Method for regulating and controlling Q value of optical resonance peak and application

Abstract

The method comprises the following steps: 1) acquiring inherent attribute parameters of a target system and / or an environment refractive index change value delta n; the target system is a multi-resonant coupling system and / or an asymmetric BIC system; (2) constructing an equation based on the environment refractive index change value delta n and / or the obtained inherent attribute parameters in the step (1); when the target system is a multi-resonance coupling system, a relational expression between the resonance peak Qr value and the environment refractive index change value delta n is built, the invention belongs to the field of optical physics, and particularly relates to an optical resonance peak Q value regulation and control method and application of the method. When the target system is an asymmetric BIC system, according to a radiation quality factor law formula of the asymmetric BIC system; and 3) performing calculation based on the formula 1 and the formula 2, and adjusting the environment refractive index change value delta n or changing the asymmetric factor alpha according to the calculation result of the Qr value and the adjustment purpose so as to regulate and control the Qr value. According to the invention, the Qr value can be controlled through the change of the environment refractive index.

Description

Technical Field

[0001] The present invention belongs to the field of optical physics, and in particular relates to an optical resonance peak Q value control method and application. Background Art

[0002] Optical physics is the science of the interaction between light and matter. As an electromagnetic wave, the propagation, reflection, refraction, diffraction and scattering of light are all affected by the properties of matter. These basic physical processes form the basis for the operation of optical sensing devices and systems. The wave nature of light, especially its frequency and wavelength, can be used to accurately measure the optical properties of matter, including refractive index, absorption coefficient and scattering characteristics.

[0003] Optical sensors use the physical properties of light to detect and quantify changes in external factors. They are widely used in environmental monitoring, chemical analysis, materials science, and biomedical engineering. Compared with traditional electrochemical sensors, optical sensors have higher sensitivity, faster response time, and better anti-interference ability. With the development of micro-nano processing technology, the size of optical sensors continues to shrink and the integration continues to increase, making it possible to realize portable and low-cost sensing devices.

[0004] Biosensing technology is an extension of the application of optical sensors in the biological field. The identification and detection of biological molecules are crucial for disease diagnosis, environmental monitoring, food safety and other fields. However, traditional biological detection methods often rely on complex labeling processes and large analytical equipment, which limits their scope of application and convenience. For example, the traditional plasmon SPR configuration is the most commonly used commercial biosensing platform, but its complex oblique-incident prism coupling and detection optical path system make the equipment large and expensive, making it difficult to apply and integrate on a large scale. Therefore, the development of a new type of biosensing technology that can achieve label-free, high-sensitivity, fast response and portable detection has become an urgent need in scientific research and industry.

[0005] At present, the visible / near-infrared optical metasurface biosensor is a universal label-free biosensor, which is widely used in scientific research and daily life. Although label-free can be achieved, it still needs to be combined with supercontinuum light sources, large spectrometers and other equipment to complete optical sensing tests, resulting in a complex and large test system that is not portable and universal. In addition, in order to improve the sensing performance, the current mainstream research direction is to make the resonance peak Q value (i.e., Qr value) higher (line width narrower) through complex design and precision processing. This further leads to problems such as increased preparation costs and greater testing difficulty, and requires more precise and expensive testing equipment, which deviates from the goal of practical and integrated optical biosensor systems. In recent years, the concept of non-spectral imaging biosensor combined with high-Q optical metasurfaces has been proposed, allowing people to see the possibility of further integration of optical biosensor systems. However, in the sensing process, the problem of matching the dynamic high-Q narrow-linewidth resonance peak with the static specific wavelength light source is always prominent. The problem mainly comes from the following three sources: 1. The contradiction that the illumination source frequency is fixed but the resonant frequency moves with the object being measured can easily cause frequency mismatch, resulting in irregular response; 2. The high-Q optical metasurface has low robustness to preparation defects, which further causes resonant frequency shift and mismatch. 3. The illumination source bandwidth does not match the resonant bandwidth. For example, the high-Q resonant bandwidth is usually 1-5nm, while the bandwidth of the usual illumination source is above 5nm, which will cause the response to fail when the high-Q resonant frequency moves; the above-mentioned frequency and bandwidth mismatch problem not only reduces the reliability of the imaging signal, but also causes the chip preparation to be highly dependent on high-precision processing equipment, which greatly restricts the practicality and versatility of integrated imaging optical sensors. In view of the above problems, there are few solutions in the prior art. At present, the only relatively effective method is to use the bound state in the continuous domain (BIC) to design and prepare a series of two-dimensional BIC metasurface array structures with different asymmetric symmetry coefficients to perform pixel scanning of the Q value from low to high (here referred to as the "sweep Q" solution), so as to meet the sensor working, there is always a resonance peak of the array that can be well matched with the light source band. For example, CN202280010383.3 has a sensor component with an optical metasurface film. As mentioned above, this technical solution requires the design of a specific sensor pixel array and a metasurface array, etc., and realizes the Qr value adjustment through the construction of a complex array. For example, CN202110970414.7 all-medium metasurface refractive index sensor and its preparation method, which also realizes the improvement of sensor performance through a dielectric metasurface structure unit array. The overall design process is relatively complex, the versatility is very limited, and the performance is also significantly limited by the array. In addition, in the frequency shift sensing mechanism, an expensive narrowband tunable light source is required to align with the high Q value signal.This "Q-value scanning" scheme based on the two-dimensional BIC metasurface further increases the reliance on high-precision preparation, making the processing steps more complicated, further increasing the cost, and making it more difficult to apply on a large scale.

[0006] To this end, the present invention aims to achieve efficient regulation of the resonance peak Qr value for any existing metasurface array structure, mainly by regulating the environment outside the system, while greatly improving the performance of the optical sensor and realizing a truly integrated and practical high-Q value optical metasurface biosensor system. Summary of the invention

[0007] In order to solve the problem of frequency and bandwidth mismatch between sensors and light sources caused by high Q values ​​in actual applications of current optical sensing systems, especially optical biosensor systems, the design, modulation and correction are difficult and costly, and the equipment is large in size and inconvenient to use. It is usually necessary to specifically design and prepare a series of two-dimensional metasurface array structures with different asymmetric symmetry coefficients and scan Q to select a metasurface array structure with a higher matching degree to achieve the problem of Qr value regulation, or to use a high-precision adjustable narrowband light source and a high-resolution spectrometer, which leads to a sharp increase in system cost, and the existing technical methods are difficult to be effectively and universally applied to the design, modulation and correction of optical biosensors. The present invention provides a method for regulating the optical resonance peak Qr value, and the application of the method in optical sensing systems and / or optical sensing devices, especially biosensor systems and / or biosensor devices.

[0008] The main purpose of the present invention is:

[0009] 1. Ability to efficiently control the Qr value by changing the ambient refractive index;

[0010] Second, the Qr value is highly controllable, and the Qr value of the target system can be increased or decreased according to demand to approach the optimal Qr value or even completely coincide with the optimal Qr value to achieve a critical coupling state;

[0011] 3. It can be effectively applied to all existing optical sensing systems and / or optical sensing devices, and realize an integrated high-Q value optical sensing system.

[0012] To achieve the above objectives, the present invention adopts the following technical solutions.

[0013] A method for adjusting the peak Q value of optical resonance.

