Molecular luminous force transient dynamics detection system

Abstract

The invention provides a molecule luminous force transient dynamics detection system. The molecule luminous force transient dynamics detection system comprises a laser generation assembly, a beam splitter, a first lens, a nonlinear crystal, a second lens, an optical parameter amplifier, a delayer, a first gathering system, a second gathering system and a microscopic optical imaging device, wherein the first gathering system is used for focusing the mid-infrared pump light on the back surface of a sample to be detected, the second gathering system is used for focusing the visible detection light on the front surface of the sample to be detected, and Raman scattering light is collected through the microscopic optical imaging device; the delayer adjusts the optical path of the visible detection pulse laser focused by the second lens and controls the time delay of the pumping and detection light reaching a sample, so that a dynamic detection system with the time resolution being less than 1ps can be realized, a good test platform is provided for a transient process, and nonlinear up-conversion transient dynamic process detection of a molecular light force system is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of molecular photodynamic transient dynamics detection, and in particular relates to a molecular photodynamic transient dynamics detection system. Background Art

[0002] Compared with up-conversion detectors, most mid-infrared detectors on the market currently have problems such as low sensitivity, slow response speed and high price, which make them difficult to be used in high temperature or complex environments, meet the needs of rapid dynamic monitoring, and large-scale industrial production. Among them, converting mid-infrared light into visible light and then indirectly obtaining infrared information with the help of high-performance up-conversion detectors is a feasible solution. However, traditional mid-infrared up-conversion requires the combination of infrared light and visible light, which needs to meet momentum matching conditions and involves complex and difficult optical path and material design, which is not conducive to its wide application.

[0003] The molecular photomechanical system proposed based on surface enhanced Raman scattering technology has the advantages of simple device preparation, high photomechanical coupling coefficient, high operating frequency, and room temperature operation, and has attracted widespread attention in recent years. The molecular photomechanical coupling effect extends to mid-infrared upconversion detection, using molecules as upconversion media to convert mid-infrared signal light into molecular vibration modes, which are further coupled with visible pump light and upconverted to the visible light band through Raman scattering. No momentum matching is required, which greatly simplifies the complexity of the system and shows many advantages such as fast response speed and strong anti-interference ability. Combined with mature visible light detection devices, this technology can significantly reduce the cost of infrared detection and is expected to promote widespread application in this field.

[0004] However, there are several limitations in the current research on molecular photomechanical upconversion technology. First, although the quantum efficiency of the upconversion process of the molecular photomechanical system based on surface-enhanced Raman technology has been improved, its upconversion efficiency is still limited due to the small Raman scattering cross section. How to further improve its quantum efficiency has become an urgent problem to be solved; secondly, the current research on molecular photomechanical technology adopts a low-power continuous light irradiation scheme, and lacks research on nonlinear scattering phenomena of high-power irradiation, such as the nonlinear enhancement of anti-Stokes scattering with increasing power, the reduction of scattering spectrum broadening, parameter instability, giant light spring effect, collective vibration mode, etc.; in addition, at high peak power, the upconversion process will have extremely complex dynamic processes, and its Raman scattering population lifetime, nonlinear upconversion transient dynamics, and the study of deep nonlinear scattering mechanisms are all to be solved.

[0005] In view of the current research needs of exploring the nonlinear upconversion mechanism of molecular photomechanics under high peak power irradiation, the traditional molecular photomechanics continuous light irradiation and steady-state test system can no longer meet the measurement needs. It is of great significance to study the pump-probe measurement technology that can integrate high irradiation peak power, ultrafast time resolution, and nonlinear enhancement to meet the needs of detecting transient dynamics of molecular photomechanics at room temperature, and can ensure that the molecular photomechanics system can successively perform infrared absorption and Raman upconversion.

