BIC (bound state in the continuous spectrum) phenomenon, thereby achieving an extremely narrow resonant linewidth. Simultaneously, through through-hole design and geometric parameter optimization, a sensitivity approaching the theoretical limit of GMRs and comparable to that of metal plasma sensors is achieved.

[0006] This invention provides a multi-parameter sensor, comprising:

[0007] The light source unit is configured to output collimated near-infrared polarized light;

[0008] The sensing unit includes a silicon substrate with fan-shaped through-holes and a transparent housing that securely encapsulates the silicon substrate therein; and

[0009] The detection unit is configured to detect the reflection spectrum of the sensing unit.

[0010] Preferably, the sensing unit is configured such that: the surface of the silicon plate lies in the x, y plane of the x, y, z rectangular coordinate system, and the thickness of the silicon plate is along the z-axis of the x, y, z rectangular coordinate system; the fan-shaped through holes are of the same size and perpendicular to the surface of the silicon plate; four fan-shaped through holes are arranged in a ring to form a structural unit; the structural units are symmetrical about the x and y axes and are periodically distributed on the silicon plate along the x and y directions.

[0011] The inner and outer radii of the sector-shaped through hole are represented by r1 and r2, respectively, and the central angle is represented by θ. c The tilt angle of the sector-shaped through hole relative to the x-axis is represented by θ. x The refractive index of the silicon substrate is represented by n, the thickness of the silicon substrate by d, and the period of the structural unit along the x and y directions by p, respectively. x p y express.

[0012] Preferably, the sensing unit is configured as follows: p x =1200nm, p y =1100nm, r1=250nm, r2=450nm, θ c =40°, θ x =20°, n=1.46, d=500nm.

[0013] Preferably, the light source unit and the sensing unit are configured such that linearly polarized light emitted from the light source unit is incident perpendicularly onto the surface of the silicon substrate, and the polarization direction of the linearly polarized light makes an angle θ with the x-axis. in It is 45°.

[0014] Preferably, the sensing unit is configured such that a small hole is opened on one side of the transparent housing that is perpendicular to the surface of the silicon plate, and the side with the small hole is placed facing upwards for injecting the medium to be measured.

[0015] Optionally, the detection unit is an infrared spectrometer.

[0016] Under the above-mentioned preferred configuration, the multi-parameter sensor provided by the present invention generates four guided mode resonance modes, two of which are TE modes propagating along the x and y directions, respectively, and are labeled as TE. x Model and TE yThe two modules are TM modes propagating along the x and y directions, respectively, and are labeled TM. x Model and TM y The multi-parameter sensor provided by this invention exhibits four resonance peaks in its reflection spectrum, corresponding to TE... x Model, TE y Model, TM x Model and TM y The four resonance peaks are labeled p1, p2, p3, and p4, respectively; when the refractive index n of the medium under test is... s As n gradually increases, the four resonance peaks correspond to n. s The sensitivity to changes in n varies, meaning that the multi-parameter sensor is more sensitive to changes in n. s Four of the parameters simultaneously possess sensing capabilities.

[0017] Optionally, the medium to be measured is seawater, when the n of the seawater s As the value gradually increases from 1.320 to 1.340, the four resonance peaks correspond to n in the order of p1, p2, p3, p4. s The sensitivities were changed to 820 nm / RIU, 829 nm / RIU, 906 nm / RIU, and 915 nm / RIU, respectively, and the Q factors of the four resonance peaks were 1.01 × 10⁻⁶. 5 3.45×10 5 1.07×10 5 and 3.48×10 5 The FOM values ​​of the four resonance peaks are 6.09 × 10⁻⁶. 4 RIU -1 1.92×10 5 RIU -1 6.24×10 4 RIU -1 and 1.96×10 5 RIU -1 .

[0018] The beneficial effects of this invention are as follows: This invention provides a multi-parameter refractive index sensor based on a two-dimensional all-dielectric periodic structure, which can simultaneously sense four parameters affecting the refractive index of the medium being measured. By reducing the filling rate of the dielectric material and introducing structural asymmetry, resulting in the BIC phenomenon, the sensitivity of this multi-parameter sensor approaches 1000 nm / RIU, and the Q value exceeds 10. 5 The overall performance indicators are superior to existing technologies. The multi-parameter sensor provided by this invention also has the advantages of simple structure, flexible design, and applicability to various complex detection environments. Attached Figure Description

[0019] To aid those skilled in the art in understanding the use and implementation of this disclosure, reference is made to the several accompanying drawings for clarity and convenience.

