Single molecule optical signal enhancement method based on waveguide structure optimization

Abstract

The present application relates to the technical field of signal enhancement, and is a single-molecule light signal enhancement method based on waveguide structure optimization, which specifically comprises the following steps: performing multi-partition groove etching on the surface of a light guide layer, introducing a transverse isolation band, and collecting a set of waveguide structure parameters; dynamically adjusting groove depth and refractive index difference to obtain an energy concentration parameter; constructing a single-molecule anchoring site and a nano-limiting hole at the energy peak point of each partition unit to obtain a partitioned waveguide composite structure; under the irradiation of excitation light, light energy is excited to the single-mode area of the corresponding partition through the mode coupling mode controlled by the incident angle; obtaining enhanced light signal data; periodically detecting the partitioned waveguide composite structure, calculating the drift coefficient of the light intensity of each partition, and performing correction processing. The present application solves the problem in the prior art that signal cross interference and data analysis complexity increase due to the inability to ensure that each molecule is independently coupled to the enhanced light field.

Description

Technical Field

[0001] This invention relates to the field of signal enhancement technology, specifically a single-molecule optical signal enhancement method based on waveguide structure optimization. Background Technology

[0002] In the field of single-molecule detection technology, especially in waveguide-based optical signal enhancement methods, existing technologies face the problem of light field competition and energy redistribution in the coexistence of multiple molecules, which limits the accuracy and reliability of detection. When multiple fluorescent molecules coexist in the localized mode region on the waveguide surface with a spacing of less than 20 nanometers, they are in the same energy enhancement region. Due to the coupling saturation characteristics of the electromagnetic field, the light field energy will be non-uniformly distributed among the molecules, causing some molecules to preferentially occupy the energy-dense region, while the signals of other molecules are significantly suppressed, thus causing random enhancement and extinction of the output signal, destroying the uniqueness of single-molecule recognition. This light field "crowding effect" is a photon density competition phenomenon that cannot be solved by simple surface modification or concentration control, because its root cause lies in the lateral coupling and energy diffusion of the light field modes in the waveguide structure. Existing waveguides Designs often lack effective physical isolation mechanisms, making optical field interference between adjacent molecules unavoidable, especially in high-density molecular immobilization scenarios. Energy redistribution leads to signal fluctuations and increased background noise, further reducing the signal-to-noise ratio of the detection. In addition, traditional methods are insufficient in controlling the optical field mode, making it difficult to achieve precise energy localization, which makes it impossible to maintain the intensity of single-molecule excitation light stably, affecting the repeatability of long-term measurements. In biochemical reaction field applications, such as real-time molecular diagnostics or dynamic biological process monitoring, the accuracy of molecular immobilization is limited, and multi-molecule interference becomes the norm. Existing technologies cannot ensure that each molecule is independently coupled to the enhanced optical field, leading to signal cross-interference and increased complexity of data analysis. Therefore, a new method is needed to fundamentally solve the problems of optical field competition and energy redistribution in order to achieve stable, reliable, and unique single-molecule optical signal enhancement. Summary of the Invention

[0003] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0004] The technical problem to be solved by this invention is that in the prior art, the inability to ensure that each molecule is independently coupled to the enhanced optical field leads to signal cross-interference and increased complexity of data analysis. This invention proposes a single-molecule optical signal enhancement method based on waveguide structure optimization.

[0005] To achieve the above objectives, the technical solution of the single-molecule optical signal enhancement method based on waveguide structure optimization of the present invention includes the following steps: S1: A light guide layer is fabricated on a transparent substrate. Multi-zoned grooves are etched on the surface of the light guide layer to form multiple partition units. Lateral isolation strips are introduced between each partition to collect waveguide structure parameter sets. S2: Based on the dynamic adjustment of the groove depth and the refractive index difference of the upper surface covering layer within the partition unit, the light field mode is induced to form a single energy peak at the center of the partition unit, and the energy concentration parameter is obtained. S3: Based on the energy concentration parameter, single-molecule anchor points and nano-confined holes are constructed at the energy peak points of each partition unit. At the same time, the single molecules are matched one-to-one with the energy peak points to obtain a partitioned waveguide composite structure. S4: Place the partitioned waveguide composite structure under excitation light, and use incident angle control and mode coupling to excite the single-mode region of the corresponding partition. The spectral intensity of each partition unit is collected synchronously to obtain enhanced optical signal data; S5: Perform periodic detection on the partitioned waveguide composite structure, calculate the drift coefficient of the light intensity of each partition, and perform correction processing based on the drift coefficient.

[0006] Preferably, S1 includes: S11: Based on the refractive index of the transparent substrate material and target operating wavelength The light guide layer is prepared by chemical vapor deposition. S12: A periodic groove array is formed on the surface of the light guide layer by electron beam exposure and dry etching to obtain a light guide layer structure with a periodic groove array. S13: Isolation treatment is performed at the grooves in the periodic groove array to obtain a transverse isolation band. ; S14: Based on the transverse isolation zone, the energy density ratio of the local light intensity distribution function is calculated. Simultaneously, single-mode propagation verification and coupling suppression verification are performed. If the verification is successful, the output is a set of waveguide structure parameters.