[0006] Based on the technical problems existing in the above-mentioned molecular photodynamic system, there is no relevant solution yet; therefore, there is an urgent need to find effective solutions to solve the above-mentioned problems. Summary of the invention

[0007] The purpose of the present invention is to address the deficiencies in the above-mentioned technologies and propose a molecular photodynamic transient dynamics detection system, aiming to solve the problem of detecting nonlinear up-conversion transient dynamics processes in existing molecular photodynamic systems.

[0008] The invention provides a molecular light force transient dynamics detection system, which comprises a laser generating component, a beam splitter, a first lens, a nonlinear crystal, a second lens, an optical parametric amplifier, a delay device, a first focusing system, a second focusing system and a microscopic optical imaging device; the laser generating component is used to generate pulse laser; the beam splitter is used to reflect the pulse laser and transmit the pump pulse laser; the first lens is used to focus the pulse laser reflected by the beam splitter; the nonlinear crystal is used to excite the monochromatic light focused by the first lens to generate supercontinuum white light pulses; the second lens is used to focus the visible pulse laser emitted by the nonlinear crystal; the optical parametric amplifier is used to adjust the wavelength of the pulse laser reflected by the beam splitter and generate mid-infrared pump light; the first focusing system is arranged at the back of a sample to be tested and is used to focus the mid-infrared pump light on the back of the sample to be tested; the second focusing system is arranged at the front of the sample to be tested and is used to focus the visible detection light on the front of the sample to be tested; the delay device is used to adjust the optical path of the visible pulse laser focused by the second lens and incident on the front of the sample to be tested through the second focusing system; the microscopic optical imaging device is used to collect Raman scattering signal light scattered by the sample to be tested.

[0009] Further, the first focusing system is a first microscope objective lens, and the second focusing system is a second microscope objective lens.

[0010] Furthermore, the first microscope objective lens and the second microscope objective lens are of exactly the same model.

[0011] Furthermore, the sample to be tested is arranged between the first microscope objective lens and the second microscope objective lens; during the detection process, the first microscope objective lens and the second microscope objective lens are moved simultaneously or the first microscope objective lens and the second microscope objective lens are kept stationary, and the position of the sample to be tested is moved laterally, so that the mid-infrared pump light and the visible detection light are cofocused at different positions of the molecular photodynamic system.

[0012] Furthermore, the optical parametric amplifier is used to adjust the wavelength of the pump pulse laser, thereby generating mid-infrared pump light of corresponding frequency that matches the specific infrared absorption mode of the molecular photomechanical system.

[0013] Furthermore, the molecular optical force system is a molecular optical force nanocavity system composed of a composite of gold nanoparticles and nanogrooves; or, the molecular optical force system is a Rydberg exciton state molecular optical force system based on two-dimensional TMD materials; or, the molecular optical force system is a nanomolecular optical force system of metal mirror-material-particle sphere.

[0014] Furthermore, the first lens and the second lens are of exactly the same model.

[0015] Furthermore, a movable thin film beam splitter is provided on the microscopic optical imaging device; when observing the detection area of ​​the sample to be tested before detection, the thin film beam splitter is placed in the light path to observe the surface of the sample to be tested and align the light path, and after determining the detection area of ​​the sample to be tested, the thin film beam splitter is moved out of the light path for detection.

[0016] Furthermore, the microscopic optical imaging device is a spectrometer or a CCD; the spectrometer or the CCD collects the spectrum of the Raman scattered signal light.

[0017] Furthermore, the delay device controls the time delay between the pump light and the detection light reaching the sample by adjusting the optical path of the pulsed laser focused by the second lens.

[0018] Compared with the prior art, the solution provided by the present invention has the following advantages:

[0019] 1. The molecular photoforce transient dynamics detection system provided by the present invention adopts a high-peak power pulsed laser as a light source, replacing the current continuous light irradiation scheme. The advantage is that it uses picosecond or even femtosecond pulsed light irradiation, and can study the nonlinear scattering phenomenon of the molecular photoforce system under high peak power without burning the sample. This method can further gain a deeper understanding of the new nonlinear mechanisms and mechanisms of the molecular photoforce system.

