Dual-mode singularity sensing system based on phase transition

Abstract

This invention relates to a dual-mode singularity sensing system based on phase jump, comprising a sensing module composed of alternating layers of hyperbolic metamaterials and isotropic first dielectric layers. The sensing module exhibits a continuous-domain bound-state phenomenon when incident light propagates, and this continuous-domain bound-state phenomenon includes the ability to split into a pair of reflecting phase singularities with opposite topological charges. This invention extends singularity sensing technology from single-mode to dual-mode, enabling independent two-step measurements and exhibiting higher robustness to environmental perturbations.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a dual-mode singularity sensing system based on phase transition. Background Technology

[0002] With the continuous advancement of technology, sensor technology is becoming increasingly widespread and important in various fields. Traditional sensors have made significant progress in detection accuracy, sensitivity, and response speed. A phase singularity is a specific point in parameter space that possesses characteristics such as phase transitions and topological charges. A key advantage of using singularities to fabricate sensors is their ultra-high sensitivity. For example, in optical sensors, the singularity effect can significantly improve the detection capability of light signals, thereby achieving more accurate spectral analysis. However, traditional single-mode singularity sensing has the following drawbacks:

[0003] 1. Single-mode singularity sensing has limited effective space and is difficult to cover a large sensing area;

[0004] 2. Single-mode singularity sensing has a limited range of modes and can typically only detect a single type of parameter, making it difficult to achieve multiple independent measurements and is also greatly affected by complex environments.

[0005] 3. Single-mode singularities are more sensitive to angular perturbations, resulting in poor signal stability and robustness.

[0006] Therefore, with the application of singularity technology in optical sensors, single-mode singularity sensing can no longer meet the requirements. Dual-mode singularity sensing has significant advantages in multi-parameter detection and environmental adaptability. However, because singularities cause the system to respond sensitively to external perturbations, and the sensitivity increases with the order of the singularity, realizing dual-mode singularity sensing technology faces complex challenges in structural design, material dispersion characteristics, and parameter control. Furthermore, it is sensitive to environmental perturbations and noise.

[0007] Most existing dual-mode sensing methods employ elliptic polarization, which is based on the amplitude and phase difference between transverse electric (TE) and transverse magnetic (TM) waves. Although ellipticized light has two orthogonal polarizations, in previous studies, the TE and TM components were often non-decoupled; that is, existing dual-mode sensing actually corresponds to single-mode sensing. Furthermore, the existence of singularities mainly depends on the TM component, while the TE component of ellipticized light contributes almost nothing to the sensing process. To improve this approach, new strategies are necessary. Summary of the Invention

[0008] To address the aforementioned issues, this invention provides a dual-mode singularity sensing system based on phase transition, which extends singularity sensing technology from a single mode to a dual mode, enabling independent two-step measurement and exhibiting higher robustness to environmental disturbances.

[0009] The present invention is achieved through the following scheme: a dual-mode singularity sensing system based on phase jump, including a sensing module, which is composed of several hyperbolic metamaterial layers and several isotropic first dielectric layers stacked alternately. The sensing module satisfies the condition that it has a continuous domain bound state phenomenon when incident light is propagated, and the continuous domain bound state phenomenon includes the ability to split into a pair of reflecting phase singularities with opposite topological charges.

[0010] A further improvement of the dual-mode singularity sensing system based on phase jump of the present invention is that the hyperbolic metamaterial layer is composed of several composite unit layers stacked together, wherein the composite unit layer includes a second dielectric layer, a graphene layer and a metal layer stacked sequentially.

[0011] A further improvement of the dual-mode singularity sensing system based on phase transition of the present invention is that: the first dielectric layer is made of beryllium oxide and the second dielectric layer is made of gallium arsenide.

[0012] A further improvement of the dual-mode singularity sensing system based on phase transition of the present invention is that the metal layer is selected as indium tin oxide.