[0020] Figure 1 This is a schematic diagram of the structure of the multi-parameter sensor described in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of the light source unit according to an embodiment of the present invention;

[0022] Figure 3 Figure (a) shows the structure of the silicon plate of the sensing unit according to an embodiment of the present invention, and Figure (b) shows the parameters of the fan-shaped through hole.

[0023] Figure 4 This is a schematic diagram of the transparent housing of the sensing unit according to an embodiment of the present invention;

[0024] Figure 5 The reflection spectrum of the multi-parameter sensor described in this embodiment of the invention and the electromagnetic field distribution of each resonance mode;

[0025] Figure 6 The figures show the detection results of the four resonance peaks of the multi-parameter sensor described in this embodiment of the invention as a function of the refractive index of seawater. Figure (a) shows the wavelength position of the four resonance peaks as a function of the refractive index; Figure (b) shows the sensitivity of the four resonance peaks; and Figure (c) shows the Q factor of the four resonance peaks as a function of the polarization direction θ of the incident light. x The changes. Detailed Implementation

[0026] To better understand the present invention, the following description, in conjunction with embodiments and accompanying drawings, further illustrates the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0027] Example

[0028] like Figure 1 As shown, the multi-parameter sensor proposed in this invention includes: a light source unit configured to output collimated near-infrared polarized light; a sensing unit comprising a silicon plate with fan-shaped through holes and a transparent housing that fixes and encapsulates the silicon plate therein; and a detection unit configured to detect the reflection spectrum of the sensing unit.

[0029] like Figure 2As shown, the light source unit includes a near-infrared light source, a collimating lens group, and a polarizer, arranged sequentially along the optical axis (z-axis). In the field of optical sensing technology research, the near-infrared band has advantages such as high detection sensitivity and easy acquisition of light sources and detectors; therefore, a near-infrared light source is selected as the light source in this embodiment. The light emitted from the near-infrared light source is collimated by the collimating lens group and then incident perpendicularly onto the polarizer, becoming linearly polarized light. By adjusting the transmission direction of the polarizer, the angle θ between the electric field vector of the linearly polarized light and the x-axis can be changed. in .

[0030] Multi-parameter sensors require the excitation of multiple independent resonance modes within a certain frequency band. Compared to one-dimensional periodic structures, two-dimensional periodic structures can support a richer variety of guided-mode resonances (GMRs). For example, when TE or TM polarized light is incident on a one-dimensional grating structure, only TM or TE guided-mode resonances are excited. However, when TE or TM polarized light is incident on a two-dimensional grating structure, both TM and TE guided-mode resonances can be excited in every periodic direction, resulting in the appearance of multiple resonance peaks. Therefore, the sensing unit in this embodiment is implemented using a two-dimensional all-dielectric periodic structure.

[0031] Figure 3 A schematic diagram of the silicon substrate constituting the sensing unit is given. For example... Figure 3 As shown in (a), the sensing unit is configured such that: the surface of the silicon plate lies in the x and y planes, and the thickness of the silicon plate is along the z-axis; the fan-shaped through holes are all the same size and perpendicular to the surface of the silicon plate; every four fan-shaped through holes are arranged in a ring to form a structural unit; the structural units are symmetrical about the x and y axes and are periodically distributed on the silicon plate along the x and y directions. The silicon plate is made of SiO2, the refractive index of SiO2 is represented by n, and the thickness is represented by d. The period of the structural unit along the x and y directions is represented by p. x p y express.

[0032] like Figure 3 As shown in (b), the inner and outer radii of the fan-shaped through hole are represented by r1 and r2, respectively, and the central angle is represented by θ. c The tilt angle of the sector-shaped through-hole relative to the x-axis is represented by θ. x The tilt angle relative to the y-axis is represented by θ. y This can be easily obtained from geometric relationships, θ y =90°-θ c -θ x .

[0033] A periodic two-dimensional structure with through-holes can excite GMRs propagating along each periodic direction. For example, when the electric field vector of vertically incident linearly polarized light has components along the x and y directions, under the condition of GMR wave vector matching, TE and TM GMRs can be simultaneously excited in each periodic direction of the two-dimensional structure. This can be achieved by setting θ...x ≠θ y Or p x ≠p y When the symmetry of the structure is broken, these resonance modes do not overlap, forming multiple independent resonance peaks that do not overlap with each other in terms of spectrum. Even considering only the first-order (m=1) resonance mode, the silicon plate structure with periodic through holes in this embodiment can simultaneously excite four independent resonance modes, thereby realizing multi-parameter sensing.