[0020] 2. The molecular photoforce transient dynamics detection system provided by the present invention uses an improved pump-detection technology of back-pumping and front-detection, and uses a delay device to adjust the optical path of the visible detection light. By adjusting the delay device, the time when the mid-infrared pump light and the visible detection light arrive at the molecular photoforce system in sequence is controlled. The state of the molecular photoforce system under different time delays can be detected, and then the dynamic process of the molecular photoforce system and the Raman scattering population lifetime of the system can be explored, and the nonlinear up-conversion mechanism of the molecular photoforce system can be deeply understood, providing a theoretical basis for significantly improving the mid-infrared up-conversion efficiency.

[0021] 3. The molecular photoforce transient dynamics detection system provided by the present invention uses a molecular photoforce system to perform mid-infrared upconversion on the sample to be tested, avoiding the defects of traditional mid-infrared upconversion detectors, because the combination of infrared light and visible light requires momentum matching conditions, which involves complex and difficult optical path and material design. The molecular photoforce system of the present application has the advantages of simple system, high sensitivity, fast response speed, strong anti-interference ability, and low cost for mid-infrared upconversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0023] The present invention will be further described below in conjunction with the accompanying drawings:

[0024] Figure 1 This is a schematic diagram of a molecular photoforce transient dynamics detection system of the present invention.

[0025] In the figure: 1. Laser generating assembly; 2. Beam splitter; 3. First lens; 4. Nonlinear crystal; 5. Second lens; 6. Optical parametric amplifier; 7. Delay device; 8. First microscope objective lens; 9. Sample to be measured; 10. Second microscope objective lens; 11. Microscopic optical imaging device. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0028] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0029] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] like Figure 1As shown, the present invention provides a molecular photoforce transient dynamics detection system, which belongs to the field of ultrafast dynamics detection, and relates to a molecular photoforce transient dynamics detection system based on back pumping and front detection, which is particularly suitable for the study of molecular photoforce coupling effect, molecular photoforce induced transparency, Raman scattering population lifetime, and especially the transient dynamics process of nonlinear upconversion. Specifically, the detection system includes a laser generating component 1, a beam splitter 2, a first lens 3, a nonlinear crystal 4, a second lens 5, an optical parametric amplifier 6, a delay device 7, a first focusing system, a second focusing system and a microscopic optical imaging device 11. The laser generating component 1 is a pulse laser, which is used to generate pulse laser; the beam splitter 2 is used to reflect the pulse laser and transmit the pump pulse laser; the first lens 3 is used to focus the pulse laser reflected by the beam splitter 2; the nonlinear crystal 4 is used to excite the monochromatic light focused by the first lens 3 to generate supercontinuum white light pulses; the second lens 5 is used to focus the visible pulse laser emitted by the nonlinear crystal 4; the optical parametric amplifier 6 is used to adjust the wavelength of the pulse laser reflected by the beam splitter 2 and generate mid-infrared pump light. The first focusing system is arranged on the back of the sample to be tested 9, and is used to focus the mid-infrared pump light on the back of the sample to be tested 9; the second focusing system is arranged on the front of the sample to be tested 9, and is used to focus the visible detection light on the front of the sample to be tested 9; the delay device 7 is used to adjust the optical path of the visible pulse laser focused by the second lens 5, and is incident on the front of the sample to be tested 9 through the second focusing system 10, and its function is to change the optical path of the visible detection light, so that it arrives at the sample slower than the mid-infrared pump light in time, so as to achieve the function of dynamic detection. The microscopic optical imaging device 11 is used to collect the Raman scattered signal light scattered by the sample to be tested 9. The present invention injects the mid-infrared pump light from the back of the sample to be tested, and injects the visible detection light forwardly. The detection light is backscattered by the sample, and the Raman scattered light is collected by the objective lens, and finally the spectrum is collected by the spectrometer or CCD. By controlling the time delay between the pump and probe light reaching the sample through a delay line, a dynamic detection system with a time resolution of less than 1ps can be realized, providing a good testing platform for studying the transient dynamics of nonlinear upconversion and exploring transient processes such as molecular photoinduced transparency and Raman scattering population lifetime.

