A thermal detection system and chiral substance identification method

Abstract

This application discloses a thermal detection system and a method for identifying chiral substances, relating to the field of micro-nano optical technology. The thermal detection system and the method for identifying chiral substances are based on the structure of the thermal detection system and the steps of the method. The chiral substance to be detected is configured into a corresponding test solution, and then a sample of the test solution is taken and placed in an absorber. The surface plasmon effect generated when the metal resonant layer receives chiral light irradiation is used to output a corresponding thermal signal. The thermal signal is then captured and analyzed by the thermal detection system, achieving high-precision identification of the chiral substance. Compared to traditional circular dichroism and circularly polarized fluorescence spectrometers, the technical solution of this application has a simple structure, is easy to operate, and has lower requirements for the concentration and volume of the test sample.

Description

Technical Field

[0001] The present application relates to the field of micro-nano optical technology, and in particular to a thermal detection system and a method for identifying chiral substances. Background Art

[0002] Chirality is a fundamental property of nature, playing a vital role in chemistry, biology, medicine, and materials science. Due to the non-centrosymmetry of molecular structures, chiral structures possess unique physical properties, such as excellent nonlinear optical activity, the ability to generate second and third harmonics, circularly polarized luminescence, and properties useful for optical sensing and detection.

[0003] Existing methods for detecting chiral substances generally use circular dichroism and circularly polarized fluorescence spectrometers for detection. However, these detection devices have complex structures and have high requirements for the concentration and volume of the detection samples, making them difficult to apply to the field of integrated micro-nano optoelectronic devices.

[0004] The above content is only used to assist in understanding the technical solution of this application and does not constitute an admission that the above content is prior art. Summary of the Invention

[0005] The main purpose of this application is to provide a thermal detection system and a chiral substance identification method, aiming to achieve convenient and accurate chiral substance identification.

[0006] To achieve the above objectives, the present application proposes a thermal detection system for identifying chiral substances, the thermal detection system comprising:

[0007] A laser light source, used for emitting laser light;

[0008] a stage for carrying the absorber;

[0009] an optical-mechanical module, disposed correspondingly to the laser light source and the stage, respectively; the optical-mechanical module is configured to convert the laser light emitted by the laser light source into chiral light and output the chiral light to the stage, so that the absorber carried by the stage outputs a corresponding heat signal when receiving the chiral light;

[0010] a temperature measuring component, disposed corresponding to the stage, and configured to receive the thermal signal to obtain a corresponding temperature;

[0011] The absorber comprises:

[0012] substrate layer;

[0013] a bottom metal layer, the bottom metal layer being disposed on one side of the substrate layer;

[0014] a dielectric layer, the dielectric layer being disposed on a side of the bottom metal layer away from the substrate layer;

[0015] A metal resonance layer is provided on a side of the dielectric layer away from the bottom metal layer. The metal resonance layer is used to generate a surface plasmon effect and output a corresponding thermal signal when receiving chiral light.

[0016] In one embodiment, the thermal detection system further includes a camera module, which is arranged corresponding to the optomechanical module; the camera module is used to obtain image information of the absorber through the optomechanical module to adjust the position of the absorber based on the image information.

[0017] In one embodiment, the optical-mechanical module includes:

[0018] a half-reflecting half-mirror lens, disposed corresponding to the laser light source, configured to reflect a portion of the laser light emitted by the laser light source to enter the camera module, and transmit another portion of the laser light emitted by the laser light source to illuminate the absorber;

[0019] a polarizer, arranged corresponding to the half-reflecting half-mirror lens, for converting the laser light transmitted by the half-reflecting half-mirror lens into linearly polarized light;

[0020] a quarter glass plate, arranged corresponding to the polarizer, for converting the linearly polarized light into circularly polarized light;

[0021] A microscope objective lens is respectively arranged corresponding to the quarter glass slide and the stage, and is used to focus the circularly polarized light on the absorber surface of the stage.

[0022] In one embodiment, the thermal detection system further comprises:

[0023] A rotating platform is provided on which the polarizer and / or the quarter glass are arranged so as to control the direction of the circularly polarized light by driving the polarizer and / or the quarter glass to rotate.

[0024] In addition, to achieve the above-mentioned purpose, the present application also proposes a method for identifying chiral substances, which is based on the above-mentioned thermal detection system and includes:

[0025] Step S100, preparing the chiral substance to be tested into a corresponding test solution;

[0026] Step S200, taking a sample from the solution to be tested and placing it in the absorber, and placing the absorber in the thermal detection system;

[0027] Step S300: Turning on the laser light source to emit laser light, controlling the optical-mechanical module to convert the laser light into chiral light having circular polarization in a first direction, adjusting the position of the absorber so that the chiral light spot is located in the metal resonant layer, and continuously acquiring first temperature change data of the absorber for a first preset time period based on the temperature measurement component, and then turning off the laser light source;

[0028] Step S400: Turning on the laser light source to emit laser light, controlling the optical-mechanical module to convert the laser light into chiral light having a second circularly polarized direction, adjusting the position of the absorber so that the chiral light spot is located in the metal resonant layer, and continuously acquiring second temperature change data of the absorber for a first preset time period based on the temperature measurement component, and then turning off the laser light source;

[0029] Step S500, calculating a photothermal CD value based on the first temperature change data and the second temperature change data;

[0030] Step S600 : comparing the photothermal CD value with preset reference data to obtain an identification result of the chiral substance.

