All-dielectric terahertz sensor based on asymmetric eccentric circle structure and application

Abstract

The invention discloses an all-dielectric terahertz sensor based on an asymmetric eccentric circle structure, which comprises a quartz substrate layer, a plurality of unit cells arranged periodically are arranged on the quartz substrate layer, the structures of the plurality of unit cells are the same, each unit cell comprises a cylindrical silicon dielectric layer, and a through eccentric hole is vertically formed in the silicon dielectric layer. The invention further discloses application of the all-dielectric terahertz sensor based on the asymmetric eccentric circle structure. According to the invention, the problem of polarization interference in the prior art is solved, and accurate response of target polarization signals and non-target interference shielding are realized.

Description

Technical Field

[0001] This invention belongs to the field of terahertz functional devices and high-sensitivity sensing technology, specifically relating to an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure. This invention also relates to the application of an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure. Background Technology

[0002] Terahertz waves refer to electromagnetic waves with frequencies ranging from 0.1 terahertz to 10 terahertz (THz), with wavelengths between microwaves and infrared waves. Due to their fingerprint spectral characteristics and low-energy, lossless operation, they have attracted considerable attention in the sensing field. However, their weak interactions with natural materials have resulted in a lack of high-performance THz devices. Therefore, artificially designed and fabricated subwavelength micro / nanostructure arrays with novel optical properties offer the ability to flexibly and efficiently manipulate THz waves. However, the quality factor of the resonant peak of terahertz-based metasurface sensors (…) remains a concern. Q The energy loss (value) is limited to tens to hundreds due to the high energy loss caused by multiple factors such as terahertz frequency band characteristics, material properties, structural design and manufacturing process.

[0003] Bound states (BICs) in a continuum are theoretically infinite. Q The nonradiative state of the factor, which is decoupled from the continuum to prevent energy leakage, can significantly increase the performance of metasurface resonators. Q Value, high Q High-resolution resonators can significantly enhance the interaction between the structure and light, and are therefore widely used for the detection of trace substances. Existing THz all-dielectric BIC sensors suffer from two key limitations: firstly, symmetrical unit cell structures utilize mode interference to form a single BIC resonant peak, resulting in a limited number of modes and a single function; secondly, even when some schemes introduce dual polarization directions, insufficient structural design often leads to overlap of BIC mode frequencies in the two polarization directions. This not only fails to achieve a stable polarization response but also makes them susceptible to interference from waves of non-target polarization directions, resulting in weak anti-interference capabilities and severely impacting sensing stability and signal accuracy. Summary of the Invention

[0004] The purpose of this invention is to provide an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure, which solves the polarization interference problem existing in the prior art and achieves accurate response to the target polarization signal and shielding against non-target interference.

[0005] Another objective of this invention is to provide applications for all-dielectric terahertz sensors based on an asymmetric eccentric circular structure.

[0006] The first technical solution adopted in this invention is that the present invention is a fully dielectric terahertz sensor based on an asymmetric eccentric circular structure, including a quartz substrate layer, on which a number of periodically arranged unit cells are disposed, the number of unit cells having the same structure, each unit cell including a cylindrical silicon dielectric layer, and a through eccentric hole vertically opened on the silicon dielectric layer.

[0007] The first technical solution of the present invention is further characterized in that,

[0008] The perpendicular bisectors of the eccentric hole, the silicon dielectric layer, and the quartz substrate are all parallel to each other.

[0009] The distance between the center of the eccentric hole and the center of the silicon dielectric layer is 1-65 μm.

[0010] The array formed by several unit cells is a periodic array of 4×4 matrices.

[0011] The thickness of the silicon bulk dielectric layer is h 1, its range is 50-150µm.

[0012] The thickness of the quartz substrate is h 2, of which h 2=5 h 1.

[0013] The quartz substrate has a square structure.

[0014] The second technical solution adopted in this invention is based on the application of an all-dielectric terahertz sensor with an asymmetric eccentric circular structure, relying on a polarization-direction-sensitive BIC control mechanism to achieve accurate differentiation and identification of multiple trace substances in a mixed system.