[0032] In response to the technical problems existing in the prior art, the molecular photoforce transient dynamics detection system provided by the present invention replaces the previous continuous light irradiation with a pulsed laser with high peak power irradiation, which can study the nonlinear scattering phenomenon of molecular photoforce under high power. At the same time, it adopts the pump-probe measurement technology with ultra-high time resolution to realize the detection of the nonlinear up-conversion transient dynamics process of the molecular photoforce system.

[0033] Preferably, in combination with the above scheme, Figure 1As shown, the first focusing system is the first microscope objective 8, the second focusing system is the second microscope objective 10, and the first microscope objective 8 and the second microscope objective 10 are of exactly the same model, which can greatly eliminate the system error of the optical path, so that the mid-infrared pump light and the visible detection light are co-focused to the same position of the molecular optical force system. Specifically, the mid-infrared pump light is incident on the back of the sample 9 through the first microscope objective 8, and the visible detection light is incident on the front of the sample 9 through the second microscope objective 10; the mid-infrared pump light and the visible detection light are converted into Raman scattered light, so that the microscopic optical imaging device 11 collects the Raman scattered light.

[0034] Preferably, in combination with the above scheme, Figure 1 As shown, the sample 9 to be tested is disposed between the first microscope objective lens 8 and the second microscope objective lens 10. Specifically, during the detection process, the first microscope objective lens 8 and the second microscope objective lens 10 are moved simultaneously or the first microscope objective lens 8 and the second microscope objective lens 10 are kept stationary, and the position of the sample 9 to be tested is moved laterally, so that the mid-infrared pump light and the visible detection light are cofocused to different positions of the molecular photomechanical system.

[0035] Preferably, in combination with the above scheme, Figure 1 As shown, the optical parametric amplifier 6 is used to adjust the wavelength of the pump pulse laser in the range of 470 to 2600 nm, thereby generating mid-infrared pump light of corresponding frequency that matches the specific infrared absorption mode of the molecular photodynamic system, thereby greatly enhancing the infrared absorption efficiency of the molecular photodynamic system and further improving the mid-infrared upconversion efficiency.

[0036] Preferably, in combination with the above scheme, Figure 1 As shown, the molecular optical force system is a molecular optical force nanocavity system composed of a composite of gold nanoparticles and nanogrooves; or, the molecular optical force system is a Rydberg exciton state molecular optical force system based on two-dimensional TMD materials; or, the molecular optical force system is a nanomolecular optical force system of metal mirror-material-particle sphere.

[0037] Preferably, in combination with the above scheme, Figure 1 As shown, the first lens 3 and the second lens 5 are of exactly the same model, which can greatly eliminate the system error of the optical path and make the mid-infrared pump light and the visible detection light cofocus at the same position of the molecular photodynamic system.

[0038] Preferably, in combination with the above scheme, Figure 1 As shown, a movable thin film beam splitter is provided on the microscopic optical imaging device 11; when observing the detection area of ​​the sample to be tested 9 before detection, the thin film beam splitter is placed in the light path to observe the surface of the sample to be tested 9 and align the light path, and after determining the detection area of ​​the sample to be tested 9, the thin film beam splitter is moved out of the light path for detection.

[0039] Preferably, in combination with the above scheme, Figure 1 As shown, the microscopic optical imaging device 11 is a spectrometer or a CCD; the spectrometer or the CCD collects the spectrum of the Raman scattered signal light.