[0031] In one embodiment, before step S500, the method further includes:

[0032] Step S700: Turning on the laser light source to emit laser light, controlling the optical-mechanical module to convert the laser light into chiral light having circular polarization in a first direction, adjusting the position of the absorber so that the chiral light spot is not located in the metal resonant layer, obtaining third temperature change data of the absorber within a first preset time period based on the temperature measurement component, and then turning off the laser light source;

[0033] Step S800, turn on the laser light source to emit laser, and control the optical machine module to convert the laser into chiral light with circular polarization in the second direction, adjust the position of the absorber so that the light spot of the chiral light is not in the metal resonance layer, and obtain the fourth temperature change data of the absorber within the first preset time period based on the temperature measurement component, and then turn off the laser light source.

[0034] In one embodiment, before step S500, the method further includes:

[0035] The steps S300 , S400 , S700 and S800 are respectively performed multiple times to reduce errors in the acquired first temperature change data, second temperature change data, third temperature change data and fourth temperature change data.

[0036] In one embodiment, before the laser light source is turned on each time, the absorber is kept at an initial temperature at which no surface plasmon effect is generated.

[0037] The technical solution proposed in this application, based on the structure of a thermal detection system and the steps of a chiral substance identification method, achieves high-precision identification of chiral substances by configuring the chiral substance to be tested into a corresponding test solution, sampling the test solution and placing it in an absorber. The surface plasmon effect generated by the metal resonant layer receiving chiral light irradiation outputs a corresponding thermal signal, which is then captured and analyzed by the thermal detection system. Compared to traditional circular dichroism and circularly polarized fluorescence spectrometers, the technical solution proposed in this application has a simple structure, is easy to operate, and has lower requirements for sample concentration and volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0040] Figure 1 A schematic diagram of the structure of an embodiment of the thermal detection system of the present application is provided;

[0041] Figure 2 A schematic structural diagram of an absorber according to an embodiment of the present application;

[0042] Figure 3 A schematic structural diagram of another embodiment of the absorber of the present application;

[0043] Figure 4 A schematic structural diagram of another embodiment of the thermal detection system of the present application;

[0044] Figure 5 A schematic diagram of a process for identifying a chiral substance according to an embodiment of the present invention;

[0045] Figure 6 An operational diagram of an embodiment of the method for identifying a chiral substance of the present application;

[0046] Figure 7 A schematic diagram of a process flow diagram of another embodiment of the method for identifying chiral substances of the present application;

[0047] Figure 8 An operation diagram of another embodiment of the chiral substance identification method of the present application;

[0048] Figure 9 Schematic diagram of circular dichroism spectra of the absorber with different arm lengths in the chiral structure of this application;

[0049] Figure 10 A schematic diagram of the surface plasmon effect generated by the metal resonance layer in the time domain A to D according to an embodiment of the chiral substance identification method of the present application;

[0050] Figure 11 Photothermal CD and its comparison diagram when adding different concentrations of L-lactic acid provided in an embodiment of the chiral substance identification method of the present application;

[0051] Figure 12 This is the photothermal CD and its comparison diagram when adding different chiral substances to be tested, provided in one embodiment of the chiral substance identification method of the present application.

[0052] Description of Figure Numbers:

[0053] 11. Substrate layer; 12. Bottom metal layer; 13. Dielectric layer; 14. Metal resonance layer; 20. Laser light source; 30. Stage; 40. Opto-mechanical module; 41. Half-reflective half-mirror lens; 42. Polarizer; 43. Quarter-glass slide; 44. Microscope objective; 45. Laser incident port; 51. Thermocouple; 52. Thermocouple temperature measurement platform; 61. Camera; 62. Terminal device; 71. Rotating platform body; 72. Clamp; 73. Turntable.

[0054] The purpose, features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0055] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0056] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0057] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0058] Chirality is a fundamental property of nature, playing a vital role in chemistry, biology, medicine, and materials science. Due to the non-centrosymmetry of molecular structures, chiral structures possess unique physical properties, such as excellent nonlinear optical activity, the generation of second and third harmonics, circularly polarized luminescence, and applications in optical sensing and detection.

[0059] Existing methods for detecting chiral substances generally use circular dichroism and circularly polarized fluorescence spectrometers for detection. However, these detection devices have complex structures and have high requirements for the concentration and volume of the detection samples, making them difficult to apply to the field of integrated micro-nano optoelectronic devices.

[0060] This application proposes a thermal detection system for identifying chiral substances, referring to Figure 1 The thermal detection system includes a laser light source 20, a stage 30, an optical-mechanical module 40 and a temperature measurement component. The optical-mechanical module 40 is respectively arranged corresponding to the laser light source 20 and the stage 30, and the temperature measurement component is arranged corresponding to the stage 30; the laser light source 20 is used to emit laser light, and the stage 30 is used to carry an absorber. The optical-mechanical module 40 is used to convert the laser light emitted by the laser light source 20 into chiral light and output it to the stage 30, so that the absorber carried by the stage 30 outputs a corresponding thermal signal when receiving chiral light irradiation, and the temperature measurement component is used to receive the thermal signal to obtain the corresponding temperature.