[0014] The method comprises:

[0015] 1) Obtaining the intrinsic property parameters of the target system and / or the environmental refractive index change value Δn;

[0016] The target system is a multi-resonance coupling system and / or an asymmetric BIC system;

[0017] The multi-resonance coupling system comprises a resonator 1 and a resonator 2, the natural frequency of the resonator 1 redshifts as Δn increases, while the natural frequency of the resonator 2 does not change with Δn, the frequency of the resonator 1 in a zero decoupling state is equal to the frequency of the resonator 2, and the natural loss of the resonator 1 does not change with Δn, while the natural loss of the resonator 2 increases as Δn increases;

[0018] The asymmetric BIC system comprises two nanoparticle metasurfaces with different diameters / heights / materials / spatial displacements;

[0019] 2) constructing the associated Qr value based on the environmental refractive index change value Δn and / or the obtained intrinsic property parameters in step 1); when the target system is a multi-resonant coupling system, the obtained intrinsic property parameters include: the upper energy branch frequency ω of the coupling system, the initial attenuation coefficient γ′2 of the resonator 2 in the zero decoupling state, the coupling strength g between the resonator 1 and the resonator 2, and the Rabi splitting Ω R , the sensitivity S1 of the eigenfrequency of resonator 1 to the change value Δn of the environmental refractive index, the sensitivity S2 of the eigenfrequency of resonator 2 to the change value Δn of the environmental refractive index, the natural frequency ω1 of resonator 1, the natural frequency ω2 of resonator 2, the non-radiative attenuation coefficient γ n ;

[0020] The relationship between the resonance peak Qr value and the ambient refractive index change value Δn is constructed as follows:

[0021] Formula 1:

[0022] Where: Q r is the radiation quality factor, i.e. the resonance peak Q r value, ω is the upper energy branch frequency of the strong coupling system, γ′2 is the initial attenuation coefficient of resonator 2 in the zero decoupling state, g is the coupling strength between resonator 1 and resonator 2, Ω R is the Rabi splitting, Δn is the change in the ambient refractive index, S1 is the sensitivity of the eigenfrequency of resonator 1 to the change in the ambient refractive index Δn, S2 is the sensitivity of the eigenfrequency of resonator 2 to the change in the ambient refractive index Δn, i is a pure imaginary number and is defined as i 2 =-1, ω1 is the natural frequency of resonator 1, ω2 is the natural frequency of resonator 2, γ n is the non-radiative attenuation coefficient;

[0023] When the target system is an asymmetric BIC system, the acquired intrinsic property parameters include: an asymmetry factor α;

[0024] According to the following formula, the radiation quality factor of the asymmetric BIC system is:

[0025] Formula 2: Q r =a+bα -2 ;

[0026] Where: Q r is the radiation quality factor, i.e. the resonance peak Q r value, α is the asymmetry factor, and both a and b are represented by at least two points. r Substitute α into the calculated fitting result;

[0027] 3) Based on equation 1 and equation 2 in step 2) above:

[0028] When the target system is a multi-resonance coupling system, the intrinsic property parameters are substituted into Formula 1 for calculation, and the ambient refractive index change value Δn is adjusted according to the calculation result of the Qr value and the adjustment purpose to achieve the regulation of the Qr value;

[0029] The method of adjusting the environmental refractive index change value Δn includes adjusting and / or replacing the liquid system or the atmospheric environment in which the target multi-resonance coupling system is located;

[0030] When the target system is an asymmetric BIC system, the nanoparticles of the asymmetric BIC system are selectively modified according to the purpose of regulation, and the asymmetric factor α is changed to achieve the regulation of the Qr value;

[0031] When the target system has the characteristics of a multi-resonant coupling system and an asymmetric BIC system at the same time, at least one of the above methods is used to change the environmental refractive index change value Δn and / or the asymmetry factor α to achieve the regulation of the Qr value.

[0032] As a preference,

[0033] Step 2) The relationship between the resonance peak Qr value and the environmental refractive index change value Δn is constructed in combination with the critical coupling mechanism, and Formula 1 is combined with the following Formula 3, the correction formula for the coupling strength between the resonator 1 and the resonator 2, and Formula 4, the conversion coefficient calculation formula;

[0034] Formula 3: g n =g×Δn(S1-S2)

[0035] In formula 3: g n is the result of the coupling strength g between resonator 1 and resonator 2 after being corrected by the change value Δn of the environmental refractive index, Δn is the change value of the environmental refractive index, S1 is the sensitivity of the eigenfrequency of resonator 1 to the change value Δn of the environmental refractive index, and S2 is the sensitivity of the eigenfrequency of resonator 2 to the change value Δn of the environmental refractive index;

[0036] Formula 4: m = 5Δn(S1-S2)

[0037] Wherein: m is the conversion coefficient of the difference in the change of the intrinsic attenuation coefficient passively generated by the introduction of the difference in the change of the intrinsic frequency generated by resonator 1 and resonator 2 during the sensing process of the target multi-resonance coupling system, Δn is the change value of the ambient refractive index, S1 is the sensitivity of the intrinsic frequency of resonator 1 to the change value Δn of the ambient refractive index, and S2 is the sensitivity of the intrinsic frequency of resonator 2 to the change value Δn of the ambient refractive index.

[0038] As a preference,

[0039] Formula 1 is combined with Formula 3 and Formula 4 to obtain the following Formula 5:

[0040] Formula 5:

[0041] Where: Q r is the radiation quality factor, i.e., the resonance peak Qr value, ω is the upper energy branch frequency of the strong coupling system, γ′2 is the initial attenuation coefficient of resonator 2 in the zero decoupling state, m is the conversion coefficient of the difference in the intrinsic attenuation coefficient change passively generated by the introduction of the difference in the intrinsic frequency change generated by resonator 1 and resonator 2 in the sensing process of the target multi-resonance coupling system, and g n is the coupling strength g between resonators 1 and 2 after being corrected by the change in the ambient refractive index Δn, Ω R is the Rabi splitting, Δn is the change in the ambient refractive index, S1 is the sensitivity of the eigenfrequency of resonator 1 to the change in the ambient refractive index Δn, S2 is the sensitivity of the eigenfrequency of resonator 2 to the change in the ambient refractive index Δn, i is a pure imaginary number and is defined as i 2 =-1, ω1 is the natural frequency of resonator 1, ω2 is the natural frequency of resonator 2, γ n is the non-radiative attenuation coefficient.

[0042] As a preference,

[0043] When the target system is an asymmetric BIC system or contains the characteristics of an asymmetric BIC system, the Qr value is regulated by formula 2 after the regulation demand is determined according to the resonance peak absorbance expression of formula 6;

[0044] Formula 6:

[0045] Where: Abs is the absorbance, x is the maximum absorption value of the system and is substituted into 1 for calculation, Q r is the radiation quality factor, Q n is the non-radiative quality factor, ω is the frequency of any resonator in the zero decoupling state, ω r is the natural oscillation frequency of the system when there is no loss;

[0046] This is done when the target system contains asymmetric nanostructures NP-a and NP-b;

[0047] The nanostructure NP-a and the nanostructure NP-b have different structural widths and / or structural radii and / or structural heights and / or relative spatial positions, wherein the structural width and / or structural radius and / or structural height of the nanostructure NP-a are greater than the structural width and / or structural radius and / or structural height of the nanostructure NP-b;

[0048] The selective modification process is to modify the surface of the nanostructure NP-a and / or the nanostructure NP-b to form a local refractive index change, which can be deposited oxide or biomolecule modification.