[0013] A further improvement of the dual-mode singularity sensing system based on phase jump of the present invention is that it further includes an infrared source for emitting the incident light to the sensing module at the frequency corresponding to any of the reflected phase singularities, and an infrared detector for monitoring the phase change of the sensing module and emitting a feedback signal when a phase jump is detected.

[0014] A further improvement of the dual-mode singularity sensing system based on phase transition of the present invention is that it also includes an incident layer superimposed on the surface of the sensing module, which is used to allow incident light to enter and protect the sensing module.

[0015] A further improvement of the dual-mode singularity sensing system based on phase transition of the present invention is that the incident layer is selected from a silver layer.

[0016] This invention applies the phase-jump theory of singularities obtained from BIC splitting to singularity sensing, which can extend singularity sensing technology from a single mode to a dual mode. Dual-mode singularity sensing based on phase-jump can achieve two independent measurements in a simple structure. Dual-mode singularity sensing based on phase-jump has higher robustness to environmental perturbations. Even with minor manufacturing errors, it does not affect the sensitivity and resolution of the sensing system, greatly reducing the manufacturing difficulty of the sensor. Attached Figure Description

[0017] Figure 1 A schematic diagram of the photon Weyl node line semi-metallic platform in the sensing module is shown.

[0018] Figure 2A schematic diagram of the surface states of the two drum surfaces in the photonic dual Weyl node ring of the sensing module is shown.

[0019] Figure 3 The transverse electric wave phase diagram is shown when the sensing module receives incident light at different incident angles.

[0020] Figure 4 This illustrates the effect of E when the sensing module receives incident light in both TE and TM modes. f A schematic diagram comparing the phase evolution at the singularity of the perturbation. Detailed Implementation

[0021] Most existing dual-mode sensors employ elliptic polarization, a method based on the amplitude and phase difference between transverse electric (TE) and transverse magnetic (TM) waves. Although ellipticized light has two orthogonal polarizations, the existence of its singularity depends primarily on the TM component, while the TE component contributes almost nothing to the sensing process. In other words, existing dual-mode sensing essentially corresponds to single-mode sensing. However, previous research shows that the TE and TM components are often non-decoupled; therefore, a new strategy is necessary.

[0022] Recent advances in non-Hermitian physics and topological photonics in condensed matter physics have made bound states in the continuum (BIC) and phase singularities a hot topic. BICs are localized states existing in the continuous spectrum, possessing properties such as no radiative loss, high quality factor, and topological protection. In some systems, BICs can be split into a pair of reflecting phase singularities with opposite topological charges by introducing absorption loss or radiative splitting. Based on the topological properties of BICs and singularities, high quality factor optical cavities and highly robust metamaterials have been designed. Furthermore, due to their topological protection, singularities exhibit excellent robustness and highly sensitive detection performance, effectively reducing fabrication errors and improving sensor sensitivity and resolution, leading to their widespread application in sensing technology, information processing, and wireless power transmission.

[0023] Based on the above, this invention proposes a novel dual-mode singularity sensing system based on phase-jumping. First, this invention theoretically studies how to divide a BIC (Block Component Index) into two reflecting phase singularities with opposite topological charges by adjusting absorption and radiation losses. Second, based on the flexible and stable phase-jumping characteristics near the singularity supported by degenerate BICs, a dual-mode singularity sensing strategy is proposed. Finally, using the ion concentration in the electrolyte as an environmental perturbation, combined with the material properties of the sensing module, the sensing characteristics of phase-jumping near the singularity are intuitively demonstrated through calculation results. The system proposed in this invention provides a new approach to achieving wireless sensing near phase-jumping singularities. Furthermore, the method of splitting a BIC into multiple singularities is expected to significantly expand the sensing space and increase the number of measurements in principle. The following specific embodiments, in conjunction with the accompanying drawings, further illustrate this dual-mode singularity sensing system based on phase-jumping.