[0061] In this embodiment, the laser light source 20 serves as a light source system, providing stable laser output. Because the absorber is fabricated through simulation based on this laser light source 20, it matches the laser wavelength of the laser light source 20, thereby generating a significant difference in thermal signal when receiving chiral light. The laser light source 20 can select a wavelength within the visible or near-infrared range to better excite the surface plasmon effect of the metal resonant layer 14.

[0062] In this embodiment, stage 30 is used to stably support the absorber. In one feasible embodiment, stage 30 can be designed with a fine-tuning mechanism to precisely adjust the position of the absorber, ensuring that the chiral light spot accurately illuminates the intended area of ​​the absorber. Stage 30 can also be integrated with a cooling device to control the absorber temperature, thereby reducing the impact of temperature fluctuations on measurement results.

[0063] In this embodiment, the structure of the absorber is as follows: Figure 2 The absorber includes a substrate layer 11, a bottom metal layer 12, a dielectric layer 13 and a metal resonance layer 14. The bottom metal layer 12 is arranged on one side of the substrate layer 11, the dielectric layer 13 is arranged on the side of the bottom metal layer 12 away from the substrate layer 11, and the metal resonance layer 14 is arranged on the side of the dielectric layer 13 away from the bottom metal layer 12. The metal resonance layer 14 is used to generate a surface plasmon effect when receiving chiral light irradiation and output a corresponding thermal signal.

[0064] In this embodiment, the substrate layer 11 can be made of a silicon wafer or a glass wafer to support the structure of the entire absorber. The bottom metal layer 12 can be made of metal materials such as gold, silver or copper. In this embodiment, gold is used as the material of the bottom metal layer 12 to improve the stability and thermal conductivity of the absorber. The dielectric layer 13 can be made of dielectric materials such as silicon dioxide, silicon nitride or aluminum oxide to isolate the bottom metal layer 12 and the metal resonant layer 14, while improving the absorption efficiency of the metal resonant layer 14 for chiral light. In this embodiment, the metal resonant layer 14 is made of gold and includes at least one chiral structure to generate a surface plasmon effect and output a thermal signal when receiving chiral light. The design of the chiral structure enables the metal resonant layer 14 to have a higher absorption efficiency for chiral light in a specific direction, thereby generating a more obvious thermal signal, which facilitates the identification of chiral substances.

[0065] In this embodiment, the chiral structure can be a spiral, arc, or other non-centrosymmetric shape, so that when irradiated by chiral light, it generates a surface plasmon effect and outputs a corresponding thermal signal. In one feasible embodiment, the chiral structure is a "Z"-shaped structure composed of two gold quadrangular prisms, with one end of one quadrangular prism connected to the middle of the other quadrangular prism, forming a non-centrosymmetric structure.

[0066] In a feasible embodiment, the metal resonance layer 14 can be configured as a plurality of independent units to form a plurality of metal resonance regions. Figure 3 The metal resonance regions are deposited in groups of three on the same dielectric layer 13 to form nine independent metal resonance regions, so as to realize the separate detection of different regions of the chiral substance to be detected and improve the detection efficiency.

[0067] Understandably, the reference Figure 9 , the circular dichroism spectra of the absorber will vary depending on the arm length of the chiral structure. Furthermore, the shape and arrangement of the chiral structure will also affect the characteristics of its circular dichroism spectrum. Therefore, in this embodiment, the shape, size, and arrangement of the chiral structure can be designed and adjusted according to actual needs to achieve better chiral substance identification. For example, COMSOL finite element simulation software can be used to simulate the absorber based on the laser wavelength of the laser light source 20, a preset absorptivity, and a preset photothermal CD (Circular Dichroism) value to adjust parameters such as the arm length and arm width of the chiral structure, as well as the arrangement density and arrangement of the chiral structure on the metal resonant layer 14, to achieve optimal chiral substance identification.

[0068] In this embodiment, the laser wavelength of the laser light source 20 can be determined by the model of the laser light source 20, and a wavelength that can excite the surface plasmon effect of the metal resonance layer 14 is generally selected. The preset absorptivity can be estimated based on the characteristics of the metal resonance layer 14 material and the design of the chiral structure. The preset photothermal CD value is set according to the possible photothermal CD value range of the chiral substance to be measured, so as to optimize the design of the chiral structure in the simulation, so that when the absorber receives chiral light irradiation from a specific direction, it can produce a significant difference in thermal signal, thereby improving the accuracy and reliability of chiral substance identification. The chiral structure optimized by simulation can further guide the parameter setting and process flow in the actual preparation process, ensuring that the prepared absorber has excellent chiral substance identification performance.

[0069] In one feasible embodiment, the absorber utilizes a metamaterial absorber. Metamaterials refer to materials that exhibit properties that are rare or difficult to observe in nature, and are typically composed of multiple components made of composite materials such as metals. The unique properties of metamaterials do not derive from the characteristics of the material itself, but rather from their innovative structural design, such as metamaterial absorbers that can achieve near-100% absorption. Among these, chiral metamaterial absorbers (CMMAs) are a type of metamaterial that can block the continued transmission of incident electromagnetic waves and exhibit different optical responses when interacting with left and right circularly polarized light. In this embodiment, the use of metamaterial absorbers can further improve the accuracy and sensitivity of chiral substance identification.