[0049] As a preference,

[0050] The local refractive index change and radiation quality factor Q formed by the surface modification of the nanostructure NP-a r Negatively correlated;

[0051] The local refractive index change and radiation quality factor Q formed by the surface modification of the nanostructure NP-b r There is a positive correlation.

[0052] Application of an optical resonance peak Q value control method,

[0053] The method is used for modulation and / or design and / or correction of an optical sensing system and / or an optical sensing device.

[0054] As a preference,

[0055] The optical sensing system and / or optical sensing device includes a biosensing system and / or a biosensing device.

[0056] For the technical solution of the present invention, the most critical is the construction of formula 1 and the application of formula 2. In the traditional Q-switching system, it is achieved by changing the microscopic physical structure of the system, and the implementation process is a series of trial and error processes, and the microstructure system with the optimal Qr value is finally reached in the trial and error process. However, for the technical solution of the present invention, the solution based on formula 1 is to effectively convert the real part change of the refractive index into the imaginary part change of the resonant frequency in the visible / near-infrared band, thereby adjusting the Qr value, and jumping out of the traditional sensing idea that the environmental refractive index change value Δn only corresponds to the real part change value of the resonant frequency. Formula 2 adjusts the Qr value by selectively modifying the asymmetric structure and changing the local environmental refractive index. It is different from the conventional sensing process, in which the nanostructure is uniformly modified without selectivity, but based on the relationship between the Qr value and the asymmetric factor α in formula 2, by selecting one of the nanostructures in the binary asymmetric structure for modification, the Qr value can be effectively changed in the sensing process. Through formula 1 or 2, and combined with the correction of formulas 3-4 and 6, Qr quickly approaches Qn. Since the system absorption reaches 100% when Qr=Qn, the system absorption will be greatly enhanced in the process of Qr rapidly approaching Qn, thereby achieving effective change of Qr value through environmental refractive index and making a great change in the intensity of system feedback signal, thereby completing an integrated platform that is highly compatible with various light sources.

[0057] As for formula 1, it is derived through a series of derivations. First, based on The basic formula of is derived, and the eigensolution in the strong coupling system of the double oscillator (i.e., containing oscillator 1 and oscillator 2) is derived using the 2×2 Hamiltonian algorithm as follows:

[0058] Formula S1:

[0059] Where: H is the Hamiltonian, ω1 is the natural frequency of oscillator 1, ω2 is the natural frequency of oscillator 2, γ1 is the decay rate of oscillator 1, γ2 is the decay rate of oscillator 2, i is a pure imaginary number and is defined as i 2 =-1, g is the coupling strength between resonator 1 and resonator 2.

[0060] The above formula S1 algorithm can be used to obtain the intrinsic-energy relationship as follows:

[0061] Formula S2:

[0062] Where: ± is the eigenfrequency of the double resonator system, ω1 is the natural frequency of resonator 1, ω2 is the natural frequency of resonator 2, γ1 is the decay rate of resonator 1, γ2 is the decay rate of resonator 2, i is a pure imaginary number and is defined as i2 =-1, g is the coupling strength between resonator 1 and resonator 2.

[0063] When ω1=ω2, the zero decoupling position is reached, and the Rabi splitting is obtained as follows:

[0064] Formula S3:

[0065] Where: Ω R is the Rabi splitting, γ1 is the decay rate of resonator 1, γ2 is the decay rate of resonator 2, and g is the coupling strength between resonators 1 and 2.

[0066] When the Rabi splitting satisfies the condition greater than 0, a strongly coupled system can be realized. At this time, we introduce the environmental refractive index change value Δn, so that the system enters the non-zero decoupling state (ω1>ω2) from the zero decoupling state. Then this will introduce frequency shifts in both energy levels, namely the frequency change △ω1 of resonator 1 and the frequency change △ω2 of resonator 2. At this time, formula S3 will be expanded to the following formula group of formulas S4 to S7:

[0067] Formula S4: Δω1=S1Δn; Δω2=S2Δn;

[0068] Formula S5: ΔΔω=Δn(S1-S2);

[0069] Formula S6:

[0070] Formula S7: ΔΔγ=Δγ1-Δγ2;

[0071] In the above formula group: Δω1 is the frequency change of resonator 1, Δω2 is the frequency change of resonator 2, Δn is the change value of the ambient refractive index, S1 is the sensitivity of the eigenfrequency of resonator 1 to the change value Δn of the ambient refractive index, S2 is the sensitivity of the eigenfrequency of resonator 2 to the change value Δn of the ambient refractive index, ΔΔω is the difference in the frequency change between resonator 1 and resonator 2, g is the coupling strength between resonator 1 and resonator 2, and i is a pure imaginary number and is defined as i 2 =-1,Ω R is Rabi splitting, γ′1 is the initial attenuation coefficient of resonator 1 in the zero decoupling state, γ′2 is the initial attenuation coefficient of resonator 2 in the zero decoupling state, ΔΔγ is the difference in the change of attenuation rate between resonator 1 and resonator 2, Δγ1 is the change of attenuation rate of resonator 1, and Δγ2 is the change of attenuation rate of resonator 2.

[0072] Therefore, the difference in the eigenfrequency in the strongly coupled system caused by the change in the ambient refractive index is brought into the Rabi splitting formula, and the above perturbation formula S6 is obtained. At this time, we assume that in this strongly coupled system, ω1 is very sensitive to the ambient refractive index change value Δn, while ω2 is very insensitive to the ambient refractive index change value Δn, that is, S1>>S2. At this time, ΔΔγ can be derived as the following formulas S8 and S9:

[0073] Formula S8:

[0074] Formula S9:

[0075] In the above equations S8 and S9: ΔΔγ is the difference in the decay rate change between resonator 1 and resonator 2, g is the coupling strength between resonator 1 and resonator 2, Ω R is the Rabi splitting, ΔΔω is the difference in frequency change between resonator 1 and resonator 2, γ′1 is the initial attenuation coefficient of resonator 1 under zero decoupling state, γ′2 is the initial attenuation coefficient of resonator 2 under zero decoupling state, ω1 is the natural frequency of resonator 1, ω2 is the natural frequency of resonator 2, i is a pure imaginary number and is defined as i 2 =-1. Since ΔΔω and ω1-ω2 are both positive numbers, according to formula S8, ΔΔγ must be a negative number. If for resonator 1, it has produced significant ΔΔω, then its Δγ1 is very small, even close to 0, which means that for resonator 2 with extremely small Δω2, its Δγ2 will inevitably become significantly larger, that is, the attenuation coefficient will increase significantly. In this way, the change in the real part of the refractive index is converted into the change in the imaginary part of the resonant frequency, that is, Δn is linked to Δγ. In summary, in the strongly coupled system of dual resonators, as long as the following two conditions are met, the change in the real part of the ambient refractive index can be converted into a considerable change in the imaginary part of the resonant frequency, thereby obtaining the following formulas S10 and S11:

[0076] Formula S10: ΔΔω>>0(Δω1>>Δω2);

[0077] Formula S11: ΔΔγ<<0 (Δγ1<<Δγ2);

[0078] In the formula: ΔΔω is the difference in frequency change between resonator 1 and resonator 2, Δω1 is the frequency change of resonator 1, Δω2 is the frequency change of resonator 2, ΔΔγ is the difference in attenuation rate change between resonator 1 and resonator 2, Δγ1 is the attenuation rate change of resonator 1, and Δγ2 is the attenuation rate change of resonator 2.

