A molecular photodynamic transient dynamics detection system

Abstract

The present invention provides a molecular photoforce transient dynamics detection system, comprising a laser generating assembly, 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 first focusing system is used to focus mid-infrared pump light on the back of a sample to be tested, and the second focusing system is used to focus visible detection light on the front of the sample to be tested, and Raman scattered light is collected by the microscopic optical imaging device. The delay device controls the time delay between the pump and detection lights reaching the sample by adjusting the optical path of the visible detection pulse laser focused by the second lens, thereby realizing a dynamics detection system with a time resolution of less than 1 ps, providing a good testing platform for transient processes, and realizing the detection of nonlinear up-conversion transient dynamic processes of the molecular photoforce system.

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 to upconversion detectors, most mid-infrared detectors currently on the market suffer from lower sensitivity, slower response speeds, and higher prices, making them unsuitable for applications such as high-temperature or complex environments, rapid dynamic monitoring, and large-scale industrial production. Upconverting mid-infrared light into visible light and then indirectly acquiring infrared information with the help of high-performance upconversion detectors is a viable solution. However, traditional mid-infrared upconversion requires combining the infrared and visible light frequencies, meeting momentum matching requirements, and involves complex and difficult optical path and material design, hindering its widespread application.

[0003] Molecular photomechanical systems, based on surface-enhanced Raman scattering (SERS), have attracted widespread attention in recent years due to their advantages, including simple device fabrication, high photomechanical coupling coefficient, high operating frequency, and room-temperature operation. The molecular photomechanical coupling effect extends to mid-infrared upconversion detection. Using molecules as upconversion media, mid-infrared signal light is converted into molecular vibrational modes, which are then coupled with visible pump light and upconverted to the visible light band via Raman scattering. This eliminates the need for momentum matching, greatly simplifying system complexity and demonstrating numerous advantages, including fast response speed and strong anti-interference capabilities. Combined with established 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, it 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. Second, the current research on molecular photomechanical technology adopts a low-power continuous light irradiation scheme, and lacks research on nonlinear scattering phenomena under high-power irradiation, such as the nonlinear enhancement of anti-Stokes scattering with increasing power, the reduction of scattering spectrum broadening, parametric instability, giant light spring effect, collective vibration mode, etc. In addition, at high peak power, the upconversion process will exhibit extremely complex dynamic processes. Its Raman scattering population lifetime, nonlinear upconversion transient dynamics, and the study of deep nonlinear scattering mechanisms are all yet to be solved.

[0005] To address the current research needs for exploring the nonlinear upconversion mechanism of molecular photomechanics under high peak power irradiation, traditional continuous light irradiation and steady-state testing systems for molecular photomechanics are no longer able to meet measurement requirements. Research on pump-probe measurement technology that combines high peak power, ultrafast time resolution, and nonlinear enhancement to enable molecular photomechanical systems to sequentially perform infrared absorption and Raman upconversion is of great significance for detecting transient dynamics of molecular photomechanics at room temperature.

[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 upconversion transient dynamics processes in existing molecular photodynamic systems.

[0008] The present invention provides a molecular light force transient dynamics detection system, which includes a laser generating assembly, 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 assembly is used to generate pulsed laser light. The beam splitter is used to reflect the pulsed laser light and transmit pump pulsed laser light. The first lens is used to focus the pulsed laser light 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 pulsed laser light emitted by the nonlinear crystal. The optical parametric amplifier is used to adjust the wavelength of the pulsed laser light 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 pulsed laser light 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] Furthermore, 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 measured 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 measured 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 optomechanical 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 generated 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 and 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 photodynamic transient dynamics detection system provided by the present invention adopts a high-peak power pulsed laser as the light source, replacing the current continuous light irradiation scheme. The advantage is that it uses picosecond or even femtosecond pulsed light irradiation, which can study the nonlinear scattering phenomenon of the molecular photodynamic system under high peak power without burning the sample. This method further deepens the understanding of the new nonlinear mechanisms and mechanisms of the molecular photodynamic system.

[0020] 2. The molecular photodynamic 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 photodynamic system in sequence is controlled. The state of the molecular photodynamic system under different time delays can be detected, and then the dynamic process of the molecular photodynamic system and the Raman scattering population lifetime of the system can be explored, and the nonlinear upconversion mechanism of the molecular photodynamic system can be deeply understood, providing a theoretical basis for significantly improving the mid-infrared upconversion efficiency.