[0007] Preferably, S2 includes: S21: Based on the waveguide structure parameter set, establish the longitudinal interference condition equation to obtain the depth ratio; S22: Based on the depth ratio and the refractive index of the light guide layer, the refractive index gradient distribution is designed by depositing a high refractive index film with a lateral gradient, and the refractive index distribution function of the upper surface cover layer is obtained.

[0008] S23: Based on the refractive index distribution function and depth ratio, the energy attenuation coefficient is obtained. ; Calculate the energy density distribution curve based on the energy attenuation coefficient to determine the energy peak location; S24: Based on the energy peak position and energy decay coefficient The ratio of light intensity at the center of the partition to that at the partition boundary is calculated, the stability of the energy peak is verified, and the verification result is output as an energy concentration parameter. .

[0009] Preferably, S3 includes: S31: Based on the energy density distribution curve, the coordinates of the single-molecule anchor positioning points are determined by the nano-positioning system, and the coordinates of all partitions are integrated to obtain the set of single-molecule anchor positioning point coordinates. S32: Based on the set of coordinates of single-molecule anchor points, chemical anchor points are constructed on the waveguide surface to obtain a chemical anchor positioning array.

[0010] S33: Based on the chemical anchor positioning array and energy attenuation coefficient, a vertical nano-confined hole is formed on the waveguide surface to obtain a nano-confined hole array concentric with the chemical anchor positioning point. S34: Based on a nano-confined hole array, a metal positioning island structure is formed at the bottom of the nano-confined holes; S35: Verification of single-molecule-optical field coupling through metal positioning island structure and chemical anchor positioning array; When the verification is successful, a single-molecule-optical-field composite unit is formed, resulting in the verified partitioned waveguide composite structure. If the verification fails, repeat this step.

[0011] Preferably, S4 includes: S41: Based on the partitioned waveguide composite structure, calculate the initial incident angle and set the polarization direction; S42: Calculate the effective mode propagation constant and energy coupling efficiency of each partition based on the incident angle, polarization direction and waveguide structure parameter set.

[0012] S43: Based on the effective mode propagation constant, energy coupling efficiency and partitioned waveguide composite structure, calculate the total optical field intensity distribution within the partition, and determine the single-molecule excitation intensity according to the total optical field intensity distribution within the partition. S44: Based on the single-molecule excitation intensity and the set of coordinates of the single-molecule anchor points in S3. Calculate the single-molecule emission spectral intensity of each partition to form a partition spectral matrix; S45: Obtain the reference spectrum in the unenhanced state. , partition spectral matrix Compared with reference spectrum The comparison yielded the enhancement ratio for each partition. Synchronous output of average enhancement factor And make a judgment; when If a significant enhancement change is detected in the waveguide structure, step S5 is executed, and the enhanced optical signal data is output simultaneously. when If the waveguide structure does not show any enhancement change, repeat step S4.

[0013] Preferably, S5 includes: S51: Based on partitioned spectral matrix Record the initial light intensity of each partition and generate a light intensity reference matrix. ; S52: Obtain real-time detected light intensity Based on real-time detection of light intensity and light intensity reference matrix Calculate the light intensity drift coefficient And make a judgment; when When, it indicates enhancement; when When, it indicates decay; when If the value is ≥0.05, it is determined that energy drift has occurred; Simultaneously based on the partitioned spectral matrix Light intensity reference matrix Calculate the correlation coefficient of light intensity between adjacent partitions And based on the light intensity drift coefficient Make a judgment; When the correlation coefficient of light intensity If an energy coupling trend is found between adjacent intervals, S53 is executed again to generate a correction strategy. When the correlation coefficient of light intensity When the adjacent intervals are not considered to have an energy coupling trend, it is determined that there is no energy coupling trend.

[0014] S53: Based on S52, perform drift type identification and calibration strategy generation, including: when and At that time, the drift type was identified as single-zone energy attenuation type, and an incident angle adjustment strategy was generated simultaneously; when At that time, the drift type was identified as partitioned energy coupling type, and a refractive index adjustment strategy was generated simultaneously; Simultaneously, a complete adjustment matrix is ​​generated based on the calibration strategy; S54: Correct the complete adjustment matrix output in step S53 by using the current temperature control unit parameters below the waveguide to obtain the corrected optical field parameter matrix; S55: Repeat the test of the calibrated light intensity, and import the calibrated light intensity into the stability evaluation strategy to obtain the light intensity stability. If the light intensity stability is ≥95%, the energy drift calibration is considered to be effective; otherwise, repeat step S51. The maintenance records are updated synchronously at a fixed interval of 60 minutes.