[0070] In one feasible embodiment, after the absorber is prepared, an absorption spectrum test can be performed to determine the absorber's absorption characteristics (e.g., absorption peak wavelength, photothermal CD value, etc.). Specifically, the absorber can be tested using a spectrometer. Light of different wavelengths is irradiated onto the absorber, and the absorbance of the absorber at different wavelengths is measured to obtain the absorber's absorption spectrum. By comparing the simulated absorption characteristics with the absorption characteristics obtained from actual testing, it can be determined whether the absorber meets the design requirements. If the absorber's absorption characteristics deviate from the design requirements, the parameters of the chiral structure can be further adjusted, and the fabrication and testing can be repeated until the design requirements are met.

[0071] In this embodiment, the optical-mechanical module 40 is capable of converting the linearly polarized light emitted by the laser light source 20 into chiral light. In a feasible embodiment, the optical-mechanical module 40 includes a half-reflecting half-mirror 41, a polarizer 42, a quarter-glass 43, and a microscope objective 44. In this embodiment, the optical-mechanical module also includes a laser incident port 45, which is respectively arranged corresponding to the half-reflecting half-mirror 41 and the laser light source 20, so that the laser emitted by the laser light source 20 can be injected through the laser incident port 45 to reach the half-reflecting half-mirror 41, and the half-reflecting half-mirror 41 reflects a part of the incident laser light to enter the camera 61 module, and transmits another part of the laser light emitted by the laser light source 20 to illuminate the absorber. The polarizer 42 is arranged corresponding to the half-reflecting half-mirror 41, and is used to convert the laser light transmitted by the half-reflecting half-mirror 41 into linearly polarized light. The quarter-glass 43 is arranged corresponding to the polarizer 42, and is used to convert the linearly polarized light into circularly polarized light.

[0072] In this embodiment, a microscope objective lens 44 is positioned corresponding to the quarter-slide 43 and the stage 30, respectively, to focus the circularly polarized light onto the absorber surface of the stage 30. The focusing action of the microscope objective lens 44 ensures that the circularly polarized light accurately impinges upon the metal resonant layer 14 of the absorber, thereby stimulating the surface plasmon effect and generating a thermal signal. Parameters such as the magnification and numerical aperture of the microscope objective lens 44 can be selected based on actual needs to achieve optimal focusing.

[0073] In this embodiment, the temperature measuring component is used to receive the thermal signal output by the absorber and convert it into a measurable temperature value. In a feasible embodiment, the temperature measuring component includes a thermocouple 51 and a thermocouple temperature measuring platform 52, and the thermocouple 51 and the thermocouple temperature measuring platform 52 are electrically connected. The thermocouple 51 is a temperature sensor based on the thermoelectric effect, which can convert the temperature difference into an electrical signal output, and the thermocouple temperature measuring platform 52 is used to receive the electrical signal, process and display it, so as to obtain the temperature change of the absorber when receiving chiral light irradiation. The thermocouple 51 has the advantages of high sensitivity, fast response speed and wide measurement range, and is suitable for accurately measuring the weak thermal signal generated by the absorber. The thermocouple temperature measuring platform 52 can also be integrated with a data acquisition and processing system to facilitate real-time recording and analysis of the measurement results.

[0074] In a feasible embodiment, the thermal detection system further includes a camera 61 module, which is arranged corresponding to the optomechanical module 40; the camera 61 module is used to obtain image information of the absorber through the optomechanical module 40 to adjust the position of the absorber based on the image information.

[0075] In this embodiment, the camera 61 module may include a camera 61 and a terminal device 62, and the camera 61 and the terminal device 62 are electrically connected. In this embodiment, the camera 61 may be a CCD camera, and the terminal device 62 may be an electronic device with image processing function such as a computer. The camera 61 is arranged corresponding to the optical-mechanical module 40, and is used to capture the image information of the light processed by the optical-mechanical module 40 and irradiated onto the absorber, and the terminal device 62 is used to receive and display the image information captured by the camera 61. By observing the image information on the display terminal, the operator can intuitively understand the actual state of the absorber, such as whether the absorber is located at the center of the light spot, and whether the surface of the absorber is flat. If it is found that there is a deviation in the position of the absorber or the surface is uneven, the operator can adjust the position of the absorber in time to ensure the accuracy of the measurement.

[0076] In one possible implementation, reference Figure 4 The thermal detection system further includes a rotating platform, on which the polarizer 42 and / or the quarter glass 43 are arranged to control the direction of the circularly polarized light by driving the polarizer 42 and / or the quarter glass 43 to rotate.

[0077] In this embodiment, the rotating platform includes a rotating platform body 71, a fixture 72, and a turntable 73. The turntable 73 is mounted on the rotating platform body 71. The fixture 72 is mounted on the rotating platform body 71. One end of the fixture 72 is rotatably connected to the turntable 73, and the other end is rotatably connected to the polarizer 42 and / or the quarter glass 43. By driving the turntable 73 to rotate, the polarizer 42 and the quarter glass 43 can be driven to rotate synchronously, thereby changing the optical axis direction of the linearly polarized light and the handedness of the circularly polarized light, thereby achieving chiral light irradiation of the absorber in different directions. Optionally, the turntable 73 is provided with an angle scale to facilitate precise control of the rotation angle of the polarizer 42 and the quarter glass 43, thereby achieving precise control of chiral light irradiation of the absorber in different directions.