[0024] See Figure 1 As shown, Figure 1 A schematic diagram of the photonic Weyl node line semi-metallic platform in the sensing module is shown. A dual-mode singularity sensing system based on phase-jumping includes a sensing module, which utilizes a one-dimensional photonic crystal (AB). N This one-dimensional photonic crystal (AB) N It is composed of N (a natural number greater than 1) hyperbolic metamaterial (HMM) layers A and N isotropic first dielectric layers B, stacked alternately. Specifically, the hyperbolic metamaterial layer A is composed of S (a natural number greater than 1) composite unit layers CGD, which can be represented as (CGD). S In this composite unit layer (CGD), C represents the second dielectric layer, G represents the graphene layer, and D represents the metal layer. The selection of materials for each layer and the determination of the number of layers S in the CGD depend on the actual sensing requirements of the sensing system, but the final CGD should be guaranteed to meet certain requirements. S It is a hyperbolic metamaterial and should meet the material properties of hyperbolic metamaterials. In this embodiment, the second dielectric layer C is gallium arsenide (GaAs) with a refractive index n. C ≈3.48). The metal layer D is made of indium tin oxide (ITO) because it has low loss in actual use and its dielectric constant ε is relatively low. D The value is negative, satisfying the metallic properties. Furthermore, the material of the first dielectric layer B can be determined in conjunction with the second dielectric layer C. In this embodiment, the first dielectric layer B is beryllium oxide (BeO) (its refractive index n...). B ≈1.708), such as Figure 1 As shown in Figures (a) and (d), Figure (a) illustrates a one-dimensional photonic crystal (AB) oriented at an angle θ. NAn incident light is emitted, and the operating frequency of the incident light is assumed to be ω = 2πf = 2π·288THz (where the temperature T = 300K). Figure (d) shows that in the state shown in Figure (a), the first dielectric layer B and the second dielectric layer C have weak dispersion near the operating frequency of interest, 288THz, which is closer to the actual working environment and facilitates subsequent calculation verification.

[0025] The following uses the incident light in Figure (a) as the calculation background to verify that the above (CGD)S structure can be equivalent to a hyperbolic metamaterial. The verification method is as follows:

[0026] The dielectric constant ε of the metal layer D is calculated using the following Drude model. D Describe:

[0027]

[0028] Where: ε ∞ Expressed as the high-frequency dielectric constant, ε ∞ =3.9; i represents the imaginary part; ω pD Represented as plasma frequency, considering Should Represented as the reduced Planck constant γ D Expressed as the damping frequency, under lossless conditions, considering In the event of damage, consider

[0029] The surface conductivity σ of graphene layer G G The inner component σ can be used intra and interband component σ inte To describe using the sum:

[0030]

[0031] Where: k B =1.380649×10^ (-23) J / K represents the Boltzmann constant; τ represents the relaxation rate. E f Represented as Fermi energy, v f Let v be the Fermi velocity of the electron. f ≈10 6 m / s, where n represents the carrier density adjusted by electrostatic doping, E f The carrier density n can be flexibly modulated by adjusting it through electrostatic doping.

[0032] Consider the three terms on the right side of the above formula (2) as the conductivity σ G The three parts, then the above formula (2) can be simplified to σG =σ1+σ2+σ3, see further details Figure 1 As shown in Figure (c), this figure illustrates the conductivity σ when incident light enters the sensing module. G A comparison chart of the contributions of the three parts. The chart clearly shows that in E... f When the conductivity σ of the graphene layer G is greater than 0.4 eV, the surface conductivity σ is... G Almost all of it is contributed by σ1. Therefore, at this point, the conductivity can be further simplified to σ. G =σ1, that is, the above formula (2) can be simplified using a simplified model. To express.