[0015] Compared with the prior art, the technical effects of the present invention are as follows: 1. By introducing a transverse isolation zone and a refractive index gradient design, this invention completely blocks the optical field coupling path between adjacent partitions at the physical level, so that each partition unit forms a highly localized single energy peak. This successfully solves the problem of optical field competition and energy redistribution in the state of multi-molecule coexistence, ensuring that each single molecule can be independently coupled to its own enhanced optical field, thereby achieving the uniqueness and stability of the signal response and effectively eliminating the random signal fluctuation phenomenon commonly found in traditional methods. 2. This invention utilizes the synergistic effect of nano-confined holes and metal positioning islands to precisely anchor single molecules at the energy peak center under the dual mechanisms of mechanical constraint and electromagnetic enhancement, significantly improving the spatial accuracy of molecule fixation to the sub-ten nanometer level. Furthermore, through the coherent superposition effect of local surface plasmon resonance and waveguide mode, the light field energy is further focused to the location of the molecule, resulting in an order-of-magnitude increase in the excitation light intensity of single molecules, while reducing background noise interference and achieving a breakthrough improvement in signal-to-noise ratio. 3. Based on the real-time light intensity drift monitoring and dynamic feedback calibration system, it can intelligently identify drift types such as energy attenuation or partition coupling, and quickly restore the optimal working state through the coordinated control of incident angle fine adjustment and refractive index compensation. This allows the system to maintain light intensity stability of more than 95% during long-term operation, fundamentally solving the signal attenuation problem caused by environmental fluctuations or changes in material properties, and ensuring the long-term reliability and repeatability of single-molecule detection data. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic flowchart of the single-molecule optical signal enhancement method based on waveguide structure optimization of the present invention. Detailed Implementation

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0018] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0019] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0020] Example 1

[0021] like Figure 1 As shown in the figure, the single-molecule optical signal enhancement method based on waveguide structure optimization in this invention embodiment is as follows: Figure 1 As shown, the specific steps include the following: S1: A light guide layer is fabricated on a transparent substrate. Multi-zoned grooves are etched on the surface of the light guide layer to form multiple partition units. Lateral isolation strips are introduced between each partition to collect waveguide structure parameter sets. S1 includes: S11: Based on the refractive index of the transparent substrate material and target operating wavelength The light guide layer is prepared by chemical vapor deposition. It should be noted that, in this embodiment, the refractive index of the transparent substrate material is... The value range is 1.4~1.55; the target operating wavelength The value range is 500~700 nanometers; In this embodiment, the thickness of the light guide layer The following conditions must be met: ; in, The refractive index of the light guide layer is [value missing]. It should be noted that, in this embodiment, [value missing] The value range is 1.45 to 1.5; For the target operating wavelength; The thickness of the light guide layer; S12: A periodic groove array is formed on the surface of the light guide layer by electron beam exposure and dry etching to obtain a light guide layer structure with a periodic groove array. For example, in this embodiment, the effective propagation width of each partition in the periodic groove array ranges from 400 to 600 nanometers, and the depth of each groove unit is... The value ranges from 60 to 100 nanometers; The groove period of the light guide layer structure The following conditions must be met: ; in, Effective propagation width for each partition; This represents the gap width between adjacent partitions; S13: Isolation treatment is performed at the grooves in the periodic groove array to obtain a transverse isolation band. ; It should be noted that, in this embodiment, the width of each groove unit in the periodic groove array is used as the width of the transverse isolation strip; For example, in this embodiment, the isolation process can adopt two implementation strategies, specifically including: the first is to reduce the gap width One approach is to directly expose the air gap, creating the strongest refractive index difference; another approach is to fill a low-refractive-index oxide film using the sol-gel method, and then control the refractive index through annealing. It should be noted that, in this embodiment, the transverse isolation strip The refractive index difference needs to be greater than 0.3; transverse isolation band refractive index Controlled within the range of 1 to 1.20 for low-density oxides in air; transverse isolation zone The width needs to meet the following conditions, specifically: ; It should also be noted that, in this embodiment, this condition ensures that the lateral attenuation of the light field in adjacent partitions reaches more than 90% within the propagation distance, thereby achieving a physical mode barrier. S14: Based on the transverse isolation zone, the energy density ratio of the local light intensity distribution function is calculated. Simultaneously, single-mode propagation verification and coupling suppression verification are performed. If the verification is successful, the output is a set of waveguide structure parameters.

[0022] For example, in this embodiment, a strategy for calculating the energy density ratio is provided, specifically as follows: ; in, Energy density ratio; Light intensity at the center point of the partition; Light intensity at the boundary of the partition; It should be noted that, in this embodiment, When the peak intensity is 1 after normalization, it represents the light intensity at the center of the partition; The single-mode propagation verification process and coupling suppression verification process are specifically performed by near-field scanning microscopy or optical simulation. when If the mode energy is concentrated within the partition and lateral coupling is ignored, the output is a set of waveguide structure parameters. when If the condition is not met, the width or refractive index of the isolation zone needs to be adjusted, and step S13 needs to be repeated until the condition is met. ; It should be noted that, in this embodiment, step S1 aims to form a physical energy barrier to block the lateral coupling path of the light field at the structural level. S2: Based on the dynamic adjustment of the groove depth and the refractive index difference of the upper surface covering layer within the partition unit, the light field mode is induced to form a single energy peak at the center of the partition unit, and the energy concentration parameter is obtained. S2 includes: S21: Based on the waveguide structure parameter set, establish the longitudinal interference condition equation to obtain the depth ratio; For example, in this embodiment, the establishment of the longitudinal interference condition equation specifically involves: ;in, Indicates the depth ratio; The refractive index of the light guide layer; The refractive index of the transparent substrate material; A strategy for obtaining the depth ratio is provided, specifically: ;in, This represents the depth ratio that satisfies the local field concentration condition; The thickness of the light guide layer; The depth of each groove unit; S22: Based on the depth ratio and the refractive index of the light guide layer, the refractive index gradient distribution is designed by depositing a high refractive index film with a lateral gradient, and the refractive index distribution function of the upper surface cover layer is obtained.