[0015] The second technical solution of the present invention is further characterized in that, Specifically, by introducing perturbations into the metasurface unit cell to break the symmetry, the local electromagnetic field of the ideal BIC is partially coupled to the far field to form a quasi-BIC mode. This mode combines high performance with low latency. Q Factor characteristics and observable far-field response; simultaneously, by controlling the incident directions of X and Y orthogonally polarized terahertz waves, multiple non-interfering quasi-BIC modes are excited by polarized light in different directions, each mode corresponding to a dedicated detection channel, and the resonance frequencies of different channels, Q Significant differences exist between the factors and near-field enhancement regions. When the mixed material is loaded onto the metasurface, the terahertz fingerprint characteristics of different components are quite different, and they will produce selective responses to specific frequency points of specific polarization channels. Such characteristics can be applied to the detection of trace amounts of biomolecules, analysis of chemical composition, or precise identification of environmental pollutants.

[0016] The beneficial effects of this invention are that the all-dielectric terahertz sensor based on an asymmetric eccentric circular structure has a simple structure and is easy to manufacture; high efficiency... Q The factor is determined by the energy-leakage-free and continuum-decoupled characteristics of the BIC mode, and the BIC modes in the X and Y polarization directions. Q The value is extremely high, far exceeding that of traditional terahertz metasurface sensors; excellent polarization selectivity and anti-interference performance: the X and Y polarization directions correspond to 2 and 4 independent BIC modes respectively, and the mode frequencies are completely staggered, generating a strong resonant response only for terahertz waves in the target polarization direction; waves in non-target polarization directions cannot excite the corresponding BIC modes, effectively solving the signal interference problem under different polarization incident directions, and ensuring the accuracy and stability of the data. Attached Figure Description

[0017] Figure 1(a) is a top view of the all-dielectric terahertz sensor unit structure based on the asymmetric eccentric circular structure of the present invention; Figure 1(b) is a three-dimensional side view of the all-dielectric terahertz sensor unit structure based on the asymmetric eccentric circular structure of the present invention; Figure 2 This is a three-dimensional view of the overall structure of the all-dielectric terahertz sensor based on the asymmetric eccentric circular structure of the present invention; Figure 3 This invention relates to the transmission spectra of THz waves with and without altered horizontal offset in the X-incidence direction. Figure 4 This invention relates to the transmission spectra of THz waves with and without altered horizontal offset in the Y-incidence direction. Figure 5 This invention is in f The relationship between the resonant frequency of the metasurface designed in the QBIC mode corresponding to 1 and the refractive index of the analyte; Figure 6 This invention is in f The graph shows the relationship between the resonant frequency of the metasurface designed in the QBIC mode corresponding to 3 and the refractive index of the analyte.

[0018] In the figure, 1. silicon dielectric layer, 2. quartz substrate layer. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] This invention relates to an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure, as shown in Figures 1(a) and 1(b). Figure 2 It includes a quartz substrate layer 2, on which a number of periodically arranged unit cells 3 are disposed. The unit cells 3 have the same structure. Each unit cell 3 includes a cylindrical silicon dielectric layer 1, on which a through eccentric hole 4 is vertically opened.

[0021] The perpendicular bisector of the eccentric hole 4, the perpendicular bisector of the silicon dielectric layer 1, and the perpendicular bisector of the quartz substrate layer 2 are all parallel to each other.

[0022] The distance between the center of the eccentric hole 4 and the center of the silicon dielectric layer 1 is 1-65 μm.

[0023] The array formed by several unit cells 3 is a periodic array of 4×4 matrices.

[0024] The thickness of silicon bulk dielectric layer 1 is h 1, its range is 50-150µm.

[0025] The thickness of quartz substrate 2 is h 2, of which h 2=5 h 1.

[0026] The quartz substrate layer 2 has a square structure.