[0079] Based on this condition, we design a specific nano-optical structure to achieve our goal. Furthermore, since the total attenuation coefficient γ is actually composed of the radiation attenuation coefficient γ rand the non-radiative attenuation coefficient γ n It consists of two parts, as shown in formula S12:

[0080] Formula S12: γ=γ r +γ n ;

[0081] Where: γ is the total attenuation coefficient, γ r is the radiation attenuation coefficient, γ n is the non-radiative attenuation coefficient.

[0082] Among them, γ n It is mainly determined by the material that makes up the nanostructure and is not affected by the change in the ambient refractive index. Therefore, in the above-mentioned strong coupling system, the change in the attenuation coefficient caused by the change in the ambient refractive index Δn is mainly the radiation attenuation coefficient γ r At this time, according to conditional equation S11, we assume that the attenuation coefficient change Δγ1 of resonator 1 is zero, then for the attenuation coefficient change of resonator 2, we can obtain the following equations S13 and S14:

[0083] Formula S13: γ′2+Δγ2=γ r +γ n ;

[0084] Formula S14: γ r =γ′2-ΔΔγ-γ n ;

[0085] Where: γ′2 is the initial attenuation coefficient of resonator 2 in the zero decoupling state, Δγ2 is the change in the attenuation rate of resonator 2, and γ r is the radiation attenuation coefficient, γ n is the non-radiative attenuation coefficient, and ΔΔγ is the difference in the attenuation rate change between resonator 1 and resonator 2.

[0086] According to the relationship between attenuation coefficient and quality factor Q Formula 14 can be converted into the expression S15 of the radiation Q value: Formula S15:

[0087] Where: Q r is the radiation quality factor, i.e. the resonance peak Q r value, ω is the energy branch frequency of the strong coupling system, γ′2 is the initial attenuation coefficient of resonator 2 in the zero decoupling state, ΔΔγ is the difference in the attenuation rate change between resonator 1 and resonator 2, γ n is the non-radiative attenuation coefficient.

[0088] From this we can write Δn and Q r The direct relationship formula S16, that is, the formula 1 of the present invention:

[0089] Formula S16 (Formula 1):

[0090] Where: Q r is the radiation quality factor, i.e. the resonance peak Q r value, ω is the upper energy branch frequency of the strong coupling system, γ′2 is the initial attenuation coefficient of resonator 2 in the zero decoupling state, g is the coupling strength between resonator 1 and resonator 2, Ω R is the Rabi splitting, Δn is the change in the ambient refractive index, S1 is the sensitivity of the eigenfrequency of resonator 1 to the change in the ambient refractive index Δn, S2 is the sensitivity of the eigenfrequency of resonator 2 to the change in the ambient refractive index Δn, i is a pure imaginary number and is defined as i 2 =-1, ω1 is the natural frequency of resonator 1, ω2 is the natural frequency of resonator 2, γ n is the non-radiative attenuation coefficient.

[0091] This formula is the new Q-switching mechanism (resonance peak Qr value adjustment mechanism) proposed by the present invention, which can convert the change of the real part of the refractive index into the change of the resonant Q value (resonance peak Qr value). However, the change of the Q value alone mainly brings about the change of the signal bandwidth. In order to make the signal change more significant, we need to combine the refractive index Q-switching mechanism with the critical coupling mechanism, combined with the following formula S17 (Formula 3):

[0092] Formula S17 (Formula 3):

[0093] Where: Abs is the absorbance, x is the maximum absorption value of the system and is substituted into 1 for calculation, Q r is the radiation quality factor, Q n is the non-radiative quality factor, ω is the frequency of any resonator in the zero decoupling state, ω r is the natural oscillation frequency of the system when there is no loss.

[0094] When the radiation quality factor Q r and non-radiative quality factor Q n When the absorption is equal, the system will reach the maximum absorption x, which is the critical coupling. Here we set x to 1. Combining formulas S16 and S17, we can achieve significant changes in signal bandwidth and intensity at the same time by refractive index Q-switching near the critical coupling state, which is referred to as the near critical coupling Q-switched sensing mechanism (Q-switched near critical coupling, QSCC).

[0095] To make the calculation more realistic, we introduce two corrections. 1: The coupling strength g should also be related to the refractive index change Δn, g n=g×Δn(S1-S2); 2: Due to the existence of other radiation leakage channels in practical applications, ΔΔγ should not be able to fully participate in the QSCC sensing process. Therefore, we set a ΔΔγ conversion coefficient m, which represents the part of the attenuation coefficient change that participates in the QSCC sensing mechanism. Moreover, the conversion coefficient increases with the increase of Δn: m=5Δn(S1-S2). Therefore, the modified refractive index Q-switching formula is formula S18 (formula 4):

[0096] Formula S18 (Formula 4):

[0097] Where: Q r is the radiation quality factor, i.e. the resonance peak Q r value, ω is the upper energy branch frequency of the strong coupling system, γ′2 is the initial attenuation coefficient of resonator 2 in the zero decoupling state, m is the conversion coefficient of the difference in the intrinsic attenuation coefficient change passively generated by the introduction of the difference in the intrinsic frequency change generated by resonator 1 and resonator 2 during the sensing process in the target multi-resonance coupling system, and g n is the coupling strength g between resonators 1 and 2 after being corrected by the change in the ambient refractive index Δn. The correction formula is g n =g×Δn(S1-S2),Ω R is the Rabi splitting, Δn is the change in the ambient refractive index, S1 is the sensitivity of the eigenfrequency of resonator 1 to the change in the ambient refractive index Δn, S2 is the sensitivity of the eigenfrequency of resonator 2 to the change in the ambient refractive index Δn, i is a pure imaginary number and is defined as i 2 =-1, ω1 is the natural frequency of resonator 1, ω2 is the natural frequency of resonator 2, γ n is the non-radiative attenuation coefficient.

[0098] By further modifying the above formula S17 (Formula 3), the calculated result will be closer to the actual value and have a very high confidence level.

[0099] The beneficial effects of the present invention are:

[0100] The present invention realizes the control of the Qr value by a very simple way of changing the ambient refractive index, and can increase or decrease the Qr value of the target system according to needs to approach the optimal Qr value or even completely coincide with the optimal Qr value, and the theoretical calculation results have a very high confidence level. Moreover, since the technical solution of the present invention is not limited to any material and / or structure, it can be effectively applied to the modulation, design and correction of all existing optical sensing systems and / or optical sensing devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0101] Figure 1 The structural parameters of the 3D plasmon BIC metasurface designed by FDTD simulation in Example 1;

[0102] Figure 2 The three-dimensional spectrum result obtained by changing the ambient refractive index based on the FDTD simulation design in Example 1;

[0103] Figure 3 The reflectivity characterization results at different glycerol concentrations in Example 1;

[0104] Figure 4 is a graph showing the relationship between peak intensity and wavelength variation in Example 1;

[0105] Figure 5 The Qr value and the half-maximum width FWHM in Example 1 are trend graphs of changes with the refractive index;

[0106] Figure 6 is a trend diagram of the Qr value changing with the refractive index based on Formula 1 in Example 1;

[0107] Figure 7 is a graph showing the variation trend of the absorption intensity with the refractive index based on Formula 1 in Example 1;

[0108] Figure 8 is a trend diagram of the Qr value versus refractive index based on Formula 5 in Example 1;

[0109] Fig. 9 is a graph showing the variation trend of the absorption intensity with the refractive index based on Formula 5 in Example 1;