[0023] For example, in this embodiment, the refractive index distribution function of the upper surface covering layer Specifically: ; in, The boundary refractive index of the upper surface coating layer is given. It should be noted that, in this embodiment, The value range is 1.45 to 1.50; The highest refractive index at the center of the upper surface coating layer. It should be noted that, in this embodiment, the highest refractive index at the center... The value range is 1.60 to 1.80; This is the refractive index gradient control factor, which aims to control the rate of refractive index decay. It should be noted that, in this embodiment, The value range is 0.0005 to 0.001; The horizontal position relative to the center of the partition; S23: Based on the refractive index distribution function and depth ratio, the energy attenuation coefficient is obtained. ; Calculate the energy density distribution curve based on the energy attenuation coefficient to determine the energy peak location; For example, in this embodiment, the strategy for obtaining the energy attenuation coefficient is as follows: ; in, This represents the energy attenuation coefficient. It should be noted that, in this embodiment, the energy attenuation coefficient... The value range is 0.5 to 0.15, which is intended to ensure that the light field forms a single enhancement peak at the center and that the intensity attenuation at the boundary exceeds 90%. The highest refractive index is at the center; The boundary refractive index; Indicates the depth ratio; The energy density distribution curve is specifically as follows: ; in, Horizontal position The light intensity at that location, The central peak light intensity is referred to as the central peak light intensity. It should be noted that, in this embodiment, the central peak light intensity is... Normalization to 1 represents the maximum energy, which is the peak value of the energy distribution curve; It should also be noted that, in this embodiment, the energy peak position is defined as the area within ±10 nanometers of the partition center. ; S24: Based on the energy peak position and energy decay coefficient The ratio of light intensity at the center of the partition to that at the partition boundary is calculated, the stability of the energy peak is verified, and the verification result is output as an energy concentration parameter. .

[0024] For example, in this embodiment, the strategy for obtaining the light intensity ratio is as follows: ;in, Indicates the ratio of light intensity; The light intensity at the center of the partition is referred to as the partition center light intensity. It should be noted that, in this embodiment, the light intensity at the center of the partition is... When defined as 1, it represents the maximum energy; Light intensity at the boundary of the partition; It should also be noted that, in this embodiment, the light intensity at the partition boundary is defined as half the width of the partition center. ; when When the difference in light intensity between the partition center and the partition boundary exceeds one order of magnitude, the light field concentration effect is in a stable state, satisfying the single-peak concentration condition, and the output is an energy concentration parameter. ; when When this happens, the refractive index gradient control factor is adjusted. Or readjust the depth ratio until the conditions are met. ; It should be noted that, in this embodiment, step S2 aims to ensure that each enhancement region contains only one energy center, providing a physical reference point for single-molecule localization and preventing energy from being evenly distributed among multiple molecules. S3: Based on the energy concentration parameter, single-molecule anchor points and nano-confined holes are constructed at the energy peak points of each partition unit. At the same time, the single molecules are matched one-to-one with the energy peak points to obtain a partitioned waveguide composite structure. S3 includes: S31: Based on the energy density distribution curve, the coordinates of the single-molecule anchor positioning points are determined by the nano-positioning system, and the coordinates of all partitions are integrated to obtain the set of single-molecule anchor positioning point coordinates. It should be noted that, in this embodiment, when the lateral position... Light intensity at the location Meet the conditions At that time, define the light intensity at the center of the partition. As the energy peak center; further, the coordinates of this coordinate system are determined as the coordinates of the single-molecule anchor point using a nano-positioning system. ,in, This indicates the location of the energy peak. The longitudinal reference plane of the waveguide surface; The set of coordinates of the single-molecule anchor points Specifically ; Where 1 and 2 are subscripts, representing the first partition and the second partition, respectively; S32: Based on the set of coordinates of single-molecule anchor points, chemical anchor points are constructed on the waveguide surface to obtain a chemical anchor positioning array.