[0027] This invention is based on the application of an all-dielectric terahertz sensor with an asymmetric eccentric circular structure, relying on a polarization-direction-sensitive BIC control mechanism to achieve accurate differentiation and identification of multiple trace substances in a mixed system.

[0028] Specifically, by introducing perturbations into the metasurface unit cell to break the symmetry, the local electromagnetic field of the ideal BIC is partially coupled to the far field to form a quasi-BIC mode. This mode combines high performance with low latency. Q Factor characteristics and observable far-field response; simultaneously, by controlling the incident directions of X and Y orthogonally polarized terahertz waves, multiple non-interfering quasi-BIC modes are excited by polarized light in different directions, each mode corresponding to a dedicated detection channel, and the resonance frequencies of different channels, Q Significant differences exist between the factors and near-field enhancement regions. When the mixed material is loaded onto the metasurface, the terahertz fingerprint characteristics of different components are quite different, and they will produce selective responses to specific frequency points of specific polarization channels. Such characteristics can be applied to the detection of trace amounts of biomolecules, analysis of chemical composition, or precise identification of environmental pollutants.

[0029] Example 1 This invention relates to an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure. The sensor is composed of periodically arranged unit cells, each consisting of: 1. a cylindrical silicon dielectric layer with a circular hole; 2. a square quartz substrate layer. By controlling the geometric asymmetry in the X-direction (such as silicon eccentric offset), an asymmetric perturbation is introduced, which can induce multiple ultra-high frequency staggered and non-overlapping field distributions in the X and Y orthogonal electric field polarization directions. QThe metasurface designed with the quasi-continuum bound state (BIC) resonance absorption peak exhibits polarization direction selectivity, making it particularly suitable for scenarios such as trace detection of biomolecules, analysis of chemical composition, and precise identification of environmental pollutants under different polarization incident environments.

[0030] Example 2 The present invention relates to an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure, comprising a quartz substrate layer 2, on which a plurality of periodically arranged unit cells 3 are disposed, the unit cells 3 having the same structure, each unit cell 3 comprising a cylindrical silicon dielectric layer 1, on which a through eccentric hole 4 is vertically opened.

[0031] The perpendicular bisector of the eccentric hole 4, the perpendicular bisector of the silicon dielectric layer 1, and the perpendicular bisector of the quartz substrate layer 2 are all parallel to each other.

[0032] The distance between the center of the eccentric hole 4 and the center of the silicon dielectric layer 1 is 1-65 μm.

[0033] The array formed by several unit cells 3 is a periodic array of 4×4 matrices.

[0034] Example 3 The present invention relates to an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure, comprising a quartz substrate layer 2, on which a plurality of periodically arranged unit cells 3 are disposed, the unit cells 3 having the same structure, each unit cell 3 comprising a cylindrical silicon dielectric layer 1, on which a through eccentric hole 4 is vertically opened.

[0035] The perpendicular bisector of the eccentric hole 4, the perpendicular bisector of the silicon dielectric layer 1, and the perpendicular bisector of the quartz substrate layer 2 are all parallel to each other.

[0036] The array formed by several unit cells 3 is a periodic array of 4×4 matrices.

[0037] Example 4 The present invention relates to an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure, comprising a quartz substrate layer 2, on which a plurality of periodically arranged unit cells 3 are disposed, the unit cells 3 having the same structure, each unit cell 3 comprising a cylindrical silicon dielectric layer 1, on which a through eccentric hole 4 is vertically opened.

[0038] The perpendicular bisector of the eccentric hole 4, the perpendicular bisector of the silicon dielectric layer 1, and the perpendicular bisector of the quartz substrate layer 2 are all parallel to each other.

[0039] The distance between the center of the eccentric hole 4 and the center of the silicon dielectric layer 1 is 1-65 μm.

[0040] The array formed by several unit cells 3 is a periodic array of 4×4 matrices.

[0041] The thickness of silicon bulk dielectric layer 1 is h 1, its range is 50-150µm.