[0034] For periodic structures that support GMRs and are used as refractive index sensors, sensing sensitivity (S) and figure of merit (FOM) are two important metrics, which are given by the following formulas:

[0035]

[0036]

[0037] Where, λ R n is the resonant wavelength. s ρ is the refractive index of the medium under test, p is the period of the sensor structure, m is the mode level of the GMRs, and S is the refractive index of the medium under test. N It is the standardized sensitivity, defined as the effective refractive index n of the waveguide layer in the sensor structure. eff With the refractive index n of the medium under test s The rate of change, mathematically expressed as: W and Q are the full width at half maximum (FWHM) and quality factor of the resonance peaks of GMRs, respectively.

[0038] As can be seen from formula (1), in order to increase S, the mode level m of GMRs should be 1. Furthermore, since S increases with increasing p, the designed periodic structure should have as large a period as possible. However, the period of the structure determines the resonance wavelength λ of the GMRs. R The resonance wavelength λ of GMRs R The structure's period p must be adapted to the sensor's operating wavelength, therefore the period p cannot be increased indefinitely. Based on the above analysis, for a given operating wavelength band, the sensor's performance depends on only two parameters, S... N And Q. The larger these two parameters are, the higher the sensor's performance. S NThe increase in Q can be achieved by increasing the fill rate of the test medium in the waveguide layer. For silicon substrates with periodic vias, this can be achieved by increasing the fill rate of the vias while keeping other parameters constant. For obtaining high Q values, realizing bound states (BICs) in the continuous spectrum within the periodic structure of the sensor is a very effective method. For sensor structures that excite multiple GMRs, it is necessary to realize BICs simultaneously near multiple resonance peaks. When a resonance peak occurs near the conditions for BIC realization, the resonance peak becomes exceptionally sharp, thereby effectively increasing the Q value of the resonance peak. There are various types of BICs, among which symmetry-protected BICs are relatively easy to implement. They can be achieved by breaking the symmetry in the periodic structure. In this embodiment, this can be achieved by adjusting θ. x To achieve this.

[0039] Based on the above analysis, in this embodiment, after parameter optimization, the parameters of the sensing unit are set as follows: p x =1200nm, p y =1100nm, r1=250nm, r2=450nm, θ c =40°, θ x =20°, n=1.46, d=500nm. The angle θ between the polarization direction of linearly polarized light and the x-axis. in The angle is set to 45°.

[0040] like Figure 4 As shown, to facilitate the injection of the test medium, a small hole is formed on the side of the transparent housing of the sensing unit that is perpendicular to the surface of the silicon plate, and this side with the small hole is placed upwards for injecting the test medium. The transparent housing is made of glass.

[0041] The detection unit is configured to include an infrared spectrometer to receive the reflection spectrum of the sensing unit.

[0042] The refractive index n of the medium under test s Set to 1, the multi-parameter sensor of this embodiment is simulated using commercial software (Comsol MultiPhysics). Figure 5 The calculated reflection spectrum and electromagnetic field distribution for each resonance mode are presented. As can be seen from the figure, four sharp GMR resonance peaks appear in the reflection spectrum within the 1100 nm to 1500 nm wavelength range. The electromagnetic field distribution in the figure indicates that four guided-mode resonances are generated in this multi-parameter sensor. From left to right, the first resonance peak p1 and the second resonance peak p2 correspond to the TE mode propagating along the x and y directions, respectively, while the third resonance peak p3 and the fourth resonance peak p4 correspond to the TM mode propagating along the x and y directions, respectively.

