Monomolecular photoelectric signal monitoring method and device based on lens group test rod

Abstract

The invention relates to the technical field of signal testing, in particular to a monomolecular photoelectric signal monitoring method and device based on a lens group test rod, and the method comprises the following steps: laser passes through an optical parameter amplifier, an optical attenuation piece and an optical power detector, and then enters a climbing unit in the form of circular polarization exciting light or linear polarization exciting light; the light is reflected to a lens group test rod mounted in a test cavity of the comprehensive physical property measurement system; then the light is focused on the monomolecular device through the lens group; the lens group of the lens group test rod is adjusted to carry out multi-dimensional regulation and control on the monomolecular device, the probe of the comprehensive physical property measurement system monitors the conductivity of the monomolecular device, and the optical signal detection amplification unit and the computer cooperatively process the optical signal. According to the method and the device provided by the invention, monitoring of multi-dimensional single-molecule photoelectric signals of single-molecule photoelectric combination, single-molecule fluorescence and single-molecule spinning control can be realized at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of signal testing, and in particular to a single-molecule photoelectric signal monitoring method and device based on a lens group testing rod. Background Art

[0002] Femtosecond laser technology plays an important role in many fields such as biomedicine, optoelectronics and information industry. With the advancement of science and technology, the demand for high-performance femtosecond lasers continues to grow. High-repetition-rate femtosecond lasers are gradually used in molecular electronics due to their advantages such as higher time resolution, stable pulses and strong energy. They can provide single-molecule excited state characteristics on the picosecond time scale as well as the detection of chemical reactions, charge transfer and energy transfer dynamics.

[0003] The comprehensive physical property measurement system (PPMS for short) is a measurement platform that integrates various physical property measurement methods such as fully automatic magnetism, electricity, thermal and even morphology observation. It can provide extremely low temperatures of 50 millikelvin and strong magnetic fields of 9 Tesla by equipping different refrigerators. It has a built-in high vacuum system and magnetic shielding system. The test chamber can achieve vacuum conditions in a short time, and the escape magnetic field of the strong magnet is less than 5 Gauss at the edge of the host shell. Based on the high vacuum conditions, ultra-low temperatures and strong magnetic fields that PPMS can apply, and small optoelectronic devices can be physically connected to the test sample rod of PPMS, it has gradually become an ideal test platform for small optoelectronic devices, especially for the study of quantum behaviors such as quantum Hall effect and Coulomb blockade effect.

[0004] Recently, nanotechnology has developed rapidly, and device miniaturization has gradually become a research trend due to its advantages such as reduced losses and low costs. Currently, mainstream single-molecule devices often use single-layer graphene as source-drain electrodes to bridge molecules. Based on the advantages of graphene's ultra-thinness and good conductivity, graphene single-molecule devices have extremely high sensitivity. By applying source-drain bias or gate voltage, the relative energy level position of graphene and molecules can be regulated, and the photoelectric response of molecular properties can be tested. At present, the conductivity test of single-molecule devices under room temperature and low-temperature vacuum conditions has been relatively mature, but the time resolution of light excitation detection under vacuum conditions is still very low, and the dynamic process at the single-molecule level is also difficult to visualize. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a single-molecule photoelectric signal monitoring method and device based on a lens group test rod, which can simultaneously realize the monitoring of multi-dimensional single-molecule photoelectric signals of single-molecule photoelectric combination, single-molecule fluorescence and single-molecule spin manipulation.

[0006] The present invention is achieved through the following technical solutions: A single molecule photoelectric signal monitoring method based on a lens group test rod comprises the following steps: S1: The laser emitted from the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and then enters the climbing unit in the form of circularly polarized excitation light or linearly polarized excitation light; S2: The circularly polarized excitation light or the linearly polarized excitation light is reflected by the climbing unit to the lens group test rod installed in the test cavity of the comprehensive physical property measurement system; S3: The circularly polarized excitation light or the linearly polarized excitation light is focused onto the single-molecule device through the lens group of the lens group test rod; S4: Adjust the lens group of the lens group test rod to perform multi-dimensional control of the single-molecule device. After the probe of the integrated physical property measurement system monitors the conductivity of the single-molecule device, the optical signal detection and amplification unit and the computer work together to process the optical signal.

[0007] Furthermore, the lens group test rod comprises a rod body, a lens group and a sample stage, wherein the lens group comprises a first reflector, a dichroic filter, a first aperture diaphragm, a second aperture diaphragm, a 50-50 beam splitter and an objective lens, wherein the first reflector is rotatably mounted on the rod body and is aligned with the horizontal direction. The dual-color filter is rotatably mounted on the rod and is located below the first reflector, and is negatively oriented to the horizontal direction. The first pinhole diaphragm and the second pinhole diaphragm are fixedly mounted on the rod body and are located below the dichroic filter, and the first pinhole diaphragm and the second pinhole diaphragm are concentrically arranged, the 55 beam splitter is rotatably mounted on the rod body and is located between the first pinhole diaphragm and the second pinhole diaphragm, the objective lens is fixedly mounted on the rod body and is located below the second pinhole diaphragm, and the sample carrier is fixedly mounted on the rod body and is located below the objective lens.

[0008] Furthermore, multi-dimensional regulation includes single-molecule photoelectric coupling regulation, single-molecule fluorescence visualization, single-molecule fluorescence lifetime analysis and single-molecule spin regulation.

[0009] Further, the method of single-molecule photoelectric coupling regulation is as follows: S411: The first reflector and the 55 beam splitter are rotated out of the optical path. The laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence. The linearly polarized excitation light formed passes through the climbing unit and is incident on the two-color filter of the lens group test rod and then reflected. After passing through the first small aperture diaphragm and the second small aperture diaphragm, it is focused by the objective lens and irradiated on the single-molecule device with light response characteristics placed on the sample stage; S412: The probe of the integrated physical property measurement system monitors the conductivity of single-molecule devices with photoresponsive characteristics.

[0010] Furthermore, a camera and an LED white light source are installed on the top of the lens group test rod.