[0042] Example 5 The present invention relates to an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure, comprising a quartz substrate layer 2, on which a plurality of periodically arranged unit cells 3 are disposed, the unit cells 3 having the same structure, each unit cell 3 comprising a cylindrical silicon dielectric layer 1, on which a through eccentric hole 4 is vertically opened.

[0043] The perpendicular bisector of the eccentric hole 4, the perpendicular bisector of the silicon dielectric layer 1, and the perpendicular bisector of the quartz substrate layer 2 are all parallel to each other.

[0044] The distance between the center of the eccentric hole 4 and the center of the silicon dielectric layer 1 is 1-65 μm.

[0045] The array formed by several unit cells 3 is a periodic array of 4×4 matrices.

[0046] The thickness of silicon bulk dielectric layer 1 is h 1, its range is 50-150µm.

[0047] The thickness of quartz substrate 2 is h 2, of which h 2=5 h 1.

[0048] Example 6 This invention is based on the application of an all-dielectric terahertz sensor with an asymmetric eccentric circular structure, relying on a polarization-direction-sensitive BIC control mechanism to achieve accurate differentiation and identification of multiple trace substances in a mixed system.

[0049] Combination Figures 3-6 Specifically, by introducing perturbations into the metasurface unit cell to break the symmetry, the local electromagnetic field of the ideal BIC is partially coupled to the far field to form a quasi-BIC mode. This mode combines high performance with high stability. Q Factor characteristics and observable far-field response; simultaneously, by controlling the incident directions of X and Y orthogonally polarized terahertz waves, multiple non-interfering quasi-BIC modes are excited by polarized light in different directions, each mode corresponding to a dedicated detection channel, and the resonance frequencies of different channels, Q Significant differences exist between the factors and near-field enhancement regions. When the mixed material is loaded onto the metasurface, the terahertz fingerprint characteristics of different components are quite different, and they will produce selective responses to specific frequency points of specific polarization channels. Such characteristics can be applied to the detection of trace amounts of biomolecules, analysis of chemical composition, or precise identification of environmental pollutants. Figure 3 This invention relates to the transmission spectra of THz waves with and without altered horizontal offset in the X-incidence direction. Figure 4 This invention relates to the transmission spectra of THz waves with and without altered horizontal offset in the Y-incidence direction. Figure 5 This invention is in f The relationship between the resonant frequency of the metasurface designed in the QBIC mode corresponding to 1 and the refractive index of the analyte; Figure 6 This invention is in f The graph shows the relationship between the resonant frequency of the metasurface designed in the QBIC mode corresponding to 3 and the refractive index of the analyte.

[0050] Example 7 This invention relates to an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure, as shown in Figures 1(a) and 1(b). Figure 2 It includes a quartz substrate layer 2, on which a number of periodically arranged unit cells 3 are disposed. The unit cells 3 have the same structure. Each unit cell 3 includes a cylindrical silicon dielectric layer 1, on which a through eccentric hole 4 is vertically opened.

[0051] The array formed by several unit cells 3 is a periodic array of 4×4 matrices.

[0052] The thickness of silicon bulk dielectric layer 1 is h 1, its range is 50-150µm.

[0053] The thickness of quartz substrate 2 is h 2, of which h 2=5 h 1.

[0054] The quartz substrate layer 2 has a square structure.

[0055] This invention is based on the application of an all-dielectric terahertz sensor with an asymmetric eccentric circular structure, relying on a polarization-direction-sensitive BIC control mechanism to achieve accurate differentiation and identification of multiple trace substances in a mixed system.

[0056] Specifically, by introducing perturbations into the metasurface unit cell to break the symmetry, the local electromagnetic field of the ideal BIC is partially coupled to the far field to form a quasi-BIC mode. This mode combines high performance with low latency. Q Factor characteristics and observable far-field response; simultaneously, by controlling the incident directions of X and Y orthogonally polarized terahertz waves, multiple non-interfering quasi-BIC modes are excited by polarized light in different directions, each mode corresponding to a dedicated detection channel, and the resonance frequencies of different channels, Q Significant differences exist between the factors and near-field enhancement regions. When the mixed material is loaded onto the metasurface, the terahertz fingerprint characteristics of different components are quite different, and they will produce selective responses to specific frequency points of specific polarization channels. Such characteristics can be applied to the detection of trace amounts of biomolecules, analysis of chemical composition, or precise identification of environmental pollutants.