[0040] Preferably, in combination with the above scheme, Figure 1 As shown, the delay device 7 controls the time delay of the pump and detection lights reaching the sample by adjusting the optical path of the pulsed laser focused by the second lens 5, thereby realizing a dynamic detection system with a time resolution of less than 1 ps, and providing a good testing platform for studying the transient dynamic process of nonlinear up-conversion and exploring transient processes such as molecular photoinduced transparency and Raman scattering population lifetime.

[0041] like Figure 1 As shown, the molecular photoforce transient dynamics detection system provided by the present invention can detect the state of the molecular photoforce system under different time delays by adjusting the delay device 7 to change the optical path of the visible detection light, and control the time when the mid-infrared pump light and the visible detection light arrive at the molecular photoforce system respectively, and then explore the dynamic process of the molecular photoforce system and the Raman scattering population lifetime of the system, deeply understand the nonlinear up-conversion mechanism of the molecular photoforce system, and provide a theoretical basis for greatly improving the mid-infrared up-conversion efficiency.

[0042] like Figure 1 As shown, the molecular optical force transient dynamics detection system provided by the present invention can select different molecular optical force systems according to different influencing factors for improving the mid-infrared upconversion efficiency. In terms of structure, a molecular optical force nanocavity system composed of gold nanoparticles and nanogrooves that support both infrared and visible dual-band plasmon resonances can be selected. In terms of ground state exciton transition hybridization, the inefficient Raman scattering process is replaced by a more efficient electron interband transition (including exciton excitation and exciton recombination), which is expected to greatly improve the upconversion efficiency. In terms of nonlinearity, the Rydberg exciton state nonlinear coefficient is several orders of magnitude higher than that of the ground state exciton, which may greatly improve the mid-infrared upconversion efficiency. A Rydberg exciton state molecular optical force system based on two-dimensional TMD materials can be selected. In addition, a new direction - molecular optical force induced transparency - can be studied through the nano-molecular optical force system of metal mirror-material-particle ball.

[0043] Compared with the prior art, the solution provided by the present invention has the following advantages:

[0044] 1. The molecular photoforce transient dynamics detection system provided by the present invention adopts a high-peak power pulsed laser as a light source, replacing the current continuous light irradiation scheme. The advantage is that it uses picosecond or even femtosecond pulsed light irradiation, and can study the nonlinear scattering phenomenon of the molecular photoforce system under high peak power without burning the sample. This method can further gain a deeper understanding of the new nonlinear mechanisms and mechanisms of the molecular photoforce system.

[0045] 2. The molecular photoforce transient dynamics detection system provided by the present invention uses an improved pump-detection technology of back-pumping and front-detection, and uses a delay device to adjust the optical path of the visible detection light. By adjusting the delay device, the time when the mid-infrared pump light and the visible detection light arrive at the molecular photoforce system in sequence is controlled. The state of the molecular photoforce system under different time delays can be detected, and then the dynamic process of the molecular photoforce system and the Raman scattering population lifetime of the system can be explored, and the nonlinear up-conversion mechanism of the molecular photoforce system can be deeply understood, providing a theoretical basis for significantly improving the mid-infrared up-conversion efficiency.

[0046] 3. The molecular photoforce transient dynamics detection system provided by the present invention uses a molecular photoforce system to perform mid-infrared upconversion on the sample to be tested, avoiding the defects of traditional mid-infrared upconversion detectors, because the combination of infrared light and visible light requires momentum matching conditions, which involves complex and difficult optical path and material design. The molecular photoforce system of the present application has the advantages of simple system, high sensitivity, fast response speed, strong anti-interference ability, and low cost for mid-infrared upconversion.

[0047] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the above-mentioned technical content without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any changes, modifications, equivalent changes and modifications made to the above embodiments based on the technology of the present invention without departing from the content of the technical solution of the present invention belong to the protection scope of the present technical solution.