[0025] For example, in this embodiment, the construction strategy of the chemical anchoring points is as follows: based on the set of single-molecule anchoring point coordinates, a circular opening is formed on the waveguide surface at the corresponding single-molecule anchoring point coordinate position by micro-contact printing or electron beam lithography; then, terminal functional groups are introduced into the opening region by silanization reaction; chemical anchoring points are formed, and at the same time, a chemical anchoring array with single-molecule recognition function is output. It should be noted that, in this embodiment, the thickness of the chemically modified layer... The value ranges from 1 to 3 nanometers; chemisorption density The following conditions must be met: ; in, Chemisorption density represents the number of functional groups per unit area; The diameter of the chemical anchor point; it should be noted that, in this embodiment, the diameter of the chemical anchor point... The value range is 5-10 nanometers; It should also be noted that, in this embodiment, when Controlled at 10 12 -10 13 When the number of molecules / cm² is in the range, it ensures that there is no overlapping adsorption effect after the adsorption of a single molecule; S33: Based on the chemical anchor positioning array and energy attenuation coefficient, a vertical nano-confined hole is formed on the waveguide surface to obtain a nano-confined hole array concentric with the chemical anchor positioning point. For example, in this embodiment, vertical nano-confined holes are formed on the waveguide surface by electron beam etching, with the diameter of each nano-confined hole ranging from 20 to 30 nanometers and the depth of each nano-confined hole ranging from 10 to 15 nanometers. The diameter of the nanoconfined pore Specifically: ; in, The diameter of the chemical anchor point; The depth of the nanoconfined pore Specifically: ; in, The energy decay coefficient; It should also be noted that, in this embodiment, the nano-confined pore structure forms mechanical constraints and local air gaps to prevent molecules from drifting laterally or being desorbed by solvent disturbance in the solution environment. S34: Based on a nano-confined hole array, a metal positioning island structure is formed at the bottom of the nano-confined holes; Hemispherical metal positioning islands are formed at the bottom of nano-confined pores using vacuum evaporation or atomic layer deposition techniques; For example, in this embodiment, the material of the metal positioning island structure is gold or silver; the radius of the metal positioning island... The value ranges from 8 to 12 nanometers; surface charge density The range of values ​​is Thickness distribution The specific definition is as follows: ;in, The vertical distance from the bottom of the hole; It should be noted that the surface charge density of the metal island A localized surface plasmon resonance field is generated, which coherently superimposes with the waveguide master mode, enhancing the energy localization effect; S35: Verification of single-molecule-optical field coupling through metal positioning island structure and chemical anchor positioning array; When the verification is successful, a single-molecule-optical-field composite unit is formed, resulting in the verified partitioned waveguide composite structure. If the verification fails, repeat this step.

[0026] It should be noted that in this embodiment, the surface-activated waveguide structure is immersed in a monomolecular solution, and the molecular concentration of the monomolecular solution is... Controlled The probability of successful single-molecule binding is determined by the adsorption probability function to ensure that only one molecule is bound per confined pore on average. After a single molecule is successfully bound, fluorescence confocal detection or AFM scanning is used to verify that the molecule exists only in the center of the metal island. For example, in this embodiment, the adsorption probability function is specifically: ; in, This represents the probability of successful binding of a single molecule. The surface adsorption rate constant; The soaking time is [not specified in the provided text]. It should be noted that, in this embodiment, [the soaking time is specified in the provided text]. The value range is 100~300 seconds; When a single light spot is detected in each partition, it indicates that the verification is successful, and a single molecule-light field composite unit is formed, resulting in the verified partitioned waveguide composite structure. If multiple light spots are detected in each partition or no light spots are detected, the molecular concentration and soaking time in this step need to be adjusted, and the process should be repeated. It should also be noted that, in this embodiment, step S3 aims to precisely couple each single molecule with an independent energy enhancement center, thereby forming a single molecule-light field composite unit that does not interfere with each other in space. S4: Place the partitioned waveguide composite structure under excitation light, and use incident angle control and mode coupling to excite the single-mode region of the corresponding partition. The spectral intensity of each partition unit is collected synchronously to obtain enhanced optical signal data; S4 includes: S41: Based on the partitioned waveguide composite structure, calculate the initial incident angle and set the polarization direction; Extracting the waveguide structure parameter set and the highest refractive index at the center of the partitioned waveguide composite structure. ; The waveguide structure parameter set includes: target operating wavelength. , thickness of light guide layer The highest refractive index at the center Refractive index of light guide layer ; For example, in this embodiment, a calculation strategy for the incident angle is provided, specifically as follows: ; in, The refractive index is the incident medium. It should be noted that, in this embodiment, This represents air, and its value ranges from 1. Let be the angle of incidence of light. It should be noted that, in this embodiment, The value range is 45 degrees to 65 degrees; The refractive index of the light guide layer; The thickness of the light guide layer; For the target operating wavelength; This refers to the coupling mode order. It should be noted that, in this embodiment, The value is 1; It should be noted that, in this embodiment, the waveguide structure parameter set and the highest refractive index at the center are used in the partitioned waveguide composite structure. Adjust the incident angle so that the light excites only the fundamental mode; The polarization direction It is controlled by the linear polarization of the light source, selecting either 90 degrees parallel or 0 degrees perpendicular to match the electric field direction of the waveguide master mode; S42: Calculate the effective mode propagation constant and energy coupling efficiency of each partition based on the incident angle, polarization direction and waveguide structure parameter set.