[0110] Fig.10 It is a schematic diagram of the physical model of near-critical coupling Q-switched biosensor based on a strong coupling system of the present invention;

[0111] Fig.11 Schematic diagram of the quasi-BIC supersurface on the gold substrate in Example 2;

[0112] Fig.12 is a graph showing the relationship between absorption intensity and wavelength under critical coupling conditions in Example 2;

[0113] Fig.13 is a graph showing the relationship between absorption intensity and wavelength after critical coupling is broken in Example 2;

[0114] Fig.14 is a graph showing the relationship between absorption intensity and wavelength under critical coupling conditions after the surface structure of NP-a is changed in Example 2;

[0115] Fig.15 is a graph showing the relationship between absorption intensity and wavelength when the critical coupling is broken after the surface structure of NP-a is changed in Example 2;

[0116] Fig.16 is a graph showing the relationship between absorption intensity and wavelength under critical coupling conditions after the surface structure of NP-b is changed in Example 2;

[0117] Fig.17 is a graph showing the relationship between absorption intensity and wavelength when the critical coupling is broken after the surface structure of NP-b is changed in Example 2;

[0118] Fig.18 is a relationship diagram between the environmental refractive index and the resonance wave in Example 2;

[0119] Fig.19 To change the relationship between the refractive index difference and the absorption intensity between the two nanoparticles in Example 2 Figure 1 ;

[0120] Fig. 20 To change the relationship between the refractive index difference and the absorption intensity between the two nanoparticles in Example 2 Figure 2 ;

[0121] Fig.21 Schematic diagram of the preparation process of the 3D plasmonic BIC supersurface designed in Example 1;

[0122] Fig. 22 Schematic diagram of the sensing performance of the three-dimensional BIC metasurface simulated body in Example 3;

[0123] Fig.23 Schematic diagram of the three-dimensional BIC metasurface sensing module based on the QSCC sensing mechanism in Example 3 and its surface sensing performance in the VIS band. DETAILED DESCRIPTION

[0124] The present invention is further described in detail below in conjunction with specific embodiments and the accompanying drawings. A person of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0125] In the description of the present invention, it should be understood that the terms "thickness", "upper", "lower", "horizontal", "top", "bottom", "inner", "outer", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, "multiple" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined, and "several" means one or more.

[0126] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0127] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods known to those skilled in the art.

[0128] Example 1

[0129] This example is intended to verify Formula 1 and Formulas 3 to 6 of the present invention.

[0130] First, a new type of 3D plasmonic BIC metasurface was designed using FDTD simulation and its performance in sensing was calculated. Its structural parameters are as follows: Figure 1 As shown, the diameter of gold particles 1 and 2 in the metasurface is D1=D2=320nm, the depth of gold particles 1 and 2 is Z1=60nm, Z2=200nm, the period P=800nm, the substrate is resin (resin, refractive index 1.56); the gold upper layer material is titanium dioxide TiO2, with a refractive index of 2.2 and a thickness of 80nm. The thickness of the gold layer is 50nm, and the material refractive index is fitted using the Johnson & Christy material library data. By changing the ambient refractive index in FDTD, we get Figure 2 The three-dimensional spectrum results. It can be seen that qBIC1 is still dominated by frequency shift, and it redshifts as the refractive index increases, while its peak intensity does not change much, which meets condition one (Δw1>>0, Δγ1≈0). However, qBIC2 shows that as the refractive index increases, the peak intensity increases significantly, the half-peak width becomes wider, and the frequency shift is very small, which meets condition two (Δw2≈0, Δγ2>>0). Therefore, qBIC2 in the simulation intuitively verifies the QSCC sensing mechanism.

[0131] Through the above simulation calculations, further verification is carried out in specific experiments.

[0132] Through the nanoimprint binary anodized aluminum process, we prepared the above-designed 3D plasmonic BIC metasurface, which has the same microscopic physical structure characteristics. The specific preparation process is as follows (process as Fig.21 As shown, this example takes 800nm ​​period preparation as an example):

[0133] First, a nickel film with periodic nanorods (T = 800 nm) was used to test the -2 The aluminum sheet was imprinted at a pressure of 3 for 3 minutes to form a nanodot array with a spacing of 800nm ​​on the surface of the aluminum sheet. The imprinted aluminum sheet was then anodized at 320V at 30°C for 2h in a mixed solution (4g citric acid, 200mL ethanol, 200mL H2O and 10mL 0.1wt% H3PO4) to obtain aligned nanopores (a holes). The aluminum sheet was immersed in a 5wt% H3PO4 solution for 2 hours to enlarge these a holes. An ALD system was then used to deposit a thin layer of TiO2 inside the A holes to protect them from chemical corrosion. ALD was performed at 150°C with a cycle time of 0.5s C12H28O4Ti, 8s N2 purge, 0.1s H2O, 8s N2 purge, and 70 cycles. The top surface of the BP-AAO template was then milled using an ion milling system (IM4000plus) to ensure that the b holes were fully opened. The PMMA solution was coated on the surface of the BP-AAO template, and the unoxidized aluminum sheet was removed using a mixed solution (1.5wt% CuCl2 and 53.2% HCl). The PMMA layer was then dissolved in acetone. Finally, the BP-AAO template was immersed in a 0.1M NaOH solution at room temperature for 30 minutes to generate new holes (holes b) at the quadruple junctions of hole a. The BP-AAO template was then transferred to a silicon wafer in water.

[0134] The silicon wafer with the BP-AAO template was placed in an inductively coupled plasma etching system (Leuven ICP, HAASRODE-E200A) and etched for 20 seconds using a mixed gas of CF4 and SF6 at 20°C and 8mT VAT. Ion beam tilt milling was then used to remove the barrier layer of the a-hole. A 10nm thick Cr layer was then deposited as a sacrificial layer using physical vapor deposition (PVD). After peeling off the BP-AAO template, two layers of Cr particles can be observed. A second ICP etching was then performed using the same gas recipe, but the etching time was 24s to produce the 3D silicon-based nanostructure. A 50nm Au film was deposited on the 3D silicon-based nanostructure, and then coated with UV-cured NOA83 resin. The 3D nanostructure was peeled off from the silicon wafer using a direct lift-off method. Finally, a TiO2 layer was deposited by PVD to form a 3D BIC metasurface, and the coupling conditions were controlled by changing the TiO2 thickness.

[0135] The diameters of nanoparticles 1 and 2 in the metasurface are D1=D2=320nm, the depths of nanoparticles 1 and 2 are Z1=60nm, Z2=200nm, and the period P=800nm. The environmental refractive index Δn is changed by introducing different glycerol concentrations in the microfluidic system, and the reflectivity is characterized. The results are shown in FIG. Figure 3As shown. Figure 3 The spectrum obtained from the experimental test is consistent with Figure 2 The simulation spectrum is highly consistent. qBIC1 mainly shows frequency shift, which redshifts as the refractive index increases, while its peak intensity does not change much, meeting condition one (Δw1>>0, Δγ1≈0). qBIC2 shows that as the refractive index increases, the peak intensity increases significantly, the half-peak width becomes wider, and the frequency shift is very small, meeting condition two (Δw2≈0, Δγ2>>0).