[0078] In a feasible embodiment, the operating wavelengths corresponding to the microscope objective lens 44, quarter-wave plate, and polarizer 42 all include the absorption peak wavelength of the absorber determined after testing the absorption spectrum of the absorber, so as to ensure that the performance of these optical components matches the absorption characteristics of the absorber, thereby generating the best surface plasmon effect and thermal signal output under chiral light irradiation to improve the accuracy and stability of the thermal detection system in identifying chiral substances.

[0079] This application also proposes a method for identifying chiral substances, which is based on the thermal detection system. Figure 5 The method includes steps S100 to S600, wherein:

[0080] Step S100: preparing the chiral substance to be tested into a corresponding solution to be tested.

[0081] In this embodiment, since the chiral substance to be tested needs to be configured as a corresponding solution to be tested, the chiral substance to be tested is a chiral substance soluble in water or other solvents. Figure 6 , the sample of the chiral substance to be tested can be first dissolved in the corresponding solvent, and its concentration can be configured according to actual needs to ensure that the concentration of the chiral substance in the test solution is appropriate (for example, 5 mg / ml, 6 mg / ml, etc.), and then it is fully mixed and stirred to ensure that the sample of the chiral substance to be tested is completely dissolved in the corresponding solvent.

[0082] Step S200 , taking a sample from the solution to be tested and placing it in the absorber, and placing the absorber in the thermal detection system.

[0083] In this embodiment, reference Figure 6After the solution is thoroughly mixed and stirred, a sampling operation is performed. A rubber-tipped dropper is used to draw a sample of the thoroughly mixed solution and drip it onto the surface of the absorber. The solution should be ensured to completely cover the absorber. The sample is then allowed to stand for a period of time to allow the solution to be fully absorbed by the absorber. Finally, absorbent paper is used to remove any remaining solution. The absorber covered with the solution to be tested is then placed on the stage 30 of the thermal detection system. The camera 61 and the associated terminal device 62 are used to observe whether the microscope field of view covers the area to be tested, whether the absorber is in the center of the field of view, and whether the absorber outline is clear. Otherwise, the position of the absorber is adjusted based on the fine-tuning mechanism of the stage 30.

[0084] In step S300, the laser light source 20 is turned on to emit laser light, and the optical machine module 40 is controlled to convert the laser light into chiral light with circular polarization in a first direction, the position of the absorber is adjusted so that the light spot of the chiral light is in the metal resonance layer 14, and the first temperature change data of the absorber is continuously obtained within a first preset time period based on the temperature measurement component, and then the laser light source 20 is turned off.

[0085] In this embodiment, the laser is turned on to emit laser light at a wavelength adapted to the absorber. At the same time, by controlling the rotation angle of the turntable 73, the polarizer 42 and the quarter glass 43 are synchronously rotated to convert the laser light into chiral light of circular polarization in the first direction. The position of the absorber is adjusted based on the fine adjustment mechanism of the stage 30 so that the light spot of the chiral light is located in the metal resonance layer 14 (refer to Figure 8 (left) The temperature measurement component continuously acquires first temperature change data of the absorber for a first preset duration, and then the laser light source 20 is turned off. In this embodiment, the chiral light of the first circularly polarized light can be left-handed circularly polarized light or right-handed circularly polarized light. The first preset duration can be set according to actual needs, for example, to 60 seconds, 80 seconds, or longer, to ensure that the temperature measurement component can accurately acquire the temperature change of the absorber when receiving chiral light.

[0086] In step S400, the laser light source 20 is turned on to emit laser light, and the optical machine module 40 is controlled to convert the laser light into chiral light of a second direction circularly polarized light, the position of the absorber is adjusted so that the light spot of the chiral light is in the metal resonance layer 14, and the second temperature change data of the absorber is continuously obtained within a first preset time period based on the temperature measurement component, and then the laser light source 20 is turned off.

[0087] In this embodiment, the laser is turned on to emit laser light at a wavelength adapted to the absorber. At the same time, by controlling the rotation angle of the turntable 73, the polarizer 42 and the quarter glass 43 are synchronously rotated to convert the laser light into chiral light of the second direction circularly polarized light. The position of the absorber is adjusted based on the fine adjustment mechanism of the stage 30 so that the light spot of the chiral light is located on the metal resonant layer 14 (refer to Figure 8 (left) The temperature measurement component continuously acquires first temperature change data of the absorber for a first preset duration, and then the laser light source 20 is turned off. In this embodiment, the chiral light of the second circularly polarized light can be left-handed or right-handed, as long as it is in the opposite direction of the first circularly polarized light. The first preset duration can be set according to actual needs, for example, to 60 seconds, 80 seconds, or longer, to ensure that the temperature measurement component can accurately acquire the temperature change of the absorber when receiving chiral light.