[0033] According to the effective dielectric theory, the components of the equivalent dielectric constant tensor of hyperbolic metamaterial layer A in the x and y directions are:

[0034]

[0035] Where: ε C，D Let εC and εD represent the dielectric constants of the second dielectric layer C and the metal layer D, respectively; ε0 represents the vacuum dielectric constant; δ0 C，D δ represents the duty cycle of the second dielectric layer C and the metal layer D, respectively. C，D =d C，D / d, where d represents the cell thickness. C，D Let d represent the thicknesses of the second dielectric layer C and the metal layer D, respectively, where d = d C +d D In this embodiment, the thicknesses of the hyperbolic metamaterial layer A, the first dielectric layer B, the second dielectric layer C, and the metal layer D are respectively selected as d. A =1210nm, d B =2696nm, d C =44nm, d D =11nm, while the number of stacked layers of the composite unit layer CGD is S=22, which is the number of periods of the HMM.

[0036] The σ calculated using formula (2) G Substituting into formula (3), the components of the equivalent dielectric constant tensor of the hyperbolic metamaterial layer A in the x and y directions can be calculated, while the component ε in the z direction... ⊥ The calculations described above are existing technology and will not be elaborated upon here. Through the above calculations, the relationship between each component of the equivalent dielectric constant tensor and frequency variation can be obtained, as detailed below. Figure 1 As shown in Figure (b), it is clear from the figure that the (CGD) S The structure in the 230THz to 300THz frequency band can be equivalent to HMM(ε) ∥ ε ⊥<0).

[0037] In this embodiment, the hyperbolic metamaterial layer A and the first dielectric layer B are stacked N times = 20. Therefore, this one-dimensional photonic crystal (AB) N It can also be represented as a superlattice [(CGD)] 22 B] 20 Considering Figure 1 (a) Figure 1 An additional thickness d is added in front of the incident surface of the 3D photonic crystal. E If the silver layer is 20 nm thick, then this is a one-dimensional photonic crystal (AB). N Represented as a superlattice E[(CGD)] 22 B] 20 The dielectric constant ε of the metal layer E is determined using the Drude model of formula (1). E To describe, as follows:

[0038]

[0039] Where: ε ∞ Expressed as the high-frequency dielectric constant, ε ∞ =4.09; i represents the imaginary part; ω pE Represented as plasma frequency, considering Should Represented as the reduced Planck constant γ E Expressed as the damping frequency, under lossless conditions, considering In the event of damage, consider

[0040] Based on the above structure E[(CGD)] 22 B] 20 The material properties of the sensing module enable it to exhibit the BIC phenomenon during incident light propagation, and this BIC phenomenon includes the ability to split into a pair of reflecting phase singularities with opposite topological charges. See details... Figure 2 As shown, Figure 2 A schematic diagram of the surface states of the two drum-shaped surfaces of the photonic dual Weyl node ring in the sensing module is shown. Figure 2 Figure (a) shows the superlattice E[(CGD)]. 22 B] 20 The theoretical reflection phase diagram in TE mode, (c) shows the superlattice E[(CGD)] 22 B] 20 The theoretical reflection phase diagram in TM mode. As can be seen from Figure (a), the BIC phenomenon exists when propagating incident light in TE mode, and theoretically, singularities corresponding to +1 and -1 topological charges can be separated. and singularity Similarly, as can be seen from Figure (c), the incident light propagating in TM mode exhibits the BIC phenomenon, and theoretically, singularities corresponding to +1 and -1 topological charges can be separated. and singularity Where: f0 represents the frequency, denoted as k ρ0 Radial wave vector, k0 represents the wave vector in the air.

[0041] Further, see Figure 2 Figure (b) shows the phase at specific incident angles near each singularity. As the frequency changes, the TE mode exhibits a similar phase jump around 291.6 THz, while the TM mode shows a similar phase jump around 288.8 THz. Considering the extreme sensitivity of such drastic phase changes to environmental disturbances such as refractive index, molecular concentration, and temperature, this provides a solid foundation for an ultra-high sensitivity sensing scheme. In fact, in traditional sensing schemes, the TE and TM modes are often coupled; therefore, the starting point in the TM mode must also be considered. In this embodiment, the different evolutions of the two modes determine that the sensing scheme can operate within a TE-TM reflection phase extension space. Implemented in, such as Figure 2 As shown in Figure (d) in the table.