[0011] Further, the method of single-molecule fluorescence visualization is as follows: S421: Turn on the LED white light source, rotate the first reflector out of the light path, and rotate the 50-50 beam splitter and the dichroic filter into the light path; S422: Observe the surface of the single-molecule device with fluorescence function through a camera, and adjust the knob of the climbing unit so that the laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and the linearly polarized excitation light formed is incident on the two-color filter of the lens group test rod after passing through the climbing unit, and then reflected through the first small hole aperture, the 55 beam splitter, and the second small hole aperture, and then focused by the objective lens to irradiate the single-molecule device with fluorescence function; at the same time, white light passes through the two-color filter of the lens group test rod in sequence from above, transmits through the first small hole aperture, the 55 beam splitter, and the second small hole aperture, and then is focused by the objective lens to irradiate the single-molecule device with fluorescence function; S423: Move the 50-50 beam splitter out of the light path and turn off the LED white light source; S424: The single-molecule device with fluorescence function emits fluorescence. The fluorescence and linearly polarized excitation light are collected again by the objective lens and transmitted upward. The linearly polarized excitation light is filtered at the position of the two-color filter. The fluorescence passes through the two-color filter and enters the camera to realize the single-molecule excited state fluorescence visualization.

[0012] Optimally, the optical signal detection and amplification unit includes a monochromator, a photomultiplier tube, a single photon counter and a phase-locked amplifier connected in sequence.

[0013] Further, the method of single-molecule fluorescence lifetime analysis is as follows: S431: Turn on the LED white light source, rotate the first reflector out of the light path, and rotate the 50-50 beam splitter and the dichroic filter into the light path; S432: Observe the surface of the single-molecule device with fluorescence function through a camera, adjust the knob of the climbing unit, so that the laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and the linearly polarized excitation light formed is incident on the two-color filter of the lens group test rod after passing through the climbing unit, and then reflected by the first small hole aperture, the 55 beam splitter, and the second small hole aperture, and then focused by the objective lens to irradiate the single-molecule device with fluorescence function; at the same time, white light passes through the two-color filter of the lens group test rod from above in sequence, transmits through the first small hole aperture, the 55 beam splitter, and the second small hole aperture, and then is focused by the objective lens to irradiate the single-molecule device with fluorescence function; S433: Move the 50-50 beam splitter out of the light path, move the first reflector into the light path, turn off the LED white light source, the single-molecule device with fluorescence function emits fluorescence, the fluorescence and the linearly polarized excitation light are recollected by the objective lens and transmitted upward, the linearly polarized excitation light is filtered at the position of the dichroic filter, and the fluorescence passes through the dichroic filter and is reflected by the first reflector out of the lens group test rod; S434: The fluorescence reflected from the test rod of the lens group is collected by the optical fiber and then enters the monochromator. The signal from the monochromator is detected by the photomultiplier tube and then input into the single photon counter. The single photon counter transmits the number of collected photons to the computer through the phase-locked amplifier. The computer analyzes the fluorescence lifetime of the excited state through the fluorescence lifetime software.

[0014] Furthermore, the methods of single-molecule spin control include single-molecule spin initialization and electrical readout, single-molecule all-optical spin control and detection: Among them, the single-molecule spin initialization and electrical readout method are as follows: S441: The first reflector and the 55 beam splitter are rotated out of the optical path, and a quarter wave plate is set in front of the climbing unit. The laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and then passes through the quarter wave plate to form circularly polarized excitation light, and then passes through the climbing unit to enter the two-color filter of the lens group test rod, and then passes through the first small hole diaphragm and the second small hole diaphragm, and is focused by the objective lens and irradiated on the single molecule device placed on the sample stage; S442: The free radicals of the single-molecule device absorb photons, excite electrons to transition from low energy levels to high energy levels, and then return to the ground state through radiation transition. The electron spin is initialized and the initialization writing is completed by using the optical-magnetic combination; S443: The quarter wave plate rotates periodically to control the direction of the circularly polarized excitation light, and the spin is read out by the electrical Rabi measurement method; The single-molecule all-optical spin control and detection method is as follows: S451: Turn on the LED white light source, rotate the first reflector out of the light path, and rotate the 50-50 beam splitter and the dichroic filter into the light path; S452: Observe the surface of the single-molecule device having a fluorescent function and a diradical molecular functional side chain through a camera, and adjust the knob of the climbing unit so that the laser hits the single-molecule device having a fluorescent function and a diradical molecular functional side chain; S453: Move the 55 beam splitter out of the optical path, turn off the LED white light source, and set a 1 / 4 wave plate in front of the climbing unit, and rotate the 1 / 4 wave plate periodically. The laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and then passes through the 1 / 4 wave plate to form a circularly polarized excitation light. After passing through the climbing unit, the laser is incident on the two-color filter of the lens group test rod, and then reflects through the first small hole aperture and the second small hole aperture. It is focused by the objective lens and irradiated on the single-molecule device with fluorescence function and diradical molecular functional side chain; S454: moving the first reflector into the optical path, the single-molecule device having a fluorescence function and having a diradical molecular functional side chain emits fluorescence, the fluorescence and the circularly polarized excitation light are recollected by the objective lens and transmitted upward, the circularly polarized excitation light is filtered at the position of the dichromatic filter, and the fluorescence passes through the dichromatic filter and is reflected by the first reflector out of the lens group test rod; S455: The fluorescence reflected from the test rod of the lens group is collected by the optical fiber and then enters the monochromator. The signal from the monochromator is detected by the photomultiplier tube and then input into the single photon counter. The single photon counter transmits the collected photons to the computer through the phase-locked amplifier. The computer analyzes the fluorescence lifetime of the excited state through the fluorescence lifetime software to complete the single-molecule all-optical spin regulation and detection.