[0136] Based on the experimental characterization, the peak intensity and wavelength variation of qBIC2 were extracted and obtained as follows: Figure 4 As shown in the result diagram, it can be seen that the peak intensity increases sharply as the refractive index increases, but the wavelength does not change significantly (<3nm). Its absolute intensity refractive index sensitivity reaches 561% / RIU, and its relative intensity refractive index sensitivity reaches 1500% / RIU. Based on the experimental characterization, the Qr value and half-peak width FWHM of qBIC2 extracted with the refractive index change trend are as follows Figure 5 As shown. As the refractive index increases, it decays rapidly and approaches Q n value, that is, it is close to the critical coupling state. At the same time, the FWHM gradually becomes wider, reflecting the increase in radiation loss.

[0137] In addition, based on the following equations 1 and 6:

[0138] Formula 1:

[0139] Where: Q r is the radiation quality factor, i.e. the resonance peak Q r value, ω is the upper energy branch frequency of the strong coupling system, γ′2 is the initial attenuation coefficient of resonator 2 in the zero decoupling state, g is the coupling strength between resonator 1 and resonator 2, Ω R is the Rabi splitting, Δn is the change in the ambient refractive index, S1 is the sensitivity of the eigenfrequency of resonator 1 to the change in the ambient refractive index Δn, S2 is the sensitivity of the eigenfrequency of resonator 2 to the change in the ambient refractive index Δn, i is a pure imaginary number and is defined as i 2 =-1, ω1 is the natural frequency of resonator 1, ω2 is the natural frequency of resonator 2, γ n is the non-radiative attenuation coefficient;

[0140] Formula 6:

[0141] Where: Abs is the absorbance, x is the maximum absorption value of the system and is substituted into 1 for calculation, Q r is the radiation quality factor, Q n is the non-radiative quality factor, ω is the frequency of any resonator in the zero decoupling state, ω ris the natural oscillation frequency of the system when there is no loss;

[0142] Substitute the experimental parameters: γ n =2.5meV,ω=97.8meV,g=27.2meV,Ω R =46meV, S1 = 300meV / RIU, S2 = 0meV / RIU, x = 1, γ′2 are 2.5, 2.7, 2.9, 3.1, 3.3, 3.5meV respectively (corresponding to the initial decay rate γ r0 is 0, 0.2, 0.4, 0.6, 0.6, 0.8 and 1.0; when γ r0 = 0 means that the initial state of the system is the BIC state). Figure 6 and Figure 7 Results shown.

[0143] It can be found that Q r As the refractive index increases, it decays rapidly. However, the smaller γ r0 Make Q r The curve rises as a whole, with a higher initial Q when Δn = 0 r At the same time, the absorption peak intensity increases rapidly with the increase of the refractive index change value, and when Q r Approach Q n , it approaches saturation. And, the smaller γ r0 This makes the initial absorption intensity lower, resulting in faster intensity changes and a larger intensity change range. Therefore, by introducing a radiation loss suppression mechanism, such as BIC, QSCC sensing in a strongly coupled system will have better performance.

[0144] Based on the above results and Figure 5 By comparison, it can be found that the Qr value change trend is Figure 1 The results show that the refractive index of the light emitting diodes (LEDs) decreases rapidly with the increase of the refractive index, and the critical coupling state is finally achieved, which verifies the validity of Formula 1 of the present invention.

[0145] On this basis, we further modify equation 1 with equation 3 and equation 4 to obtain equation 5:

[0146] Formula 3: g n =g×Δn(S1-S2)

[0147] In formula 3: g n is the result of the coupling strength g between resonator 1 and resonator 2 after being corrected by the change value Δn of the environmental refractive index, Δn is the change value of the environmental refractive index, S1 is the sensitivity of the eigenfrequency of resonator 1 to the change value Δn of the environmental refractive index, and S2 is the sensitivity of the eigenfrequency of resonator 2 to the change value Δn of the environmental refractive index;

[0148] Formula 4: m = 5Δn(S1-S2)

[0149] In Formula 4, m is the conversion coefficient of the difference in the change of the intrinsic attenuation coefficient of the target multi-resonance coupling system passively generated by the introduction of the difference in the change of the intrinsic frequency generated by resonator 1 and resonator 2 during the sensing process, Δn is the change value of the ambient refractive index, S1 is the sensitivity of the intrinsic frequency of resonator 1 to the change value Δn of the ambient refractive index, and s2 is the sensitivity of the intrinsic frequency of resonator 2 to the change value Δn of the ambient refractive index;

[0150] Formula 5:

[0151] In formula 5: Q r is the radiation quality factor, i.e., the resonance peak Qr value, ω is the upper energy branch frequency of the strong coupling system, γ′2 is the initial attenuation coefficient of resonator 2 in the zero decoupling state, m is the conversion coefficient of the difference in the intrinsic attenuation coefficient change passively generated by the introduction of the difference in the intrinsic frequency change generated by resonator 1 and resonator 2 in the sensing process of the target multi-resonance coupling system, m=5Δn(S1-S2), g n is the coupling strength g between resonators 1 and 2 after being corrected by the change in the ambient refractive index Δn. The correction formula is g n =g×Δn(S1-S2),Ω R is the Rabi splitting, Δn is the change in the ambient refractive index, S1 is the sensitivity of the eigenfrequency of resonator 1 to the change in the ambient refractive index Δn, s2 is the sensitivity of the eigenfrequency of resonator 2 to the change in the ambient refractive index Δn, i is a pure imaginary number and is defined as i 2 =-1, ω1 is the natural frequency of resonator 1, ω2 is the natural frequency of resonator 2, γ n is the non-radiative attenuation coefficient.

[0152] Substitute the above parameters and get Figure 8 and Fig. 9 The overall Qr value and absorption intensity change with the refractive index. Figure 6 and Figure 7 Similar. But the refractive index changes to 10 -2 RIU level, closer to Figure 5 The performance in the actual experiment shown in the figure proves that the modified Q-switching formula (Formula 5) is more in line with reality and has a higher degree of confidence. Fig.10 As shown: The strongly coupled system converts the refractive index Δn into Q r The value changes, and then combined with the critical coupling system, Q rThe value change will be effectively converted into a significant change in the resonance peak intensity, and during this process, the frequency remains basically unchanged. At the same time, the introduction of BIC can effectively optimize the Q-switched sensing effect.

[0153] Example 2

[0154] This example is intended to verify Formula 2 of the present invention.

[0155] In an asymmetric quasi-BIC system, the radiation resonance peak Qr value can be effectively controlled by changing the coupling between the two resonant cavities. Fig.11 The QSCC sensing performance of the nanoparticles was studied on the gold substrate shown in a (period 600nm, ambient refractive index 1.33 of water, nanoparticle material is gold, height 100nm). The gold substrate contains two kinds of metasurfaces with different diameters of nanoparticles. When the diameters of the nanoparticles are d a =150nm / d b =130nm, its characteristics are as follows Fig.12 As shown, on a gold substrate, perfect absorption (Q r =Q n ). When the overall environmental refractive index changes, since the critical coupling condition does not change, the resonance only shifts the peak wavelength, and the peak intensity does not change. a =150nm,d b =100nm, if Fig.13 The critical coupling condition shown is broken (Q r >Q n ), the absorption is lower, but changing the overall ambient refractive index still results in only a frequency shift. This confirms that under bulk sensing conditions, the coupling between the two nanoparticles is unchanged, that is, the Q in the quasi-BIC system r In this case, the volume refractive index change Δn is only connected to Δw and not to Δγ.