[0021] 3. The molecular photodynamic transient dynamics detection system provided by the present invention uses a molecular photodynamic system to perform mid-infrared upconversion on the sample being tested, avoiding the drawbacks of conventional mid-infrared upconversion detectors, which require momentum matching conditions for combining infrared and visible light, and involve complex and difficult optical path and material design. The molecular photodynamic system of the present application for mid-infrared upconversion offers advantages such as system simplicity, high sensitivity, fast response, strong anti-interference capabilities, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0023] The present invention will be further described below with reference to 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 with reference to 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 on” or “disposed on” another element, it may 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 may be directly connected to the other element or indirectly connected to the other element.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0029] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", etc., indicating directions or positional relationships, 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 expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and may encompass internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0031] like Figure 1As shown, the present invention provides a molecular photodynamic transient dynamics detection system, which belongs to the field of ultrafast dynamics detection and relates to a molecular photodynamic transient dynamics detection system based on back pumping and front detection. It is particularly suitable for studying the molecular photodynamic coupling effect, molecular photodynamic induced transparency, Raman scattering population lifetime, and especially the transient dynamics process of nonlinear upconversion. Specifically, the detection system includes 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 assembly 1 is a pulsed laser for generating pulsed laser light; the beam splitter 2 is used to reflect the pulsed laser light and transmit the pump pulse laser light; the first lens 3 is used to focus the pulsed laser light 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 pulsed laser light emitted by the nonlinear crystal 4; and the optical parametric amplifier 6 is used to adjust the wavelength of the pulsed laser light 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, which has the function of changing the optical path of the visible detection light so that it arrives at the sample slower than the mid-infrared pump light in time, thereby realizing 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 mid-infrared pump light from the back of the sample to be tested, injects visible detection light in the forward direction, and 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 a 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 achieved, 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 existing technology, 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 pump-probe measurement technology with ultra-high time resolution to realize the detection of nonlinear up-conversion transient dynamics process of molecular photoforce system.

[0033] Preferably, in combination with the above scheme, Figure 1As shown, the first focusing system is the first microscope objective 8, and the second focusing system is the second microscope objective 10. The first microscope objective 8 and the second microscope objective 10 are of exactly the same model. This can greatly eliminate the systematic error of the optical path, so that the mid-infrared pump light and the visible probe light are cofocused at the same position in the molecular photodynamic 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 probe light is incident on the front of the sample 9 through the second microscope objective 10; the mid-infrared pump light and the visible probe light are up-converted into Raman scattered light, so that the micro-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 measured 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 kept stationary, and the position of the sample 9 to be measured is shifted laterally, so that the mid-infrared pump light and the visible detection light are cofocused at different positions of the molecular photodynamic 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 thereby 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 generated 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 systematic error of the optical path and make the mid-infrared pump light and the visible detection light cofocus at the same position in 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 between the pump and probe light 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 dynamics of nonlinear upconversion 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 changes the optical path of the visible detection light by adjusting the delay device 7, and controls the time when the mid-infrared pump light and the visible detection light arrive at the molecular photoforce system respectively, so as to detect the state of the molecular photoforce system under different time delays, and then explore the dynamic process of the molecular photoforce system and the Raman scattering population lifetime of the system, and deeply understand the nonlinear up-conversion mechanism of the molecular photoforce system, providing a theoretical basis for significantly 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 resonance 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 nonlinear coefficient of the Rydberg exciton state 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 generated by 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 photodynamic transient dynamics detection system provided by the present invention adopts a high-peak power pulsed laser as the light source, replacing the current continuous light irradiation scheme. The advantage is that it uses picosecond or even femtosecond pulsed light irradiation, which can study the nonlinear scattering phenomenon of the molecular photodynamic system under high peak power without burning the sample. This method further deepens the understanding of the new nonlinear mechanisms and mechanisms of the molecular photodynamic system.

[0045] 2. The molecular photodynamic 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 photodynamic system in sequence is controlled. The state of the molecular photodynamic system under different time delays can be detected, and then the dynamic process of the molecular photodynamic system and the Raman scattering population lifetime of the system can be explored, and the nonlinear upconversion mechanism of the molecular photodynamic system can be deeply understood, providing a theoretical basis for significantly improving the mid-infrared upconversion efficiency.

[0046] 3. The molecular photodynamic transient dynamics detection system provided by the present invention uses a molecular photodynamic system to perform mid-infrared upconversion on the sample being tested, avoiding the drawbacks of conventional mid-infrared upconversion detectors, which require momentum matching conditions for combining infrared and visible light, and involve complex and difficult optical path and material design. The molecular photodynamic system of the present application for mid-infrared upconversion offers advantages such as system simplicity, high sensitivity, fast response, strong anti-interference capabilities, and low cost.

[0047] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make many possible changes and modifications to the technical solution of the present invention using the above technical content, or modify it into an equivalent embodiment with 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 shall fall within the scope of protection 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 assembly (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 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 retarder (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 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 measured (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 to 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 corresponding frequency that matches the specific infrared absorption mode of the molecular optical force 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 a composite 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 sphere.

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 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.

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 pumping light and the detection light reaching the sample by adjusting the optical path of the pulsed laser focused by the second lens (5).

Images