[0015] A single-molecule photoelectric signal monitoring device based on a lens group test rod, used to perform a single-molecule photoelectric signal monitoring method based on a lens group test rod as described in any one of the above, comprising a femtosecond laser, an optical parametric amplifier, an optical attenuation plate, an optical power detector, a quarter wave plate, a climbing unit, a comprehensive physical property measurement system connected to a camera and an LED white light source, a lens group test rod, an optical signal detection and amplification unit, and a computer, wherein the femtosecond laser, the optical parametric amplifier, the optical attenuation plate, and the optical power detector are coupled in sequence, the quarter wave plate is detachably and rotatably installed between the climbing unit and the optical power detector, the lens group test rod is placed in a test cavity of the comprehensive physical property measurement system, the lens group test rod comprises a rod body, a lens group, and a sample stage, the lens group comprises a first reflector, a dichroic filter, a first pinhole diaphragm, a second pinhole diaphragm, a 55 beam splitter, and an objective lens, the first reflector is rotatably installed on the rod body and is positive to the horizontal direction. The dual-color filter is rotatably mounted on the rod and is located below the first reflector, and is negatively oriented to the horizontal direction. The first and second pinhole apertures are fixedly mounted on the rod body and are located below the dichroic filter, and the first and second pinhole apertures are concentrically arranged. The 55 beam splitter is rotatably mounted on the rod body and is located between the first and second pinhole apertures. The objective lens is fixedly mounted on the rod body and is located below the second pinhole aperture. The sample stage is fixedly mounted on the rod body and is located below the objective lens. The single-molecule device to be detected is fixedly placed on the sample stage. The optical signal detection and amplification unit includes a monochromator, a photomultiplier tube, a single-photon counter and a phase-locked amplifier connected in sequence. The monochromator is coupled to the first reflector through an optical fiber, and the phase-locked amplifier is connected to a computer. The climbing unit includes a second reflector and a third reflector.

[0016] Beneficial effects of the invention: The present invention provides a single-molecule photoelectric signal monitoring method and device based on a lens group test rod, which has the following advantages: 1. The present invention combines the femtosecond laser with the comprehensive physical property measurement system through a lens group test rod, which ensures direct excitation of the laser pulse, does not have additional pulse broadening, has higher time resolution, and can achieve picosecond level measurement; 2. The present invention can realize photoelectric combination, which can not only complete the ultra-low temperature and strong magnetic field test based on the comprehensive physical property measurement system, but also realize the optical excitation function; 3. The present invention can realize fluorescence imaging of micro-nano structures or materials and measurement of fluorescence lifetime spectra at the picosecond level, and can flexibly change the test environment and magnetic field to observe the dynamic process under different conditions; 4. The present invention has the potential to be applied to quantum bit spin manipulation, which is a cutting-edge science of spin manipulation. In addition to the manipulation of circularly polarized light, it can also realize the spin reading of circularly polarized light under electroluminescence. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the process of the present invention.

[0018] Figure 2 It is a schematic diagram of the device of the present invention.

[0019] Figure 3 It is a schematic diagram of the structure of the graphene-based diarylethene single-molecule device of the present invention.

[0020] Figure 4 1 is the current-voltage characteristic curve of the single-molecule device of the present invention before and after being excited by 600-nanometer light.

[0021] Figure 5 It is the fluorescence lifetime diagram of the single-molecule device of the present invention.

[0022] Figure 6It is a schematic diagram of the test results of the lens assembly of the present invention.

[0023] In the figure: 1. Femtosecond laser; 2. Optical parametric amplifier; 3. Integrated physical property measurement system connected with camera and LED white light source; 4. Climbing unit; 4-1. Second reflector; 4-2. Third reflector; 5. Optical signal detection and amplification unit; 5-1. Monochromator; 5-2. Photomultiplier tube; 5-3. Single photon counter; 5-4. Phase-locked amplifier; 6. Computer; 7. Light attenuator; 8. Optical power detector; 9. 1 / 4 wave plate; 10. Lens group test rod; 10-1. Rod body; 10-2. Sample carrier; 10-3. First reflector; 10-4. Two-color filter; 10-5. First pinhole aperture; 10-6. Second pinhole aperture; 10-7. 55 beam splitter; 10-8. Objective lens; 11. Graphene electrode source end; 12. Graphene electrode drain end; 13. Single diarylethene molecule; 14. Silicon wafer. DETAILED DESCRIPTION

[0024] A method for monitoring single-molecule photoelectric signals based on a lens group test rod comprises the following steps, and its flow chart is as follows: Figure 1 As shown: S1: The laser emitted from the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and then enters the climbing unit in the form of circularly polarized excitation light or linearly polarized excitation light; The climbing unit here can be composed of two mirrors, namely the second reflector and the third reflector, and both are high-reflectivity aluminum mirrors, so as to directly introduce the femtosecond laser into the optical entrance of the lens group test rod, ensuring direct excitation of the laser pulse without additional pulse broadening, so that it has higher time resolution and can achieve picosecond level measurement.

[0025] The output optical power of the laser works together with the optical attenuation plate and is detected by an optical power detector to ensure that the optical power is within a range that will not damage the single-molecule device.

[0026] S2: The circularly polarized excitation light or the linearly polarized excitation light is reflected by the climbing unit to the lens group test rod installed in the test cavity of the comprehensive physical property measurement system; The comprehensive physical property measurement system is a measurement platform that integrates various physical property measurement methods such as fully automatic magnetism, electricity, thermal and even morphology observation. By equipping different refrigerators, it can provide an extremely low temperature as low as 50 millikelvin; at the same time, it can provide a strong magnetic field of 9 Tesla, with a built-in high vacuum system and magnetic shielding system. The sample chamber can achieve vacuum conditions in a short time, and the escape magnetic field of the strong magnet is less than 5 Gauss at the edge of the host casing.

[0027] The tests involved in the present invention are all carried out under vacuum conditions, with a pressure less than Pa, the test instrument is an integrated physical property measurement system. The pulse tube refrigerator provided by the integrated physical property measurement system realizes the temperature rise and fall control of the sample. The magnetic field control is completed by the conduction cooling superconducting magnet provided by the integrated physical property measurement system. The optical excitation can be completed by a titanium-doped sapphire femtosecond laser. The optical parametric amplifier can adopt a narrow pulse width femtosecond optical parametric amplifier, which can realize broadband optical excitation in the wavelength range of 325 nanometers to 2500 nanometers. The laser pulse width is adjustable from hundreds of femtoseconds to sub-picoseconds, with a time resolution of picoseconds.