[0043] To evaluate the sensing performance of the multi-parameter sensor with four peaks, its sensing capability for seawater was further simulated. The refractive index n of seawater was calculated based on the typical salinity variation range. s It will vary between 1.320 and 1.340. The simulation results are as follows... Figure 6 As shown. Figure 6 (a) shows the wavelength positions of the four resonance peaks as a function of refractive index. The labels of the four peaks in the figure are... Figure 5 The four peaks are labeled identically: p1 and p2 correspond to the TE GMR resonance peaks propagating along the x and y directions, respectively, while p3 and p4 correspond to the TM GMR resonance peaks propagating along the x and y directions, respectively. For small changes in refractive index, the wavelength positions of all four resonance peaks show a significant linear change. Figure (b) shows the sensing sensitivities at the four resonance wavelengths: 820 nm / RIU, 829 nm / RIU, 906 nm / RIU, and 915 nm / RIU, all exceeding the sensitivity of most all-dielectric refractive index sensors and almost comparable to most plasma sensors. The figure also shows that the sensitivities of p2 and p4 are higher than those of p1 and p3, meaning the sensitivity of the resonance mode propagating along the y direction is greater than that along the x direction. This is because the period p along the x direction... x Slightly larger than the period p along the y-direction y A larger period indicates a smaller filling rate of the through-hole in that direction, and according to the theoretical formula (1), the sensitivity under this condition is lower. Furthermore, this embodiment also provides the Q factor and FOM value for the four resonance peaks. Figure 6 (c) represents the Q factor of the four resonant modes as a function of θ. x The change. In the calculation, except for θ x θ y All other parameters remain unchanged, and the refractive index of seawater is taken as the median n. s =1.330. Since both resonance peaks p1 and p3 propagate along the x-direction, the conditions for BIC formation are the same for them. When adjusting θ... x When altering the structural asymmetry, it was found that for resonance peaks p1 and p3BICs, the occurrence at θ... x =11.6°, similarly, for resonance peaks p2 and p4, BICs occur at θ. x = 31.3°. Therefore, these two θ values... x The angle and θ in the optimized parameters used in this embodiment x The 20° difference is almost equal, so for the sensor structure with optimized parameters in this embodiment, all four GMR modes can be considered quasi-BIC. Under these conditions, the Q factors of the four GMR resonance peaks p1, p2, p3, and p4 reach 1.01 × 10⁻⁶. 53.45×10 5 1.07×10 5 and 3.48×10 5 Accordingly, the FOM values ​​of p1, p2, p3, and p4 can be calculated to be 6.09 × 10⁻⁶. 4 RIU -1 1.92×10 5 RIU -1 6.24×10 4 RIU -1 and 1.96×10 5 RIU -1 These FOM values ​​are significantly higher than those of all metal plasma sensors in the prior art, and are not low compared to high FOM all-dielectric sensors in the prior art.

[0044] To illustrate the multi-parameter sensing capability of the multi-parameter sensor in this embodiment, the concentrations of various components constituting seawater are demodulated using four resonant wavelengths. According to the literature [A. Bain, A. Rafferty, TCPreston, The Wavelength-Dependent Complex Refractive Index of Hygroscopic Aerosol Particles and Other Aqueous Media: An Effective Oscillator Model, Geophys. Res. Lett. 46(2019) 10636-10645. https: / / doi.org / 10.1029 / 2019GL084568], the refractive index of seawater containing specific components is expressed as:

[0045]

[0046] Where ν is the frequency of light, φ α n represents the concentration of different components. w (ν) represents the refractive index of pure water. and This represents the refractive index coefficient corresponding to different salinity components. In this embodiment, we only consider the four main components of seawater: NaCl, NaNO3, (NH4)2SO4, and MgSO4. Their refractive index coefficients are shown in the table below:

[0047] Refractive index coefficients of different components of seawater:

[0048]

[0049] set up The refractive index of seawater can then be rewritten as:

[0050]

[0051] When seawater composed of the above four main components at a certain concentration is used as the test medium, the multi-parameter sensor provided in this embodiment will produce four resonance peaks. The resonance wavelengths corresponding to the four resonance peaks are denoted as λ. l (l = 1, 2, 3, 4). The refractive indices corresponding to these four wavelengths are represented as n1(λ1), n2(λ2), n3(λ3), and n4(λ4), respectively. At each resonant wavelength λ... l Based on the above refractive index formula, an equation can be written as follows:

[0052]

[0053] Among them, v l =1 / λ l This yields four non-homogeneous linear equations, forming a fourth-order non-homogeneous linear system of equations. It can be proven that the coefficient matrix of this system of equations has no zero elements and cannot be linearly represented by any other matrix element. Therefore, this system of equations has a unique solution. Similar to other two-parameter sensing methods [P.Sun,Q.Zhao,Y.Li,S.Liu,C.Su,J.Jiang,M.Yun,Y.Zhao,J.Wang,Dual high-Q resonancesensing for refractive index and temperature based on all-dielectricasymmetric metasurface,Opt.Commun.554(2024)130134.https: / / doi.org / 10.1016 / j.optcom.2023.130134.], by solving this system of equations, each φ can be obtained. α The value of .