[0042] To achieve detection, the aforementioned sensing system also requires an infrared source and an infrared detector. (See [link / reference]). Figure 4 As shown in Figure (a), the sensing system includes, in addition to the sensing module 11, an infrared source 20 for emitting incident light r1 to the sensing module 11 at the frequency corresponding to any reflection phase singularity, and an infrared detector 30 for monitoring the phase change of the sensing module 11 and emitting a feedback signal when a phase jump is detected. Preferably, an incident layer 12 is also superimposed on the surface of the sensing module 11 for allowing the incident light r1 to enter and the reflected light f1 to exit, and for protecting the sensing module 11. In this embodiment, the incident layer 12 is a silver layer.

[0043] In summary, by applying the phase-jump theory of singularities obtained from BIC splitting to singularity sensing, singularity sensing technology can be extended from single-mode to dual-mode. Dual-mode singularity sensing based on phase-jump can achieve two independent measurements in a simple structure. Compared to the single-mode scheme shown by a single line in Figure (b), this dual-mode scheme corresponds to a wider state space and allows for more system states. This characteristic provides a new direction for further improving the sensitivity of singularity sensing. Furthermore, dual-mode singularity sensing based on phase-jump exhibits higher robustness and sensitivity to environmental perturbations. The robustness and sensitivity of dual-mode singularity sensing are verified from two perspectives below:

[0044] On the one hand, robustness and sensitivity are verified by observing the phase evolution near the singularity after emitting incident light at different incident angles. (See also...) Figure 3 As shown, Figure 3 The transverse electrical wave phase diagram is shown when the sensing module receives incident light at different incident angles. For example... Figure 3 As shown in Figure (a), this figure illustrates the phase evolution near singularity A. It can be observed that for smaller incident angles, such as θ = 51.5° and θ = 51.7°, the phase exhibits a distinct falling edge. As the angle increases, the linewidth of the falling edge gradually decreases to zero (corresponding to the singularity), forming a step-like transition. Therefore, the location of the singularity can be determined simply by changing the incident angle. Furthermore, a significant phase change exists over a wide range of incident angles θ ∈ [52°, 60°]. Further... Figure 3 As shown in Figure (b), this figure illustrates the phase evolution near singularity B. It can be observed that the phenomenon is opposite to that at singularity A, but the pattern of change is similar: as the incident angle increases, the linewidth of the falling edge gradually increases from zero; the larger the angle, the more pronounced the falling edge. Based on this, it is shown that singularity A and singularity B... They have different topological charges. At the same time, there is a huge phase change in a wide range of incident angles θ∈[23°, 31.5°].

[0045] A common problem with traditional singularity-based sensors is their low accuracy at the incident angle, with sensitivity decreasing rapidly as the incident angle deviates. In contrast, the sensing system in this proposal is based on a singularity supported by surface states. As demonstrated above, both TE and TM modes exhibit significant phase transitions over a wide range of incident angles. Therefore, this proposed sensing system not only achieves a true dual-mode singularity but also demonstrates high robustness and sensitivity in both modes.

[0046] On the other hand, by applying environmental perturbations to change the Fermi energy E of graphene f To verify robustness and sensitivity, the phase evolution near the singularity is observed. Based on the above theoretical model, an experimental scheme is designed, assuming a superlattice E[(CGD)]. 22 B] 20 Immersed in electrolyte as a concentration sensor. See details. Figure 4 As shown, Figure 4 This illustrates the effect of E when the sensing module receives incident light in both TE and TM modes. f A schematic diagram comparing the phase evolution at the singularity of the perturbation. (See diagram below.) Figure 4 As shown in Figure (a), the concentration of ion 41 in electrolyte 40 is selected as an environmental disturbance to change the Fermi energy E of graphene. f Infrared source 20 emits incident light r1 in two modes. Among them,

[0047] First mode m1: corresponds to the singularity The incident angle θ = 31°, the frequency f = 277.2 THz, and the incident light r1 is in TE mode.