[0028] Specifically, the lens group test rod includes a rod body, a lens group and a sample stage, the lens group includes a first reflector, a dichroic filter, a first aperture diaphragm, a second aperture diaphragm, a 55 beam splitter and an objective lens, the first reflector is rotatably mounted on the rod body and is aligned with the horizontal direction. The two-color filter is rotatably mounted on the rod and is located below the first reflector, and is negatively correlated with the horizontal direction. The first pinhole diaphragm and the second pinhole diaphragm are fixedly mounted on the rod body and are located below the dichroic filter, and the first pinhole diaphragm and the second pinhole diaphragm are concentrically arranged, the 55 beam splitter is rotatably mounted on the rod body and is located between the first pinhole diaphragm and the second pinhole diaphragm, the objective lens is fixedly mounted on the rod body and is located below the second pinhole diaphragm, and the sample carrier is fixedly mounted on the rod body and is located below the objective lens.

[0029] S3: The circularly polarized excitation light or the linearly polarized excitation light is focused onto the single-molecule device through the lens group of the lens group test rod; S4: Adjust the lens group of the lens group test rod to perform multi-dimensional control of the single-molecule device. After the probe of the integrated physical property measurement system monitors the conductivity of the single-molecule device, the optical signal detection and amplification unit and the computer work together to process the optical signal.

[0030] Specifically, multi-dimensional regulation includes single-molecule photoelectric coupling regulation, single-molecule fluorescence visualization, single-molecule fluorescence lifetime analysis and single-molecule spin regulation.

[0031] Further, the method of single-molecule photoelectric coupling regulation is as follows: S411: The first reflector and the 55 beam splitter are rotated out of the optical path. The laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence. The linearly polarized excitation light formed passes through the climbing unit and is incident on the two-color filter of the lens group test rod and then reflected. After passing through the first small aperture diaphragm and the second small aperture diaphragm, it is focused by the objective lens and irradiated on the single-molecule device with light response characteristics placed on the sample stage; S412: The probe of the integrated physical property measurement system monitors the conductivity of the single-molecule device with light response characteristics, and transmits it to the computer for display after amplification by the optical signal detection and amplification unit.

[0032] For single-molecule photoelectric coupling regulation, a graphene-based diarylethene single-molecule device can be used, and its structural schematic diagram is shown in the figure. Figure 3 As shown in the figure, 11 is the graphene electrode source terminal, 12 is the graphene electrode drain terminal, 13 is a single diarylethene molecule, and 14 is a silicon wafer; the graphene electrode source terminal and the graphene electrode drain terminal are both located above the silicon wafer, and the two ends of the single diarylethene molecule are covalently connected to the graphene electrode source terminal and the graphene electrode drain terminal, respectively.

[0033] Since diarylethene molecules undergo a ring-closure reaction under ultraviolet light excitation and a ring-opening reaction under visible light irradiation, the open and closed states correspond to low and high conductance, respectively. Based on the temperature control system of the integrated physical property measurement system, the test can be performed in the temperature range of 2 Kelvin to 300 Kelvin. At a temperature of 180 Kelvin, a source-drain voltage ranging from -1 V to 1 V with an interval of 5 mV was applied, and the current-voltage characteristic curves of the single-molecule device before and after 600 nm light excitation were measured as follows: Figure 4 shown.

[0034] from Figure 4 It can be seen that photoexcitation as a variable leads to a significant decrease in the current-voltage characteristic curve after excitation, proving that the diarylethene molecules in the graphene-based diarylethene single-molecule device undergo a ring-opening reaction.

[0035] In addition, the ring-opening and ring-closing reactions of diarylethene molecules can be monitored by conductivity by switching the wavelength of the excitation light, and reversible molecular switches can be achieved through repeated visible light or ultraviolet light excitation. Magnetic fields and temperature control can also be flexibly applied to explore the photoreaction rate at different temperatures, and the selectivity of the ring-opening and ring-closing reactions for the optimal wavelength can be enhanced by applying a magnetic field.

[0036] Furthermore, a camera and an LED white light source are installed on the top of the lens group test rod.

[0037] Further, the method of single-molecule fluorescence visualization is as follows: S421: Turn on the LED white light source, rotate the first reflector out of the light path, and rotate the 50-50 beam splitter and the dichroic filter into the light path; S422: Observe the surface of the single-molecule device with fluorescence function through a camera, adjust the knob of the climbing unit, so that the laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and the linearly polarized excitation light formed is incident on the two-color filter of the lens group test rod after passing through the climbing unit, and then reflected through the first small hole aperture, the 55 beam splitter, and the second small hole aperture, and then focused by the objective lens to irradiate the single-molecule device with fluorescence function; at the same time, white light passes through the two-color filter of the lens group test rod in sequence from above, transmits through the first small hole aperture, the 55 beam splitter, and the second small hole aperture, and then is focused by the objective lens to irradiate the single-molecule device with fluorescence function, which can play a lighting role, facilitate observation through the camera, and ensure that the laser irradiates the surface of the single-molecule device with fluorescence function; S423: Move the 50-50 beam splitter out of the light path and turn off the LED white light source; S424: The single-molecule device with fluorescence function emits fluorescence. The fluorescence and linearly polarized excitation light are collected again by the objective lens and transmitted upward. The linearly polarized excitation light is filtered at the position of the two-color filter. The fluorescence passes through the two-color filter and enters the camera to realize the single-molecule excited state fluorescence visualization.

[0038] Specifically, the method of single-molecule fluorescence regulation can use a perylene diimide (PDI) single-molecule device. Among them, the PDI molecule has significant luminescence characteristics and can emit stable long-wavelength fluorescence after short-wavelength excitation. A laser with a wavelength of 400 nanometers is used for excitation, and a 425-nanometer two-color filter can be used to ensure that the excitation light is completely filtered and the fluorescence passes. Then, by calibrating the light path, the laser can be accurately incident on the single-molecule device, the molecule is excited to transition to the excited state, and the self-excited state decays back to the ground state to emit fluorescence. Under the action of the two-color filter, the excitation light is filtered out, and only the fluorescence of the sample can enter the camera and be observed. This method can achieve fluorescence imaging of micro-nano structures or materials less than 50 nanometers.