[0088] Step S500: Calculate a photothermal CD value based on the first temperature change data and the second temperature change data.

[0089] In this embodiment, the photothermal CD value can be calculated by subtracting the temperature rise value detected under right circularly polarized light from the temperature rise value detected under left circularly polarized light.

[0090] It's understandable that the heat generated by surface plasmon micro- and nanostructures after photon absorption varies over different timescales. When light strikes a metal surface with a strong plasmon effect, it stimulates collective oscillations of surface electrons. At this point, the enhanced field within the micro- and nanostructure can be hundreds of times stronger than the original field, strongly absorbing the incident light energy. Within an extremely short timescale, approximately 5 to 20 femtoseconds, surface plasmons rapidly decay through electron-electron scattering, surface-electron scattering, and radiation damping. During this process, high-energy electrons are excited and rapidly diffuse through the structure at the Fermi velocity. Within approximately 100 femtoseconds, the kinetic energy of these high-energy electrons is redistributed among electrons throughout the structure. Subsequently, over a period of 100 femtoseconds to 1 picosecond, the electrons' energy undergoes a redistribution process, primarily through electron-electron scattering. These electrons then transfer their energy to the crystal lattice, a process that takes approximately a few picoseconds. Finally, within a time period of 100 picoseconds to 10 nanoseconds, this energy will be gradually released into the surrounding environment in the form of heat energy, thus completing the entire energy dissipation process.

[0091] As mentioned above, by analyzing the relaxation process of surface plasmons at different time scales, it can be seen that the conversion of light energy into thermal energy mainly depends on the local electric field enhancement and light absorption process of surface plasmon micro-nanostructures. Figure 10The heat generation process of plasmon relaxation on the sensor surface and the corresponding time domains (A)–(D) are (t=0s), (t=1–100fs), (t=100fs–1ps), and (t=100ps–10ns), respectively. Materials with strong plasmon effects, such as gold and silver, have stronger thermal conductivity than surrounding ordinary media. This allows the heat generated within them to be transferred to the surrounding area at a very fast rate, resulting in a nearly uniform internal temperature. Therefore, the photothermal CD (CD) of different chiral materials using the same laser and the same chiral metamaterial structure varies. The type, chirality, and concentration of the chiral material all affect the specific photothermal CD value. Therefore, we can identify the type, chirality, and concentration of the chiral material based on the different photothermal CDs.

[0092] Step S600 : comparing the photothermal CD value with preset reference data to obtain an identification result of the chiral substance.

[0093] In this embodiment, by comparing the calculated photothermal CD value with a preset threshold value in the reference data, the type, chirality, and concentration of the chiral substance to be tested can be determined. The reference data can be obtained based on a large amount of experimental data and trained and optimized by a machine learning algorithm to improve the accuracy and reliability of identification. In practical applications, appropriate reference data can be selected for comparison based on the specific circumstances and needs of the chiral substance to be tested. If the calculated photothermal CD value matches or is close to a certain threshold value in the reference data, it can be considered that the chiral substance to be tested has the same type, chirality, and concentration as the corresponding reference data.

[0094] In one possible implementation, reference Figure 7 Before step S500, the method further includes:

[0095] In step S700, the laser light source 20 is turned on to emit laser light, and the optical machine module 40 is controlled to convert the laser light into chiral light of circularly polarized light in a first direction, the position of the absorber is adjusted so that the light spot of the chiral light is not in the metal resonance layer 14, and the third temperature change data of the absorber is obtained within a first preset time period based on the temperature measurement component, and then the laser light source 20 is turned off.

[0096] In this embodiment, the laser is turned on to emit laser light at a wavelength adapted to the absorber. At the same time, by controlling the rotation angle of the turntable 73, the polarizer 42 and the quarter glass 43 are synchronously rotated to convert the laser light into chiral light of circular polarization in the first direction. The position of the absorber is adjusted based on the fine adjustment mechanism of the stage 30 so that the light spot of the chiral light is not located in the metal resonance layer 14. (Refer to Figure 8(right) The temperature measurement component continuously acquires first temperature change data of the absorber for a first preset duration, and then the laser light source 20 is turned off. In this embodiment, the chiral light of the first circularly polarized light can be left-handed circularly polarized light or right-handed circularly polarized light. The first preset duration can be set according to actual needs, for example, to 60 seconds, 80 seconds, or longer, to ensure that the temperature measurement component can accurately acquire the temperature change of the absorber when receiving chiral light.

[0097] In step S800, the laser light source 20 is turned on to emit laser light, and the optical machine module 40 is controlled to convert the laser light into chiral light of circularly polarized light in a second direction, the position of the absorber is adjusted so that the light spot of the chiral light is not in the metal resonance layer 14, and the fourth temperature change data of the absorber is obtained within the first preset time period based on the temperature measurement component, and then the laser light source 20 is turned off.