[0156] However, if Fig.11 As shown in b, when only SiO2 layer is coated on NP-a, Fig.14 and Fig.15 In the above figure, the absorption intensity of the resonance is significantly reduced. This strongly indicates that the intrinsic coupling between the two nanoparticles has changed, thereby changing the Qr value. Due to the large difference in the polarizability of NP-a and NP-b, the quasi-BIC system will move away from the BIC, increasing the asymmetry factor α. This phenomenon can be explained by the radiation quality factor law of the asymmetric BIC metasurface, Equation 2: Q r =a+bα -2 , changing the refractive index near only one of the nanoparticles will cause α to increase (decrease), thus making Q rSince the metasurface with gold film as substrate forms a one-port system, and since the absorbance of the system is determined by the following

[0157] Formula 6: When Q r When it decreases (increases), the absorption intensity will change significantly.

[0158] In addition, if Fig.11 c in and Fig.16 and Fig.17 As shown in Figure 2, by adding a SiO2 layer on NP-b, the polarizability difference between the two nanoparticles first becomes smaller, close to the BIC point, α is suppressed, and the Qr value increases. Therefore, it begins to enter the over-coupling state, causing the absorption to drop rapidly, and then after reaching the maximum value, Q r (Qr value) decreases, and it approaches the critical coupling state again, causing the absorption to increase again. Fig.17 In, with Q r The increase (Q r n ), the system moves from the undercoupled state to the critical coupling state, and the absorption increases.

[0159] Since there is inherent material loss in the asymmetric BIC metasurface based on plasmons, in order to eliminate its influence, we further demonstrated the QSCC mechanism using a BIC metasurface based on dielectric materials (substrate is gold, period is 600nm, ambient refractive index is 1.33 of water, nanoparticle material is TiO2, height is 100nm). Fig.18 In the case of Q, the resonant wavelength is red-shifted as the overall ambient refractive index changes, but the peak absorption changes very little. r The slight increase in can be attributed to the change in the effective refractive index of the resonator. Fig.19 In the figure, when a SiO2 layer is added on NP-a, the refractive index difference between the two nanoparticles becomes larger (α becomes larger), and the system moves from overcoupling to critical coupling, resulting in increased absorption. Fig. 20 The situation is just the opposite. Adding a SiO2 layer on NP-b suppresses α, making Q r increases, away from the critical coupling, while the absorption decreases.

[0160] This also confirms the effectiveness of the regular formula of formula 2 of the present invention.

[0161] Therefore, the surface refractive index of two different nanoparticles can be controlled separately through the selectively modified quasi-BIC system, which once again proves the effectiveness of the QSCC sensing mechanism.

[0162] Example 3

[0163] ​Based on the aforementioned Examples 1 and 2, while verifying the effectiveness of the control method, it is also actually verified that it has good application prospects in the design of optical sensing systems and / or optical sensing devices. This Example 3 further experimentally extends the versatility of the control method of the present invention to the range from visible light to short-wave infrared, and demonstrates better performance than existing metasurface biosensors.

[0164] like Fig. 22 As shown, Fig. 22 Figure a shows the simulated bulk sensing performance of a 3D BIC metasurface with lattice periods of 400nm, 600nm, and 800nm. The bulk environment refractive index varies between 1.33 and 1.37. The simulation evaluates how different lattice periods affect the sensing performance of the 3D BIC metasurface in response to changes in the bulk refractive index. Figure b shows the volume and surface sensing performance experiments of the 3D BIC metasurface with lattice periods of 400nm, 600nm, and 800nm. In the experiment, the bulk refractive index can be changed by adjusting the concentration of the glycerol solution from 0 to 40%. For the change in the surface refractive index, atomic layer deposition (ALD) of an aluminum oxide layer with a step size of 5nm was used to simulate the binding of biomolecules. The experimental data provides insight into the actual performance and sensitivity of the 3DBIC metasurface for both bulk and surface sensing applications.

[0165] First, we experimentally prepared 3D BIC samples with periods of 400, 600 and 800 nm, respectively, to realize the QSCC sensing mechanism in the visible (~650nm), near-infrared (~940nm) and short-wave infrared (~1260nm) bands. As shown in the figure below, in the shaded area, whether it is by changing the overall environmental refractive index by changing the glycerol concentration or by changing the nanostructure surface refractive index by ALD deposition of aluminum oxide layer, the resonance peaks excited by the QSCC sensing mechanism show very good and significant peak intensity changes, as well as obvious line width broadening.

[0166] At the same time, the experimental and simulation results are also well consistent.

[0167] Such a mechanism also has the potential to be further used in the infrared band. Our highest Q value can reach 253 (central wavelength is 1265nm, line width is 5nm). For traditional sensing mechanisms, the signal response bandwidth is limited by the resonance peak line width. Therefore, under the same conditions, the narrow line width of the high Q value resonance peak will inevitably lead to a limited signal response bandwidth. Using the QSCC sensing mechanism, we can achieve a high Q value while obtaining a wider signal response bandwidth due to the adjustable resonance peak line width. Therefore, the high Q value metasurface sensor can be combined with a cheaper and miniaturized broadband filter to achieve a more integrated biosensing or imaging system.

[0168] as follows Fig.23 As shown, Fig.23 In the figure, a is a three-dimensional BIC metasurface sensing module based on the QSCC sensing mechanism, which has high bandwidth and frequency compatibility and can adapt to various light sources and photoelectric sensors. b is the surface sensing performance of QSCC in the VIS band. The solid line represents the spectral change with the increase of SiO2 layer thickness (0nm SiO2 as background, BG), and the filled pattern curve represents the illumination of light sources with bandwidths of 2, 10 and 25nm, centered at 640nm. c is the hyperspectral reconstructed image under illumination of light sources with bandwidths of 2, 10 and 25nm, and the corresponding line profile on the right. Scale bar 50 μm.

[0169] Based on a three-dimensional BIC metasurface with a lattice period of 400 nm, we have completed an integrated hyperspectral imaging system. Due to the unique properties of the QSCC sensing mechanism, its compatibility with various light sources is further revealed in the spectrometer-free hyperspectral imaging system. SiO2 strips with a thickness gradient of 10 to 30 nm were prepared by photolithography. The nanoscale morphology was reconstructed by irradiation with light sources of different bandwidths in water. Tunable narrow-band illumination (2 nm) of different wavelengths showed different gradient intensity patterns, with correct gradient nanostructure reconstruction at 640 nm. Broadband illumination (10 and 25 nm) in the 640 nm band can also effectively reconstruct the gradient morphology with obvious intensity differentiation, corresponding to SiO2 thickness of 10 to 30 nm. In addition, the system achieved a minimum vertical resolution of 3.5 nm and a minimum lateral resolution of 3 μm for SiO2. The device can integrate a maximum sensing unit density of 2.7 million (2.7×10 7 ) units / square centimeter, achieving and exceeding the current highest superstructure sensor density in the world, one million (1×10 7 ) units / square centimeter. In addition, our system is more integrated, and the sensor chip preparation is cheaper and more practical, which can bring greater potential and application value to the promotion of high-performance biosensors.