[0039] Optimally, the optical signal detection and amplification unit includes a monochromator, a photomultiplier tube, a single photon counter and a phase-locked amplifier connected in sequence.

[0040] Further, the method of single-molecule fluorescence lifetime analysis is as follows: S431: Turn on the LED white light source, rotate the first reflector out of the light path, and rotate the 50-50 beam splitter and the dichroic filter into the light path; S432: Observe the surface of the single-molecule device with fluorescence function through a camera, adjust the knob of the climbing unit, so that the laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and the linearly polarized excitation light formed is incident on the two-color filter of the lens group test rod after passing through the climbing unit, and then reflected by the first small hole aperture, the 55 beam splitter, and the second small hole aperture, and then focused by the objective lens to irradiate the single-molecule device with fluorescence function; at the same time, white light passes through the two-color filter of the lens group test rod from above in sequence, transmits through the first small hole aperture, the 55 beam splitter, and the second small hole aperture, and then is focused by the objective lens to irradiate the single-molecule device with fluorescence function; S433: Move the 50-50 beam splitter out of the light path, move the first reflector into the light path, turn off the LED white light source, the single-molecule device with fluorescence function emits fluorescence, the fluorescence and the linearly polarized excitation light are recollected by the objective lens and transmitted upward, the linearly polarized excitation light is filtered at the position of the dichroic filter, and the fluorescence passes through the dichroic filter and is reflected by the first reflector out of the lens group test rod; S434: The fluorescence reflected from the test rod of the lens group is collected by the optical fiber and then enters the monochromator. The signal from the monochromator is detected by the photomultiplier tube and then input into the single photon counter. The single photon counter transmits the number of collected photons to the computer through the phase-locked amplifier. The computer analyzes the fluorescence lifetime of the excited state through the fluorescence lifetime software.

[0041] The signal from the monochromator is detected by a photomultiplier tube and then input into a single-photon counter. The single-photon counter has a time resolution of picoseconds. After collecting a large number of photons, the relationship between the time delay and the number of collected photons can be statistically calculated, thereby reflecting the fluorescence lifetime of the excited state. It can be used to study molecular conformational changes, intramolecular or intermolecular proton transfer and other processes.

[0042] This fluorescence lifetime is the result of a large number of photon collection statistics. When a short laser pulse is excited, after a time delay , the sample emits fluorescence. The high repetition rate laser will continuously excite the sample within a certain period of time. The electrical signal of each excitation and the electrical signal emitted by the photomultiplier tube each time it detects a photon are input into the single photon counter. Since the laser pulse width is constant, the time of collecting photons is different. The fluorescence lifetime is obtained by classification and statistics based on the collection time.

[0043] The single-molecule fluorescence lifetime analysis method can also use a 400-nanometer laser for excitation, equipped with a 425-nanometer dual-color filter, which can ensure that the excitation light is completely filtered and the fluorescence passes. The single-molecule device can be a perylene diimide (PDI) single-molecule device, and the fluorescence lifetime spectrum obtained by collecting the excited fluorescence photons is as follows: Figure 5 shown.

[0044] Furthermore, the methods of single-molecule spin control include single-molecule spin initialization and electrical readout, single-molecule all-optical spin control and detection: Among them, the single-molecule spin initialization and electrical readout method are as follows: S441: The first reflector and the 55 beam splitter are rotated out of the optical path, and a quarter wave plate is set in front of the climbing unit. The laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and then passes through the quarter wave plate to form circularly polarized excitation light, and then passes through the climbing unit to enter the two-color filter of the lens group test rod, and then passes through the first small hole diaphragm and the second small hole diaphragm, and is focused by the objective lens and irradiated on the single molecule device placed on the sample stage; S442: The free radicals of the single-molecule device absorb photons, excite electrons to transition from low energy levels to high energy levels, and then return to the ground state through radiation transition. The electron spin is initialized and the initialization writing is completed by using the optical-magnetic combination; S443: The quarter wave plate rotates periodically to control the direction of the circularly polarized excitation light, and the spin is read out by the electrical Rabi measurement method; Specifically, single-molecule spin initialization and electrical readout can use graphene single-molecule devices with single free radical functional side chains. Free radical molecules usually have unpaired electrons in the outer layer, which makes their electronic structure highly reactive and energetic. When a free radical absorbs a photon, it excites the electron to transition from a low energy level to a high energy level, and then returns to the ground state through a radiative transition. As a natural two-level system, free radical molecules are easy to manipulate, so the ground state and excited state can be used as a two-level system, and the spin of its electron can be initialized using optical-magnetic coupling, and the spin can be read out through electrical Rabi measurement.

[0045] In the conductivity test of single-molecule devices, the conductivity state of the device will change due to the influence of the external environment such as temperature and gate voltage, and the intramolecular effects such as stereoelectronic effects and molecular conformation changes. Based on this, it is necessary to first find the optimal temperature and gate voltage configuration in the absence of a magnetic field, and then apply a 0.1 Tesla magnetic field to the single free radical group at the optimal temperature based on the comprehensive physical property measurement system PPMS that can achieve temperature control and magnetic control, so that the degenerate energy levels with ground state and excited state spin magnetic quantum numbers of ±1 / 2 undergo Zeeman splitting.

[0046] Then, left-handed circularly polarized light can be applied to irradiate the free radical molecules, so that the electrons with upward spin direction are excited to the excited state and spin flip. When the electrons fall back to the ground state, the single free radical electron spin polarization is achieved, completing the initialization writing of the quantum bit state.

[0047] The spin can be read out by the electrical Rabi measurement method, and the time of magnetic field evolution can be calculated based on the formula of Zeeman splitting. After the phase changes for the required time, the left-handed circularly polarized light is converted into right-handed circularly polarized light. Here, an electric motor can be used to periodically rotate the 1 / 4 wave plate to control the direction of the circularly polarized light.