[0098] In this embodiment, the laser is turned on to emit laser light at a wavelength adapted to the absorber. At the same time, by controlling the rotation angle of the turntable 73, the polarizer 42 and the quarter glass 43 are synchronously driven to rotate to convert the laser light into chiral light of the second direction circularly polarized light. The position of the absorber is adjusted based on the fine adjustment mechanism of the stage 30 so that the light spot of the chiral light is not located in the metal resonance layer 14. (Refer to Figure 8 (right) The temperature measurement component continuously acquires first temperature change data of the absorber for a first preset duration, and then the laser light source 20 is turned off. In this embodiment, the chiral light of the second circularly polarized light can be left-handed or right-handed, as long as it is in the opposite direction of the first circularly polarized light. The first preset duration can be set according to actual needs, for example, to 60 seconds, 80 seconds, or longer, to ensure that the temperature measurement component can accurately acquire the temperature change of the absorber when receiving chiral light.

[0099] In this embodiment, by acquiring third and fourth temperature change data when the chiral light spot is not located within the metal resonant layer 14, the first and second temperature change data can be used as controls, further improving the accuracy and reliability of the photothermal CD value calculation. In practice, the control group is the experimental group without any chiral substance added, and the photothermal CD value calculated based on the control group data remains nearly zero.

[0100] In a feasible embodiment, before step S500, the method further includes executing step S300, step S400, step S700 and step S800 multiple times respectively to reduce errors in the acquired first temperature change data, second temperature change data, third temperature change data and fourth temperature change data.

[0101] In this embodiment, in order to reduce random errors and systematic errors, each set of experimental data is repeatedly measured and the average value is taken as the final result. In addition, statistical methods can be used to analyze the data to further determine the reliability and accuracy of the data. Through this method, it is possible to ensure that the first temperature change data, the second temperature change data, the third temperature change data, and the fourth temperature change data obtained have a high degree of accuracy and reliability, thereby providing strong support for subsequent photothermal CD value calculation and chiral substance identification.

[0102] In a feasible embodiment, before the laser light source 20 is turned on each time, the absorber is kept at an initial temperature at which no surface plasmon effect is generated.

[0103] In this embodiment, since the heat energy generated by the surface plasmon effect will affect the temperature of the absorber, thereby affecting the subsequent temperature change data measurement, the absorber is maintained at an initial temperature where no surface plasmon effect is generated before the laser light source 20 is turned on each time. Specifically, the absorber can be cooled for a preset second time period after each step S300, step S400, step S700 or step S800 is executed. For example, the preset second time period can be 30 seconds, 45 seconds or longer to ensure that the absorber can be fully cooled to the initial temperature. The cooling process can be carried out by natural cooling or based on a cooling device integrated in the stage 30, depending on the experimental conditions and requirements. In this way, it can be ensured that the temperature of the absorber is consistent at the beginning of each experiment, thereby eliminating the influence of temperature factors on the experimental results and improving the accuracy and repeatability of the experiment.

[0104] In one embodiment, four solutions of the chiral substance to be tested are prepared, which are 10 ml of 85% L-lactic acid solution, and 32.5 ml, 11.25 ml, 4.17 ml, and 0.63 ml of synthetic deionized water are prepared respectively, and then added to the four L-lactic acid solutions to be tested, and the mixture is thoroughly mixed with a stirring rod to prepare 20%, 40%, 60%, and 80% L-lactic acid solutions. The steps of the chiral substance identification method of the present application are respectively performed as the test solutions, and the corresponding photothermal CD values ​​are obtained. Figure 11 The final photothermal CD value can be compared with the experimental group to confirm the approximate concentration range. For example, if the photothermal CD value of an L-lactic acid solution of unknown concentration is 0.9 degrees Celsius after testing, it can be roughly confirmed that its concentration is about 60%.

[0105] In another embodiment, eight portions of 1 ml of deionized water for synthesis and 5 mg each of the chiral substances to be tested were prepared: L-lactic acid, D-lactic acid, L-ribose, D-ribose, L-cysteine, L-cysteine ​​hydrochloride hydrate, L-malic acid, and L-xylose. Subsequently, each chiral substance to be tested was added to the deionized water and thoroughly mixed with a stirring rod to prepare various solutions with a concentration of 5 mg / ml. The solutions were used as test solutions to perform the steps of the chiral substance identification method of the present application, and the corresponding photothermal CD values ​​were obtained. Figure 12 The final photothermal CD value can be compared with the experimental group to confirm the type and chirality of the chiral substance to be tested. For example, if a 5 mg / ml concentration of unknown type and chirality test solution has a photothermal CD value of 1.4 degrees Celsius after testing, it can be roughly confirmed to be L-cysteine ​​hydrochloride hydrate.

[0106] The thermal detection system and chiral substance identification method disclosed in this application are based on the structure of the thermal detection system and the steps of the chiral substance identification method. By configuring the chiral substance to be detected into a corresponding test solution, sampling the test solution and placing it in an absorber, and utilizing the surface plasmon effect generated when the metal resonant layer 14 receives chiral light irradiation, a corresponding thermal signal is output. The thermal signal is then captured and analyzed by the thermal detection system, achieving high-precision identification of chiral substances. Compared with traditional circular dichroism and circularly polarized fluorescence spectrometers, the technical solution of this application has a simple structure, is easy to operate, and has lower requirements for the concentration and volume of the test sample.