Claims

1. A method for controlling the peak Q value of optical resonance, characterized in that: The method comprises: 1) Obtaining the intrinsic property parameters of the target system and / or the environmental refractive index change value Δn; The target system is a multi-resonance coupling system and / or an asymmetric BIC system; The multi-resonance coupling system comprises a resonator 1 and a resonator 2, the natural frequency of the resonator 1 redshifts as Δn increases, while the natural frequency of the resonator 2 does not change with Δn, the frequency of the resonator 1 in a zero decoupling state is equal to the frequency of the resonator 2, and the natural loss of the resonator 1 does not change with Δn, while the natural loss of the resonator 2 increases as Δn increases; The asymmetric BIC system comprises two nanoparticle metasurfaces with different diameters / heights / materials / spatial displacements; 2) constructing the associated Qr value based on the environmental refractive index change value Δn and / or the intrinsic property parameters obtained in step 1); When the target system is a multi-resonant coupling system, the inherent property parameters obtained include: the upper branch frequency ω of the coupling system, the initial attenuation coefficient γ'2 of the resonator 2 in the zero decoupling state, the coupling strength g between the resonator 1 and the resonator 2, and the Rabi splitting Ω R , the sensitivity S1 of the eigenfrequency of resonator 1 to the change value Δn of the environmental refractive index, the sensitivity S2 of the eigenfrequency of resonator 2 to the change value Δn of the environmental refractive index, the natural frequency ω1 of resonator 1, the natural frequency ω2 of resonator 2, the non-radiative attenuation coefficient γ n ; The relationship between the resonance peak Qr value and the ambient refractive index change value Δn is constructed as follows: Formula 1: Where: Q r is the radiation quality factor, i.e. the resonance peak Q r value, ω is the upper energy branch frequency of the strong coupling system, γ'2 is the initial attenuation coefficient of resonator 2 in the zero decoupling state, g is the coupling strength between resonator 1 and resonator 2, Ω R is the Rabi splitting, Δn is the change in the ambient refractive index, S1 is the sensitivity of the eigenfrequency of resonator 1 to the change in the ambient refractive index Δn, S2 is the sensitivity of the eigenfrequency of resonator 2 to the change in the ambient refractive index Δn, i is a pure imaginary number and is defined as i 2 =-1, ω1 is the natural frequency of resonator 1, ω2 is the natural frequency of resonator 2, γ n is the non-radiative attenuation coefficient; When the target system is an asymmetric BIC system, the acquired intrinsic property parameters include: an asymmetry factor α; According to the following formula, the radiation quality factor of the asymmetric BIC system is: Formula 2: Q r =a+bα -2 ; Where: Q r is the radiation quality factor, i.e. the resonance peak Q r value, α is the asymmetry factor, and both a and b are represented by at least two points. r Substitute α into the calculated fitting result; 3) Based on equation 1 and equation 2 in step 2) above: When the target system is a multi-resonance coupling system, the intrinsic property parameters are substituted into Formula 1 for calculation, and the ambient refractive index change value Δn is adjusted according to the calculation result of the Qr value and the adjustment purpose to achieve the regulation of the Qr value; The method of adjusting the environmental refractive index change value Δn includes adjusting and / or replacing the liquid system or the atmospheric environment in which the target multi-resonance coupling system is located; When the target system is an asymmetric BIC system, the nanoparticles of the asymmetric BIC system are selectively modified according to the purpose of regulation, and the asymmetric factor α is changed to achieve the regulation of the Qr value; When the target system has the characteristics of a multi-resonant coupling system and an asymmetric BIC system at the same time, at least one of the above methods is used to change the environmental refractive index change value Δn and / or the asymmetry factor α to achieve the regulation of the Qr value.

2. The optical resonance peak Q value control method according to claim 1, characterized in that: Step 2) The relationship between the resonance peak Qr value and the environmental refractive index change value Δn is constructed in combination with the critical coupling mechanism, and Formula 1 is combined with the following Formula 3, the correction formula for the coupling strength between the resonator 1 and the resonator 2, and Formula 4, the conversion coefficient calculation formula; Formula 3: g n =g×Δn(S1-S2) In formula 3: g n is the result of the coupling strength g between resonator 1 and resonator 2 after being corrected by the change value Δn of the environmental refractive index, Δn is the change value of the environmental refractive index, S1 is the sensitivity of the eigenfrequency of resonator 1 to the change value Δn of the environmental refractive index, and S2 is the sensitivity of the eigenfrequency of resonator 2 to the change value Δn of the environmental refractive index; Formula 4: m = 5Δn(S1-S2) Wherein: m is the conversion coefficient of the difference in the change of the intrinsic attenuation coefficient passively generated by the introduction of the difference in the change of the intrinsic frequency generated by resonator 1 and resonator 2 during the sensing process of the target multi-resonance coupling system, Δn is the change value of the ambient refractive index, S1 is the sensitivity of the intrinsic frequency of resonator 1 to the change value Δn of the ambient refractive index, and S2 is the sensitivity of the intrinsic frequency of resonator 2 to the change value Δn of the ambient refractive index.

3. The optical resonance peak Q value control method according to claim 2, characterized in that: Formula 1 is combined with Formula 3 and Formula 4 to obtain the following Formula 5: Formula 5: Where: Q r is the radiation quality factor, i.e., the resonance peak Qr value, ω is the upper energy branch frequency of the strong coupling system, γ'2 is the initial attenuation coefficient of resonator 2 in the zero decoupling state, m is the conversion coefficient of the difference in the intrinsic attenuation coefficient change passively generated by the introduction of the difference in the intrinsic frequency change generated by resonator 1 and resonator 2 during the sensing process in the target multi-resonance coupling system, and g n is the coupling strength g between resonators 1 and 2 after being corrected by the change in the ambient refractive index Δn, Ω R is the Rabi splitting, Δn is the change in the ambient refractive index, S1 is the sensitivity of the eigenfrequency of resonator 1 to the change in the ambient refractive index Δn, S2 is the sensitivity of the eigenfrequency of resonator 2 to the change in the ambient refractive index Δn, i is a pure imaginary number and is defined as i 2 =-1, ω1 is the natural frequency of resonator 1, ω2 is the natural frequency of resonator 2, γ n is the non-radiative attenuation coefficient.

4. The optical resonance peak Q value control method according to claim 2, characterized in that: When the target system is an asymmetric BIC system or contains the characteristics of an asymmetric BIC system, the Qr value is regulated by formula 2 after the regulation demand is determined according to the resonance peak absorbance expression of formula 6; Formula 6: Where: Abs is the absorbance, x is the maximum absorption value of the system and is substituted into 1 for calculation, Q r is the radiation quality factor, Q n is the non-radiative quality factor, ω is the frequency of any resonator in the zero decoupling state, ω r is the natural oscillation frequency of the system when there is no loss; This is done when the target system contains asymmetric nanostructures NP-a and NP-b; The nanostructure NP-a and the nanostructure NP-b have different structural widths and / or structural radii and / or structural heights and / or spatial relative positions, wherein the structural width and / or structural radius and / or structural height of the nanostructure NP-a are greater than the structural width and / or structural radius and / or structural height of the nanostructure NP-b; The selective modification process is to modify the surface of the nanostructure NP-a and / or the nanostructure NP-b to form a local refractive index change.

5. The method for adjusting the optical resonance peak Q value according to claim 4, characterized in that: The local refractive index change and radiation quality factor Q formed by the surface modification of the nanostructure NP-a r Negatively correlated; The local refractive index change and radiation quality factor Q formed by the surface modification of the nanostructure NP-b r There is a positive correlation.

6. Use of the method according to any one of claims 1 to 5, characterized in that: The method is used for modulation and / or design and / or correction of an optical sensing system and / or an optical sensing device.

7. A use according to claim 6, characterized in that: The optical sensing system and / or the optical sensing device include a biological sensing system and / or a biological sensing device.

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