[0057] Example 8 This invention relates to an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure, as shown in Figures 1(a) and 1(b). Figure 2 It includes a quartz substrate layer 2, on which a number of periodically arranged unit cells 3 are disposed. The unit cells 3 have the same structure. Each unit cell 3 includes a cylindrical silicon dielectric layer 1, on which a through eccentric hole 4 is vertically opened.

[0058] The perpendicular bisector of the eccentric hole 4, the perpendicular bisector of the silicon dielectric layer 1, and the perpendicular bisector of the quartz substrate layer 2 are all parallel to each other.

[0059] The distance between the center of the eccentric hole 4 and the center of the silicon dielectric layer 1 is 1-65 μm.

[0060] The array formed by several unit cells 3 is a periodic array of 4×4 matrices.

[0061] The quartz substrate layer 2 has a square structure.

[0062] This invention is based on the application of an all-dielectric terahertz sensor with an asymmetric eccentric circular structure, relying on a polarization-direction-sensitive BIC control mechanism to achieve accurate differentiation and identification of multiple trace substances in a mixed system.

[0063] Specifically, by introducing perturbations into the metasurface unit cell to break the symmetry, the local electromagnetic field of the ideal BIC is partially coupled to the far field to form a quasi-BIC mode. This mode combines high performance with low latency. Q Factor characteristics and observable far-field response; simultaneously, by controlling the incident directions of X and Y orthogonally polarized terahertz waves, multiple non-interfering quasi-BIC modes are excited by polarized light in different directions, each mode corresponding to a dedicated detection channel, and the resonance frequencies of different channels, Q Significant differences exist between the factors and near-field enhancement regions. When the mixed material is loaded onto the metasurface, the terahertz fingerprint characteristics of different components are quite different, and they will produce selective responses to specific frequency points of specific polarization channels. Such characteristics can be applied to the detection of trace amounts of biomolecules, analysis of chemical composition, or precise identification of environmental pollutants.

[0064] Example 9 This invention relates to an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure, as shown in Figures 1(a) and 1(b). Figure 2 It includes a quartz substrate layer 2, on which a number of periodically arranged unit cells 3 are disposed. The unit cells 3 have the same structure. Each unit cell 3 includes a cylindrical silicon dielectric layer 1, on which a through eccentric hole 4 is vertically opened.

[0065] The perpendicular bisector of the eccentric hole 4, the perpendicular bisector of the silicon dielectric layer 1, and the perpendicular bisector of the quartz substrate layer 2 are all parallel to each other.

[0066] This invention is based on the application of an all-dielectric terahertz sensor with an asymmetric eccentric circular structure, relying on a polarization-direction-sensitive BIC control mechanism to achieve accurate differentiation and identification of multiple trace substances in a mixed system.

[0067] Specifically, by introducing perturbations into the metasurface unit cell to break the symmetry, the local electromagnetic field of the ideal BIC is partially coupled to the far field to form a quasi-BIC mode. This mode combines high performance with low latency. Q Factor characteristics and observable far-field response; simultaneously, by controlling the incident directions of X and Y orthogonally polarized terahertz waves, multiple non-interfering quasi-BIC modes are excited by polarized light in different directions, each mode corresponding to a dedicated detection channel, and the resonance frequencies of different channels, Q Significant differences exist between the factors and near-field enhancement regions. When the mixed material is loaded onto the metasurface, the terahertz fingerprint characteristics of different components are quite different, and they will produce selective responses to specific frequency points of specific polarization channels. Such characteristics can be applied to the detection of trace amounts of biomolecules, analysis of chemical composition, or precise identification of environmental pollutants.