[0048] According to the Zeeman effect, when a magnetic field strength is applied The energy change of spin level splitting is Is the following formula: ; in, It is the electronic Rand factor, It is the Bohr magneton.

[0049] Furthermore, the Rabi oscillation frequency is proportional to the energy change of the spin level splitting, that is, ; in: is the Rabi oscillation frequency, represents Planck's constant.

[0050] This can be obtained through The time required for the phase is .

[0051] Then, right-handed circularly polarized light is irradiated onto the free radical molecule, so that the spin magnetic quantum number is The ground state electrons transition to the excited state energy level, completing the spin readout of the quantum bit state.

[0052] While left- and right-handed circularly polarized light is regulating free radical molecules, the Rabi oscillation spectrum of conductivity between the ground state and the excited state can be obtained through Rabi measurement of conductivity, thereby calculating the relaxation time and decoherence time of the spin quantum state.

[0053] The single-molecule all-optical spin control and detection method is as follows: S451: Turn on the LED white light source, rotate the first reflector out of the light path, and rotate the 50-50 beam splitter and the dichroic filter into the light path; S452: Observe the surface of the single-molecule device having a fluorescent function and a diradical molecular functional side chain through a camera, and adjust the knob of the climbing unit so that the laser hits the single-molecule device having a fluorescent function and a diradical molecular functional side chain; S453: Move the 55 beam splitter out of the optical path, turn off the LED white light source, and set a 1 / 4 wave plate in front of the climbing unit, and rotate the 1 / 4 wave plate periodically. The laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and then passes through the 1 / 4 wave plate to form a circularly polarized excitation light. After passing through the climbing unit, the laser is incident on the two-color filter of the lens group test rod, and then reflects through the first small hole aperture and the second small hole aperture. It is focused by the objective lens and irradiated on the single-molecule device with fluorescence function and diradical molecular functional side chain; S454: moving the first reflector into the optical path, the single-molecule device having a fluorescence function and having a diradical molecular functional side chain emits fluorescence, the fluorescence and the circularly polarized excitation light are recollected by the objective lens and transmitted upward, the circularly polarized excitation light is filtered at the position of the dichromatic filter, and the fluorescence passes through the dichromatic filter and is reflected by the first reflector out of the lens group test rod; S455: The fluorescence reflected from the test rod of the lens group is collected by the optical fiber and then enters the monochromator. The signal from the monochromator is detected by the photomultiplier tube and then input into the single photon counter. The single photon counter transmits the collected photons to the computer through the phase-locked amplifier. The computer analyzes the fluorescence lifetime of the excited state through the fluorescence lifetime software to complete the single-molecule all-optical spin regulation and detection.

[0054] Single-molecule all-optical spin control and detection methods can use single-molecule devices with functional side chains of diradical molecules. The diradical component has a specific three-level ground state with spin multiplicities of ±1 and 0, among which the ground state with a spin magnetic quantum number of ±1 has a higher energy level.

[0055] The optimal temperature and gate voltage configuration can be found in the absence of a magnetic field. Based on the comprehensive physical property measurement system PPMS that can achieve temperature control and magnetic control, a 0.1 Tesla magnetic field is applied to the diradical group at the optimal temperature to cause Zeeman splitting of the degenerate energy levels with ground and excited state spin magnetic quantum numbers of ±1.

[0056] When left-handed circularly polarized light is applied for excitation, the electrons with spin direction upward are excited to the excited state with spin magnetic quantum number of −1 and undergo spin flip, falling back to the ground state with spin magnetic quantum number of −1 and emitting fluorescence. At this time, the electron spin direction is downward, completing spin polarization.

[0057] Based on the formula of Zeeman effect, after After the time required for the phase shift, the left-handed circularly polarized light is converted into right-handed circularly polarized light. Here, an electric motor can be used to periodically rotate the 1 / 4 wave plate, so that the polarization direction of the excitation light changes periodically between left-handed polarized light and right-handed polarized light, and further, the electron spin is flipped.

[0058] At this time, the fluorescence photons are collected by using a single photon counter, and the fluorescence lifetime signal is collected to carry out Rabi measurement. If the collected fluorescence lifetime is short, it means that the electron is in the spin singlet state, otherwise it is in the spin triplet state. Based on the Rabi oscillation spectrum of the fluorescence lifetime, the relaxation time and decoherence time of the spin quantum state can be calculated.

[0059] The single-molecule all-optical spin regulation and detection method provided by the present invention maintains the pulse width of the laser pulse by using a self-designed lens group test rod, and can achieve femtosecond level excitation; further, through the high time-resolved time-correlated single-photon counting function, it can achieve picosecond level resolution fluorescence lifetime measurement, which is basically consistent with the time magnitude of the spin flip time, and can realize the control and readout of electron spin flip.

[0060] A single-molecule photoelectric signal monitoring device based on a lens group test rod is used to perform any of the single-molecule photoelectric signal monitoring methods based on a lens group test rod described above. The schematic diagram of the device structure is shown in FIG. Figure 2 As shown, it includes a femtosecond laser 1, an optical parametric amplifier 2, an optical attenuation plate 7, an optical power detector 8, a quarter wave plate 9, a climbing unit 4, a comprehensive physical property measurement system 3 connected to a camera and an LED white light source, a lens group test rod 10, an optical signal detection and amplification unit 5 and a computer 6. The femtosecond laser, the optical parametric amplifier, the optical attenuation plate, and the optical power detector are coupled in sequence, the quarter wave plate is detachably and rotatably installed between the climbing unit and the optical power detector, the lens group test rod is placed in the test cavity of the comprehensive physical property measurement system and coupled to the climbing unit, and the result schematic diagram of the lens group test rod is shown in FIG. Figure 6 As shown, it includes a rod body 10-1, a lens group and a sample stage 10-2, the lens group includes a first reflector 10-3, a two-color filter 10-4, a first pinhole diaphragm 10-5, a second pinhole diaphragm 10-6, a 55 beam splitter 10-7 and an objective lens 10-8, the first reflector is rotatably mounted on the rod body and is aligned with the horizontal direction The two-color filter is rotatably mounted on the rod and is located below the first reflector, and is negatively correlated with the horizontal direction. Angle, the first pinhole aperture and the second pinhole aperture are fixedly mounted on the rod body and are located below the two-color filter, and the first pinhole aperture and the second pinhole aperture are concentrically arranged, the 55 beam splitter is rotatably mounted on the rod body and is located between the first pinhole aperture and the second pinhole aperture, the objective lens is fixedly mounted on the rod body and is located below the second pinhole aperture, the sample stage is fixedly mounted on the rod body and is located below the objective lens, the single-molecule device to be detected is fixedly placed on the sample stage, the optical signal detection and amplification unit includes a monochromator 5-1, a photomultiplier tube 5-2, a single-photon counter 5-3 and a phase-locked amplifier 5-4 connected in sequence, the monochromator is coupled to the first reflector through an optical fiber, the phase-locked amplifier is connected to a computer, and the climbing unit includes a second reflector 4-1 and a third reflector 4-2.