[0027] For example, in this embodiment, the effective mode propagation constant is specifically: ;in, is the effective mode propagation constant, which describes the phase progression rate of light in a partition; The refractive index of the light guide layer; For the target operating wavelength; For example, in this embodiment, the energy coupling efficiency is specifically: ; in, Energy coupling efficiency reflects the proportion of incident light energy entering the single-mode channel; The refractive index of the transverse isolation zone; Effective propagation width for each partition; For the target operating wavelength; It should be noted that, in this embodiment, the incident angle is adjusted. Improve energy coupling efficiency Maximizing this ensures that light energy is concentrated and propagates independently within each zone; S43: Based on the effective mode propagation constant, energy coupling efficiency and partitioned waveguide composite structure, calculate the total optical field intensity distribution within the partition, and determine the single-molecule excitation intensity according to the total optical field intensity distribution within the partition. For example, in this embodiment, the total light field intensity distribution within the partition is specifically as follows: ; in, The total light field intensity distribution within the partition; The intensity distribution of the waveguide dominant mode along the longitudinal direction; The local field enhancement coefficient is used. It should be noted that, in this embodiment, The value range is 1.2-1.8; To attenuate the plasma field on the surface of the metal positioning island; The waveguide dominant mode propagation intensity distribution along the longitudinal direction Specifically: ;in, The central peak light intensity; The effective mode propagation constant; Plasma field attenuation on the surface of the metal positioning island Specifically: ;in, The radius of the metal positioning island; The single-molecule excitation light intensity Specifically: ; It should also be noted that, in this embodiment, when the single-molecule excitation light intensity... When this occurs, it indicates that the single molecule is in the optimal excitation region; S44: Based on the single-molecule excitation intensity and the set of coordinates of the single-molecule anchor points in S3. Calculate the single-molecule emission spectral intensity of each partition to form a partition spectral matrix; For example, in this embodiment, a single-molecule emission spectral intensity is provided. Specifically: ; in, Regarding molecular quantum efficiency, it should be noted that in this embodiment, The value range is 0.4-0.9; The intensity of light excitation for a single molecule; As for the absorption cross section, it should be noted that in this embodiment, The range of values ​​is approximately ; This represents the shape function of the molecular emission spectrum; it should be noted that in this embodiment, It is a normal distribution; The partitioned spectral matrix is ​​specifically as follows: ; Where 1 and 2 are subscripts, representing the first partition and the second partition, respectively; S45: Obtain the reference spectrum in the unenhanced state. , partition spectral matrix Compared with reference spectrum The comparison yielded the enhancement ratio for each partition. Synchronous output of average enhancement factor And make a judgment; when If a significant enhancement change is detected in the waveguide structure, step S5 is executed, and the enhanced optical signal data is output simultaneously. when If the waveguide structure does not show any enhancement change, repeat step S4.

[0028] The reference spectrum of the unenhanced state was measured using a waveguide-free sample. For example, in this embodiment, the enhancement ratio of each partition is... Specifically: ; in, This represents the emission spectral intensity of the i-th partition; The reference spectrum representing the unenhanced state; The average enhancement factor Specifically: Where n represents the number of partitions; It should be noted that, in this embodiment, step S4 aims to completely suppress the competition of the light field through independent partitioning excitation and local energy allocation, thereby solving the signal interference problem when multiple molecules coexist. S5: Perform periodic detection on the partitioned waveguide composite structure, calculate the drift coefficient of the light intensity of each partition, and perform correction processing based on the drift coefficient.

[0029] S5 includes: S51: Based on partitioned spectral matrix Record the initial light intensity of each partition and generate a light intensity reference matrix. ; For example, in this embodiment, an initial light intensity of the i-th partition is provided. The acquisition strategy is as follows: ; in, Indicates the partition number, and ; This is the initial detection time; For the i-th partition in time spectral distribution; S52: Obtain real-time detected light intensity Based on real-time detection of light intensity and light intensity reference matrix Calculate the light intensity drift coefficient And make a judgment; when When, it indicates enhancement; when When, it indicates decay; when If the value is ≥0.05, it is determined that energy drift has occurred; Simultaneously based on the partitioned spectral matrix Light intensity reference matrix Calculate the correlation coefficient of light intensity between adjacent partitions And based on the light intensity drift coefficient Make a judgment; When the correlation coefficient of light intensity If an energy coupling trend is found between adjacent intervals, S53 is executed again to generate a correction strategy. When the correlation coefficient of light intensity When the adjacent intervals are not considered to have an energy coupling trend, it is determined that there is no energy coupling trend.