[0048] Second mode m2: corresponds to the singularity The incident angle θ = 43.9°, the frequency f = 287.6 THz, and the incident light r1 is in TM mode.

[0049] The phase transitions corresponding to the two modes are as follows: Figure 4 As shown in Figures (b) and (c), the reflection phase varies with E in both modes. f Response to changes Figure 4 As shown in Figure (d), the sensitivity of both modes is close to 10. 4 The order of magnitude of deg / RIU. Because the ion concentration is on the order of 10... -3 mol·L -1 The order-of-magnitude change resulted in a response of 10. 2 The actual sensitivity is likely higher, given that the value is meV.

[0050] Furthermore, assuming a response bandwidth and a fixed confidence interval. like Figure 4 As shown in Figure (d), taking the case indicated by the dark asterisk as an example, its corresponding Fermi energy E f =0.9185eV. In the first mode m1, the response region is... The corresponding Fermi energy range is E f ∈[0.91807, 0.91880]eV; Under the second mode m2, the response region is The corresponding Fermi energy range is E f ∈[0.91822, 0.91880]eV. Considering both modes simultaneously, a more precise Fermi energy range can be determined as E. f ∈[0.91822, 0.91800]eV. Then, project the specific nodes onto the response curve associated with the confidence interval to the environmental variable (i.e., Fermi energy E). f On the axis of ), it is clear from figure (d) that for a fixed region of environmental variables, the bimodal response bandwidth is wider, while it is clear from figures (b) and (c) that the Fermi energy E is within a certain range. f Under disturbances, significant phase jumps are observed, which, from another perspective, verifies that the sensing system of this scheme has high robustness.

[0051] Of course, in practical applications, environmental disturbances are not limited to changing the Fermi energy; they can be extended to other forms, such as adding a dielectric layer outside the sensing module to change the refractive index. Regardless of the form of environmental disturbance, the ultimate conclusion is that the sensing system of this solution has excellent robustness. Even with minor manufacturing errors, the sensitivity and resolution of the sensing system are not affected, greatly reducing the difficulty of sensor manufacturing.

[0052] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. Those skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention shall be defined by the appended claims.

Claims

1. A dual-mode singularity sensing system based on phase transition, characterized in that: The sensor module is composed of several hyperbolic metamaterial layers and several isotropic first dielectric layers stacked alternately. The sensor module satisfies the condition of having a continuous domain bound state phenomenon when incident light is propagated, and the continuous domain bound state phenomenon includes the ability to split into a pair of reflection phase singularities with opposite topological charges.

2. The dual-mode singularity sensing system based on phase transition as described in claim 1, characterized in that: The hyperbolic metamaterial layer is composed of several composite unit layers stacked together, and the composite unit layer includes a second dielectric layer, a graphene layer and a metal layer stacked sequentially.

3. The dual-mode singularity sensing system based on phase transition as described in claim 2, characterized in that: The first dielectric layer is made of beryllium oxide, and the second dielectric layer is made of gallium arsenide.

4. The dual-mode singularity sensing system based on phase transition as described in claim 2, characterized in that: The metal layer is made of indium tin oxide.

5. The dual-mode singularity sensing system based on phase transition as described in claim 1, characterized in that: It also includes an infrared source for emitting the incident light to the sensing module at a frequency corresponding to any of the said reflection phase singularities, and an infrared detector for monitoring the phase changes of the sensing module and emitting a feedback signal when a phase jump is detected.

6. The dual-mode singularity sensing system based on phase transition as described in claim 1, characterized in that: It also includes an incident layer superimposed on the surface of the sensing module, which is used to allow incident light to enter and protect the sensing module.

7. The dual-mode singularity sensing system based on phase transition as described in claim 6, characterized in that: The incident layer is selected from silver.

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