[0068] This invention has an ultra-high design Q The core of this polarization-selective THz all-dielectric sensor lies in its ability to excite multiple independent BIC resonant modes in both the X and Y orthogonal electric field polarization directions by disrupting the geometric symmetry in the X direction (i.e., adjusting the eccentric shift of the silicon structure within the unit cell). By precisely optimizing the asymmetry parameters in the X direction, the multiple BIC modes excited under X-polarized incidence and those under Y-polarized incidence are completely frequency-separated and their field distributions do not overlap. This avoids both the absence of BIC response in a particular polarization direction due to a single-directional structural disruption and cross-interference between modes in different polarization directions. This design retains the ultra-high polarization efficiency of the BIC modes. Q The value characteristics ensure that the device has high sensitivity and can accurately identify and respond to incident signals in the target polarization direction, while shielding interference from waves in non-target polarization directions. This greatly improves the sensor's anti-interference ability and signal resolution in complex polarization incident environments, meeting the multiple requirements for detection accuracy, polarization selectivity and stability in actual sensing scenarios.

Claims

1. A fully dielectric terahertz sensor based on an asymmetric eccentric circular structure, characterized in that, It includes a quartz substrate layer (2), on which a number of periodically arranged unit cells (3) are provided. The structure of the unit cells (3) is the same. Each unit cell (3) includes a cylindrical silicon dielectric layer (1), and a through eccentric hole (4) is vertically opened on the silicon dielectric layer (1).

2. The all-dielectric terahertz sensor based on an asymmetric eccentric circular structure according to claim 1, characterized in that, The perpendicular line of the eccentric hole (4), the perpendicular line of the silicon dielectric layer (1), and the perpendicular line of the quartz substrate layer (2) are all parallel to each other.

3. The all-dielectric terahertz sensor based on an asymmetric eccentric circular structure according to claim 1, characterized in that, The distance between the center of the eccentric hole (4) and the center of the silicon dielectric layer (1) is 1-65 μm.

4. The all-dielectric terahertz sensor based on an asymmetric eccentric circular structure according to claim 1, characterized in that, The array formed by several of the said unit cells (3) is a periodic array of 4×4 matrices.

5. The all-dielectric terahertz sensor based on an asymmetric eccentric circular structure according to claim 1, characterized in that, The thickness of the silicon dielectric layer (1) is h 1, its range is 50-150µm.

6. The all-dielectric terahertz sensor based on an asymmetric eccentric circular structure according to claim 1, characterized in that, The thickness of the quartz substrate layer (2) is h 2, of which h 2=5 h 1.

7. The all-dielectric terahertz sensor based on an asymmetric eccentric circular structure according to claim 1, characterized in that, The quartz substrate layer (2) has a square structure.

8. Application of an all-dielectric terahertz sensor based on an asymmetric eccentric circular structure, characterized in that, By relying on the polarization-direction-sensitive BIC control mechanism, the precise differentiation and identification of multiple trace substances in the mixed system can be achieved.

9. The application of the all-dielectric terahertz sensor based on an asymmetric eccentric circular structure according to claim 8, characterized in that, Specifically, by introducing perturbations into the metasurface unit cell to break the symmetry, the local electromagnetic field of the ideal BIC is partially coupled to the far field to form a quasi-BIC mode. This mode combines high performance with high stability. Q Factor characteristics and observable far-field response; simultaneously, by controlling the incident directions of X and Y orthogonally polarized terahertz waves, multiple non-interfering quasi-BIC modes are excited by polarized light in different directions, each mode corresponding to a dedicated detection channel, and the resonance frequencies of different channels, Q Significant differences exist between the factors and near-field enhancement regions. When the mixed material is loaded onto the metasurface, the terahertz fingerprint characteristics of different components are quite different, and they will produce selective responses to specific frequency points of specific polarization channels. Such characteristics can be applied to the detection of trace amounts of biomolecules, analysis of chemical composition, or precise identification of environmental pollutants.

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