[0030] Among them, the real-time light intensity is obtained through a photoelectric detection array; For example, in this embodiment, the light intensity drift coefficient Specifically: ; For example, in this embodiment, the light intensity correlation coefficient Specifically: ; S53: Based on S52, perform drift type identification and calibration strategy generation, including: when and At that time, the drift type was identified as single-zone energy attenuation type, and an incident angle adjustment strategy was generated simultaneously; when At that time, the drift type was identified as partitioned energy coupling type, and a refractive index adjustment strategy was generated simultaneously; Simultaneously, a complete adjustment matrix is ​​generated based on the calibration strategy; For example, in this embodiment, the incident angle adjustment strategy Specifically: ;in, The angle sensitivity coefficient is used. It should be noted that, in this embodiment, The value range is 0.2 to 0.5; The refractive index adjustment strategy Specifically: ;in, This is the refractive index compensation coefficient. It should be noted that, in this embodiment, The value range is 0.01 to 0.05; The complete adjustment matrix is ​​specifically as follows: ; S54: Correct the complete adjustment matrix output in step S53 by using the current temperature control unit parameters below the waveguide to obtain the corrected optical field parameter matrix; For example, in this embodiment, the modified light field parameter matrix is ​​specifically: ;in, This is the corrected angle of incidence; The corrected refractive index; It should be noted that in this embodiment, angle correction is achieved through an electrically controlled rotating platform with a resolution better than 0.01 degrees; refractive index correction is performed using a Peltier micromodule. The corrected angle of incidence is specifically: ;in, Angle of incidence; This is the adjustment amount for the angle of incidence; The corrected refractive index is specifically: ;in, The refractive index; This is the refractive index adjustment amount; This is the coefficient of refractive index in response to temperature; The temperature rise of the local temperature control unit should be noted, in this embodiment, The value range is 1-5k; S55: Repeat the test of the calibrated light intensity, and import the calibrated light intensity into the stability evaluation strategy to obtain the light intensity stability. If the light intensity stability is ≥95%, the energy drift calibration is considered to be effective; otherwise, repeat step S51. The maintenance records are updated synchronously at a fixed interval of 60 minutes.

[0031] For example, in this embodiment, the calibrated light intensity is specifically: ;in, The calibrated light intensity; The i-th partition in time spectral distribution function; The light intensity stability is specifically as follows: ;in, The initial light intensity; It should be noted that, in this embodiment, step S5 aims to ensure that the partitioned light field structure remains independent in the long term, and to ensure that energy is no longer redistributed from the operational perspective, thereby achieving the stability and uniqueness of single-molecule signal enhancement.

[0032] Example 2

[0033] This embodiment provides an electronic device, including: a processor and a memory, wherein the memory stores a computer program that can be called by the processor; The processor executes the aforementioned single-molecule optical signal enhancement method based on waveguide structure optimization by calling the computer program stored in memory.

[0034] This electronic device can vary considerably depending on its configuration or performance. It may include one or more Central Processing Units (CPUs) and one or more memories, wherein the memory stores at least one computer program, which is loaded and executed by the processor to implement the waveguide structure optimization-based single-molecule optical signal enhancement method provided in the above-described embodiment. The electronic device may also include other components for implementing its functions; for example, it may have wired or wireless network interfaces and input / output interfaces for data input and output. Details will not be elaborated upon in this embodiment.

[0035] Example 3

[0036] This embodiment proposes a computer-readable storage medium on which an erasable and rewritable computer program is stored. When the computer program runs on the computer device, it causes the computer device to execute the above-described single-molecule optical signal enhancement method based on waveguide structure optimization.

[0037] For example, computer-readable storage media can be read-only memory (ROM), random access memory (RAM), compact disc read-only memory (CD-ROM), magnetic tape, floppy disk, and optical data storage devices.

[0038] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0039] It should be understood that determining B based on A does not mean determining B solely based on A; it also means determining B based on A and / or other information.

[0040] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the flow or function according to the embodiments of the present invention is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. Computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired network and / or wireless network. A computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. Available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media. Semiconductor media can be solid-state drives (SSDs).

[0041] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0042] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0043] In the several embodiments provided by this invention, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only one method, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0044] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0045] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0046] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A single-molecule optical signal enhancement method based on waveguide structure optimization, characterized in that, The method includes: S1: A light guide layer is fabricated on a transparent substrate. Multi-zoned grooves are etched on the surface of the light guide layer to form multiple partition units. Lateral isolation strips are introduced between each partition to collect waveguide structure parameter sets. S2: Based on the dynamic adjustment of the groove depth and the refractive index difference of the upper surface covering layer within the partition unit, the light field mode is induced to form a single energy peak at the center of the partition unit, and the energy concentration parameter is obtained. S3: Based on the energy concentration parameter, single-molecule anchor points and nano-confined holes are constructed at the energy peak points of each partition unit. At the same time, the single molecules are matched one-to-one with the energy peak points to obtain a partitioned waveguide composite structure. S4: Place the partitioned waveguide composite structure under excitation light, and use incident angle control and mode coupling to excite the single-mode region of the corresponding partition. The spectral intensity of each partition unit is collected synchronously to obtain enhanced optical signal data; S5: Perform periodic detection on the partitioned waveguide composite structure, calculate the drift coefficient of the light intensity of each partition, and perform correction processing based on the drift coefficient; S1 includes: S11: Based on the refractive index of the transparent substrate material and target operating wavelength The light guide layer is prepared by chemical vapor deposition. S12: A periodic groove array is formed on the surface of the light guide layer by electron beam exposure and dry etching to obtain a light guide layer structure with a periodic groove array. S13: Isolation treatment is performed at the grooves in the periodic groove array to obtain a transverse isolation band. ; S14: Based on the transverse isolation zone, the energy density ratio of the local light intensity distribution function is calculated. Simultaneously, single-mode propagation verification and coupling suppression verification are performed. If the verification is successful, the output is a set of waveguide structure parameters.