[0061] In summary, the present invention provides a single-molecule photoelectric signal monitoring method and device based on a lens group test rod. By using an independently designed lens group test rod, a femtosecond laser is linked with a comprehensive physical property measurement system, which can simultaneously realize the monitoring of multi-dimensional single-molecule photoelectric signals of single-molecule photoelectric coupling, single-molecule fluorescence and single-molecule spin manipulation.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for monitoring single-molecule photoelectric signals based on a lens group test rod, characterized in that: The steps include: S1: The laser emitted from the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and then enters the climbing unit in the form of circularly polarized excitation light or linearly polarized excitation light; S2: The circularly polarized excitation light or the linearly polarized excitation light is reflected by the climbing unit to the lens group test rod installed in the test cavity of the comprehensive physical property measurement system; S3: The circularly polarized excitation light or the linearly polarized excitation light is focused onto the single-molecule device through the lens group of the lens group test rod; S4: Adjust the lens group of the lens group test rod to perform multi-dimensional control of the single-molecule device. After the probe of the integrated physical property measurement system monitors the conductivity of the single-molecule device, the optical signal detection and amplification unit and the computer work together to process the optical signal.

2. A method for monitoring single-molecule photoelectric signals based on a lens group test rod according to claim 1, characterized in that: The lens group test rod comprises a rod body, a lens group and a sample stage, the lens group comprises a first reflector, a dichroic filter, a first aperture diaphragm, a second aperture diaphragm, a 55 beam splitter and an objective lens, the first reflector is rotatably mounted on the rod body and is aligned with the horizontal direction. The dual-color filter is rotatably mounted on the rod and is located below the first reflector, and is negatively oriented to the horizontal direction. The first pinhole diaphragm and the second pinhole diaphragm are fixedly mounted on the rod body and are located below the dichroic filter, and the first pinhole diaphragm and the second pinhole diaphragm are concentrically arranged, the 55 beam splitter is rotatably mounted on the rod body and is located between the first pinhole diaphragm and the second pinhole diaphragm, the objective lens is fixedly mounted on the rod body and is located below the second pinhole diaphragm, and the sample carrier is fixedly mounted on the rod body and is located below the objective lens.

3. A single molecule photoelectric signal monitoring method based on a lens group test rod according to claim 2, characterized in that: The multi-dimensional regulation includes single-molecule photoelectric coupling regulation, single-molecule fluorescence visualization, single-molecule fluorescence lifetime analysis and single-molecule spin regulation.

4. A method for monitoring single-molecule photoelectric signals based on a lens group test rod according to claim 3, characterized in that: The method of single-molecule photoelectric coupling regulation is as follows: S411: The first reflector and the 55 beam splitter are rotated out of the optical path. The laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence. The linearly polarized excitation light formed passes through the climbing unit and is incident on the two-color filter of the lens group test rod and then reflected. After passing through the first small aperture diaphragm and the second small aperture diaphragm, it is focused by the objective lens and irradiated on the single-molecule device with light response characteristics placed on the sample stage; S412: The probe of the integrated physical property measurement system monitors the conductivity of single-molecule devices with photoresponsive characteristics.

5. The method for monitoring single-molecule photoelectric signals based on a lens group test rod according to claim 3, characterized in that: A camera and an LED white light source are installed on the top of the lens group test rod.

6. A method for monitoring single-molecule photoelectric signals based on a lens group test rod according to claim 5, characterized in that: The method for single-molecule fluorescence visualization is as follows: S421: Turn on the LED white light source, rotate the first reflector out of the light path, and rotate the 50-50 beam splitter and the dichroic filter into the light path; S422: Observe the surface of the single-molecule device with fluorescence function through a camera, and adjust the knob of the climbing unit so that the laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and the linearly polarized excitation light formed is incident on the two-color filter of the lens group test rod after passing through the climbing unit, and then reflected through the first small hole aperture, the 55 beam splitter, and the second small hole aperture, and then focused by the objective lens to irradiate the single-molecule device with fluorescence function; at the same time, white light passes through the two-color filter of the lens group test rod in sequence from above, transmits through the first small hole aperture, the 55 beam splitter, and the second small hole aperture, and then is focused by the objective lens to irradiate the single-molecule device with fluorescence function; S423: Move the 50-50 beam splitter out of the light path and turn off the LED white light source; S424: The single-molecule device with fluorescence function emits fluorescence. The fluorescence and linearly polarized excitation light are collected again by the objective lens and transmitted upward. The linearly polarized excitation light is filtered at the position of the two-color filter. The fluorescence passes through the two-color filter and enters the camera to realize the single-molecule excited state fluorescence visualization.

7. The method for monitoring single-molecule photoelectric signals based on a lens group test rod according to claim 5, characterized in that: The optical signal detection and amplification unit comprises a monochromator, a photomultiplier tube, a single photon counter and a phase-locked amplifier which are connected in sequence.