[0107] The above description is only part of the embodiments of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made by using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for identifying chiral substances, characterized in that: The method is based on a heat detection system comprising: A laser light source, used for emitting laser light; a stage for carrying the absorber; an optical-mechanical module, disposed correspondingly to the laser light source and the stage, respectively; the optical-mechanical module is configured to convert the laser light emitted by the laser light source into chiral light and output the chiral light to the stage, so that the absorber carried by the stage outputs a corresponding heat signal when receiving the chiral light; a temperature measuring component, disposed corresponding to the stage, and configured to receive the thermal signal to obtain a corresponding temperature; The absorber comprises: substrate layer; a bottom metal layer, the bottom metal layer being disposed on one side of the substrate layer; a dielectric layer, the dielectric layer being disposed on a side of the bottom metal layer away from the substrate layer; a metal resonance layer, the metal resonance layer being disposed on a side of the dielectric layer away from the bottom metal layer, the metal resonance layer being configured to generate a surface plasmon effect and output a corresponding thermal signal when irradiated by chiral light; The method comprises: Step S100, preparing the chiral substance to be tested into a corresponding test solution; Step S200, taking a sample from the solution to be tested and placing it in the absorber, and placing the absorber in the thermal detection system; Step S300: Turning on the laser light source to emit laser light, controlling the optical-mechanical module to convert the laser light into chiral light having circular polarization in a first direction, adjusting the position of the absorber so that the chiral light spot is located in the metal resonant layer, and continuously acquiring first temperature change data of the absorber for a first preset time period based on the temperature measurement component, and then turning off the laser light source; Step S400: Turning on the laser light source to emit laser light, controlling the optical-mechanical module to convert the laser light into chiral light having a second circularly polarized direction, adjusting the position of the absorber so that the chiral light spot is located in the metal resonant layer, and continuously acquiring second temperature change data of the absorber for a first preset time period based on the temperature measurement component, and then turning off the laser light source; Step S500, calculating a photothermal CD value based on the first temperature change data and the second temperature change data; Step S600, comparing the photothermal CD value with preset reference data to obtain an identification result of the chiral substance; Before step S500, the method further includes: Step S700: Turning on the laser light source to emit laser light, controlling the optical-mechanical module to convert the laser light into chiral light having circular polarization in a first direction, adjusting the position of the absorber so that the chiral light spot is not located in the metal resonant layer, obtaining third temperature change data of the absorber within a first preset time period based on the temperature measurement component, and then turning off the laser light source; Step S800, turn on the laser light source to emit laser, and control the optical machine module to convert the laser into chiral light with circular polarization in the second direction, adjust the position of the absorber so that the light spot of the chiral light is not in the metal resonance layer, and obtain the fourth temperature change data of the absorber within the first preset time period based on the temperature measurement component, and then turn off the laser light source.

2. The method for identifying a chiral substance according to claim 1, wherein: Before step S500, the method further includes: The steps S300 , S400 , S700 and S800 are respectively performed multiple times to reduce errors in the acquired first temperature change data, second temperature change data, third temperature change data and fourth temperature change data.

3. The method for identifying a chiral substance according to claim 2, wherein: Before turning on the laser light source each time, the absorber is kept at an initial temperature at which no surface plasmon effect is generated.

4. A thermal detection system for implementing the chiral substance identification method according to any one of claims 1 to 3, characterized in that: The thermal detection system comprises: A laser light source, used for emitting laser light; a stage for carrying the absorber; an optical-mechanical module, disposed correspondingly to the laser light source and the stage, respectively; the optical-mechanical module is configured to convert the laser light emitted by the laser light source into chiral light and output the chiral light to the stage, so that the absorber carried by the stage outputs a corresponding heat signal when receiving the chiral light; a temperature measuring component, disposed corresponding to the stage, and configured to receive the thermal signal to obtain a corresponding temperature; The absorber comprises: substrate layer; a bottom metal layer, the bottom metal layer being disposed on one side of the substrate layer; a dielectric layer, the dielectric layer being disposed on a side of the bottom metal layer away from the substrate layer; a metal resonance layer, the metal resonance layer being disposed on a side of the dielectric layer away from the bottom metal layer, the metal resonance layer being configured to generate a surface plasmon effect and output a corresponding thermal signal when irradiated by chiral light; The detection system further includes a camera module, which is arranged corresponding to the optomechanical module; the camera module is used to obtain image information of the absorber through the optomechanical module, so as to adjust the position of the absorber based on the image information.

5. The heat detection system according to claim 4, wherein: The optical-mechanical module comprises: a half-reflecting half-mirror lens, disposed corresponding to the laser light source, configured to reflect a portion of the laser light emitted by the laser light source to enter the camera module, and transmit another portion of the laser light emitted by the laser light source to illuminate the absorber; a polarizer, arranged corresponding to the half-reflecting half-mirror lens, for converting the laser light transmitted by the half-reflecting half-mirror lens into linearly polarized light; a quarter glass plate, arranged corresponding to the polarizer, for converting the linearly polarized light into circularly polarized light; A microscope objective lens is respectively arranged corresponding to the quarter glass slide and the stage, and is used to focus the circularly polarized light on the absorber surface of the stage.

6. The heat detection system according to claim 5, wherein: The thermal detection system further comprises: A rotating platform is provided on which the polarizer and / or the quarter glass are arranged so as to control the direction of the circularly polarized light by driving the polarizer and / or the quarter glass to rotate.

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