2. The single-molecule optical signal enhancement method based on waveguide structure optimization according to claim 1, characterized in that, S2 include: S21: Based on the waveguide structure parameter set, establish the longitudinal interference condition equation to obtain the depth ratio; S22: Based on the depth ratio and the refractive index of the light guide layer, the refractive index gradient distribution is designed by depositing a high refractive index film with a lateral gradient, and the refractive index distribution function of the upper surface cover layer is obtained.

3. The single-molecule optical signal enhancement method based on waveguide structure optimization according to claim 2, characterized in that, S2 also includes: S23: Based on the refractive index distribution function and depth ratio, the energy attenuation coefficient is obtained. ; Calculate the energy density distribution curve based on the energy attenuation coefficient to determine the energy peak location; S24: Based on the energy peak position and energy decay coefficient The ratio of light intensity at the center of the partition to that at the partition boundary is calculated, the stability of the energy peak is verified, and the verification result is output as an energy concentration parameter. .

4. The single-molecule optical signal enhancement method based on waveguide structure optimization according to claim 3, characterized in that, S3 include: S31: Based on the energy density distribution curve, the coordinates of the single-molecule anchor positioning points are determined by the nano-positioning system, and the coordinates of all partitions are integrated to obtain the set of single-molecule anchor positioning point coordinates. S32: Based on the set of coordinates of single-molecule anchor points, chemical anchor points are constructed on the waveguide surface to obtain a chemical anchor positioning array.

5. The single-molecule optical signal enhancement method based on waveguide structure optimization according to claim 4, characterized in that, S3 also includes: S33: Based on the chemical anchor positioning array and energy attenuation coefficient, a vertical nano-confined hole is formed on the waveguide surface to obtain a nano-confined hole array concentric with the chemical anchor positioning point. S34: Based on a nano-confined hole array, a metal positioning island structure is formed at the bottom of the nano-confined holes; S35: Verification of single-molecule-optical field coupling through metal positioning island structure and chemical anchor positioning array; When the verification is successful, a single-molecule-optical-field composite unit is formed, resulting in the verified partitioned waveguide composite structure. If the verification fails, repeat this step.

6. The single-molecule optical signal enhancement method based on waveguide structure optimization according to claim 5, characterized in that, S4 include: S41: Based on the partitioned waveguide composite structure, calculate the initial incident angle and set the polarization direction; S42: Calculate the effective mode propagation constant and energy coupling efficiency of each partition based on the incident angle, polarization direction and waveguide structure parameter set.

7. The single-molecule optical signal enhancement method based on waveguide structure optimization according to claim 6, characterized in that, S4 also includes: S43: Based on the effective mode propagation constant, energy coupling efficiency and partitioned waveguide composite structure, calculate the total optical field intensity distribution within the partition, and determine the single-molecule excitation intensity according to the total optical field intensity distribution within the partition. S44: Based on the single-molecule excitation intensity and the set of coordinates of the single-molecule anchor points in S3. Calculate the single-molecule emission spectral intensity of each partition to form a partition spectral matrix; S45: Obtain the reference spectrum in the unenhanced state. , partition spectral matrix Compared with reference spectrum The comparison yielded the enhancement ratio for each partition. Synchronous output of average enhancement factor And make a judgment; when If a significant enhancement change is detected in the waveguide structure, step S5 is executed, and the enhanced optical signal data is output simultaneously. when If the waveguide structure does not show any enhancement change, repeat step S4.

8. The single-molecule optical signal enhancement method based on waveguide structure optimization according to claim 7, characterized in that, S5 include: S51: Based on partitioned spectral matrix Record the initial light intensity of each partition and generate a light intensity reference matrix. ; S52: Obtain real-time detected light intensity Based on real-time detection of light intensity and light intensity reference matrix Calculate the light intensity drift coefficient And make a judgment; when When, it indicates enhancement; when When, it indicates decay; when If the value is ≥0.05, it is determined that energy drift has occurred; Simultaneously based on the partitioned spectral matrix Light intensity reference matrix Calculate the correlation coefficient of light intensity between adjacent partitions And based on the light intensity drift coefficient Make a judgment; When the correlation coefficient of light intensity If an energy coupling trend is found between adjacent intervals, S53 is executed again to generate a correction strategy. When the correlation coefficient of light intensity When the adjacent intervals are not considered to have an energy coupling trend, it is determined that there is no energy coupling trend.

9. The single-molecule optical signal enhancement method based on waveguide structure optimization according to claim 8, characterized in that, S5 also includes: S53: Based on S52, perform drift type identification and calibration strategy generation, including: when and At that time, the drift type was identified as single-zone energy attenuation type, and an incident angle adjustment strategy was generated simultaneously; when At that time, the drift type was identified as partitioned energy coupling type, and a refractive index adjustment strategy was generated simultaneously; Simultaneously, a complete adjustment matrix is ​​generated based on the calibration strategy; S54: Correct the complete adjustment matrix output in step S53 by using the current temperature control unit parameters below the waveguide to obtain the corrected optical field parameter matrix; S55: Repeat the test of the calibrated light intensity, and import the calibrated light intensity into the stability evaluation strategy to obtain the light intensity stability. If the light intensity stability is ≥95%, the energy drift calibration is considered to be effective; otherwise, repeat step S51. The maintenance records are updated synchronously at a fixed interval of 60 minutes.

Images