[0054] Those skilled in the art should understand that all modifications or combinations made to the present invention based on the technical content described in the above embodiments are within the scope of protection of the claims of the present invention.

Claims

1. A multi-parameter sensor, characterized in that, include: The light source unit is configured to output collimated near-infrared polarized light; The sensing unit includes a silicon plate with fan-shaped through-holes and a transparent housing that securely encapsulates the silicon plate therein; and A detection unit configured to detect the reflection spectrum of the sensing unit; The sensing unit is configured as follows: The surface of the silicon plate lies in the x, y plane of the x, y, z rectangular coordinate system, and the thickness of the silicon plate is along the z-axis direction of the x, y, z rectangular coordinate system. The fan-shaped through holes are all the same size and are perpendicular to the surface of the silicon substrate; The four fan-shaped through holes are arranged in a ring to form a structural unit; The structural units are symmetrical about the x and y axes and are periodically distributed on the silicon plate along the x and y directions; The inner and outer radii of the sector-shaped through hole are represented by r1 and r2, respectively, and the central angle of the sector-shaped through hole is represented by θ. c The inclination angle of the fan-shaped through hole relative to the x-axis is represented by θ. x The tilt angle relative to the y-axis is represented by θ. y It means that θ x ≠θ y The refractive index of the silicon plate is represented by n, the thickness of the silicon plate is represented by d, and the period of the structural unit along the x and y directions is represented by p, respectively. x p y It means that p x ≠p y ; The light source unit is configured such that linearly polarized light emitted from the light source unit is incident perpendicularly onto the surface of the silicon substrate, and the polarization direction of the linearly polarized light makes an angle θ with the x-axis. in 45 o .

2. The multi-parameter sensor as described in claim 1, characterized in that, in, The sensing unit is configured as follows: p x =1200nm, p y =1100nm, r1=250nm, r2=450nm, θ c =40 o θ x =20 o , n=1.46, d=500nm.

3. The multi-parameter sensor as described in claim 1, characterized in that, in, The sensing unit is configured such that a small hole is opened on one side of the transparent housing that is perpendicular to the surface of the silicon plate, and the side with the small hole is placed facing upwards for injecting the medium to be measured.

4. The multi-parameter sensor as described in claim 1, characterized in that, in, The detection unit is an infrared spectrometer.

5. The multi-parameter sensor as described in claim 1, characterized in that, in, The light source unit is configured to include a near-infrared light source, a collimating lens group, and a polarizer.

6. The multi-parameter sensor as described in claim 2, characterized in that, The multi-parameter sensor generates four guided mode resonance modes; Two of the four guided mode resonant modes are TE modes propagating along the x and y directions, respectively, and are labeled as TE. x Model and TE y mold; Two of the four guided mode resonant modes are TM modes propagating along the x and y directions, respectively, and are labeled as TM. x Model and TM y mold; The reflection spectrum of the multi-parameter sensor shows four resonance peaks, corresponding to TE... x Model, TE y Model, TM x Model and TM y The four resonance peaks are labeled p1, p2, p3, and p4, respectively. When the refractive index n of the medium under test s When the wavelength changes, all four resonance peaks gradually shift towards longer wavelengths, and the four resonance peaks affect n. s The sensitivity to changes in n varies, meaning that the multi-parameter sensor is more sensitive to changes in n. s Four of the parameters simultaneously possess sensing capabilities.

7. The multi-parameter sensor as described in claim 6, characterized in that, in, The medium to be tested is seawater; For n s The gradual change from 1.320 to 1.340, the four resonance peaks p1, p2, p3, p4, correspond to n. s The sensitivities were changed sequentially to 820 nm / RIU, 829 nm / RIU, 906 nm / RIU, and 915 nm / RIU, and the Q factors of the four resonance peaks p1, p2, p3, and p4 were 1.01 × 10⁻⁶, respectively. 5 3.45×10 5 1.07×10 5 and 3.48×10 5 The FOMs of p1, p2, p3, and p4 are respectively 6.09 × 10 4 RIU -1 1.92×10 5 RIU -1 6.24×10 4 RIU -1 and 1.96×10 5 RIU -1 .

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