Claims

1. A molecular photodynamic transient dynamics detection system, characterized in that: The detection system comprises a laser generating assembly (1), a beam splitter (2), a first lens (3), a nonlinear crystal (4), a second lens (5), an optical parametric amplifier (6), a delay device (7), a first focusing system, a second focusing system and a microscopic optical imaging device (11); The laser generating component (1) is used to generate pulsed laser; The beam splitter (2) is used to reflect the pulse laser and transmit the pump pulse laser; The first lens (3) is used to focus the pulsed laser reflected by the beam splitter (2); The nonlinear crystal (4) is used to excite the monochromatic light focused by the first lens (3) to generate supercontinuum white light pulses; The second lens (5) is used to focus the visible pulse laser emitted by the nonlinear crystal (4); The optical parametric amplifier (6) is used to adjust the wavelength of the pulsed laser reflected by the beam splitter (2) and generate mid-infrared pump light; The first focusing system is arranged on the back side of the sample to be tested (9) and is used to focus the mid-infrared pump light on the back side of the sample to be tested (9); The second focusing system is arranged on the front side of the sample to be tested (9) and is used to focus the visible detection light on the front side of the sample to be tested (9); The delay device (7) is used to adjust the optical path of the visible pulse laser focused by the second lens (5), and the laser is incident on the front side of the sample to be tested (9) through the second focusing system (10); The microscopic optical imaging device (11) is used to collect Raman scattered signal light scattered by the sample to be tested (9).

2. The molecular photodynamic transient dynamics detection system according to claim 1, characterized in that: The first focusing system is a first microscope objective (8), and the second focusing system is a second microscope objective (10).

3. The molecular photodynamic transient dynamics detection system according to claim 2, characterized in that: The first microscope objective lens (8) and the second microscope objective lens (10) are of exactly the same model.

4. The molecular photodynamic transient dynamics detection system according to claim 2, characterized in that: The sample to be tested (9) is arranged between the first microscope objective lens (8) and the second microscope objective lens (10); during the detection process, the first microscope objective lens (8) and the second microscope objective lens (10) are moved simultaneously or the first microscope objective lens (8) and the second microscope objective lens (10) are kept stationary, and the position of the sample to be tested (9) is moved laterally, so that the mid-infrared pump light and the visible detection light are cofocused at different positions of the molecular photodynamic system.

5. The molecular photodynamic transient dynamics detection system according to claim 1, characterized in that: The optical parametric amplifier (6) is used to adjust the wavelength of the pump pulse laser, thereby generating mid-infrared pump light of a corresponding frequency that matches a specific infrared absorption mode of the molecular photomechanical system.

6. The molecular photodynamic transient dynamics detection system according to claim 5, characterized in that: The molecular optical force system is a molecular optical force nanocavity system composed of gold nanoparticles and nanogrooves; or, the molecular optical force system is a Rydberg exciton state molecular optical force system generated based on two-dimensional TMD materials; or, the molecular optical force system is a nanomolecular optical force system of metal mirror-material-particle ball.

7. The molecular photodynamic transient dynamics detection system according to claim 1, characterized in that: The first lens (3) and the second lens (5) are of exactly the same model.

8. The molecular photodynamic transient dynamics detection system according to claim 1, characterized in that: The microscopic optical imaging device (11) is provided with a movable thin film beam splitter; when observing the detection area of ​​the sample to be detected (9) before detection, the thin film beam splitter is placed in the light path to observe the surface of the sample to be detected (9) and align the light path; and after determining the detection area of ​​the sample to be detected (9), the thin film beam splitter is moved out of the light path for detection.

9. The molecular photodynamic transient dynamics detection system according to claim 1, characterized in that: The microscopic optical imaging device (11) is a spectrometer or a CCD; the spectrometer or the CCD performs spectrum collection on the Raman scattered signal light.

10. The molecular photodynamic transient dynamics detection system according to claim 1, characterized in that: The delay device (7) controls the time delay of the pump light and the detection light reaching the sample by adjusting the optical path of the pulsed laser focused by the second lens (5).

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