8. The method for monitoring single-molecule photoelectric signals based on a lens group test rod according to claim 7, characterized in that: The method for single-molecule fluorescence lifetime analysis is as follows: S431: Turn on the LED white light source, rotate the first reflector out of the light path, and rotate the 50-50 beam splitter and the dichroic filter into the light path; S432: Observe the surface of the single-molecule device with fluorescence function through a camera, adjust the knob of the climbing unit, so that the laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and the linearly polarized excitation light formed is incident on the two-color filter of the lens group test rod after passing through the climbing unit, and then reflected by the first small hole aperture, the 55 beam splitter, and the second small hole aperture, and then focused by the objective lens to irradiate the single-molecule device with fluorescence function; at the same time, white light passes through the two-color filter of the lens group test rod from above in sequence, transmits through the first small hole aperture, the 55 beam splitter, and the second small hole aperture, and then is focused by the objective lens to irradiate the single-molecule device with fluorescence function; S433: Move the 50-50 beam splitter out of the light path, move the first reflector into the light path, turn off the LED white light source, the single-molecule device with fluorescence function emits fluorescence, the fluorescence and the linearly polarized excitation light are recollected by the objective lens and transmitted upward, the linearly polarized excitation light is filtered at the position of the dichroic filter, and the fluorescence passes through the dichroic filter and is reflected by the first reflector out of the lens group test rod; S434: The fluorescence reflected from the test rod of the lens group is collected by the optical fiber and then enters the monochromator. The signal from the monochromator is detected by the photomultiplier tube and then input into the single photon counter. The single photon counter transmits the number of collected photons to the computer through the phase-locked amplifier. The computer analyzes the fluorescence lifetime of the excited state through the fluorescence lifetime software.

9. The method for monitoring single-molecule photoelectric signals based on a lens group test rod according to claim 5, characterized in that: The methods of single-molecule spin control include single-molecule spin initialization and electrical readout, single-molecule all-optical spin control and detection: Among them, the single-molecule spin initialization and electrical readout method are as follows: S441: The first reflector and the 55 beam splitter are rotated out of the optical path, and a quarter wave plate is set in front of the climbing unit. The laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and then passes through the quarter wave plate to form circularly polarized excitation light, and then passes through the climbing unit to enter the two-color filter of the lens group test rod, and then passes through the first small hole diaphragm and the second small hole diaphragm, and is focused by the objective lens and irradiated on the single molecule device placed on the sample stage; S442: The free radicals of the single-molecule device absorb photons, excite electrons to transition from low energy levels to high energy levels, and then return to the ground state through radiation transition. The electron spin is initialized and the initialization writing is completed by using the optical-magnetic combination; S443: The quarter wave plate rotates periodically to control the direction of the circularly polarized excitation light, and the spin is read out by the electrical Rabi measurement method; The single-molecule all-optical spin control and detection method is as follows: S451: Turn on the LED white light source, rotate the first reflector out of the light path, and rotate the 50-50 beam splitter and the dichroic filter into the light path; S452: Observe the surface of the single-molecule device having a fluorescent function and a diradical molecular functional side chain through a camera, and adjust the knob of the climbing unit so that the laser hits the single-molecule device having a fluorescent function and a diradical molecular functional side chain; S453: Move the 55 beam splitter out of the optical path, turn off the LED white light source, and set a 1 / 4 wave plate in front of the climbing unit, and rotate the 1 / 4 wave plate periodically. The laser emitted by the femtosecond laser passes through the optical parametric amplifier, the optical attenuator, and the optical power detector in sequence, and then passes through the 1 / 4 wave plate to form a circularly polarized excitation light. After passing through the climbing unit, the laser is incident on the two-color filter of the lens group test rod, and then reflects through the first small hole aperture and the second small hole aperture. It is focused by the objective lens and irradiated on the single-molecule device with fluorescence function and diradical molecular functional side chain; S454: moving the first reflector into the optical path, the single-molecule device having a fluorescence function and having a diradical molecular functional side chain emits fluorescence, the fluorescence and the circularly polarized excitation light are recollected by the objective lens and transmitted upward, the circularly polarized excitation light is filtered at the position of the dichromatic filter, and the fluorescence passes through the dichromatic filter and is reflected by the first reflector out of the lens group test rod; S455: The fluorescence reflected from the test rod of the lens group is collected by the optical fiber and then enters the monochromator. The signal from the monochromator is detected by the photomultiplier tube and then input into the single photon counter. The single photon counter transmits the collected photons to the computer through the phase-locked amplifier. The computer analyzes the fluorescence lifetime of the excited state through the fluorescence lifetime software to complete the single-molecule all-optical spin regulation and detection.

10. A single-molecule photoelectric signal monitoring device based on a lens group test rod, used to perform a single-molecule photoelectric signal monitoring method based on a lens group test rod as claimed in any one of claims 1 to 9, characterized in that: The invention comprises a femtosecond laser, an optical parametric amplifier, an optical attenuation sheet, an optical power detector, a quarter wave plate, a climbing unit, a comprehensive physical property measurement system connected with a camera and an LED white light source, a lens group test rod, an optical signal detection and amplification unit, and a computer. The femtosecond laser, the optical parametric amplifier, the optical attenuation sheet, and the optical power detector are coupled in sequence. The quarter wave plate is detachably and rotatably installed between the climbing unit and the optical power detector. The lens group test rod is placed in a test cavity of the comprehensive physical property measurement system. The lens group test rod comprises a rod body, a lens group, and a sample carrier. The lens group comprises a first reflector, a two-color filter, a first pinhole diaphragm, a second pinhole diaphragm, a 55 beam splitter, and an objective lens. The first reflector is rotatably installed on the rod body and is positive to the horizontal direction. The dual-color filter is rotatably mounted on the rod and is located below the first reflector, and is negatively oriented to the horizontal direction. The first and second pinhole apertures are fixedly mounted on the rod body and are located below the dichroic filter, and the first and second pinhole apertures are concentrically arranged. The 55 beam splitter is rotatably mounted on the rod body and is located between the first and second pinhole apertures. The objective lens is fixedly mounted on the rod body and is located below the second pinhole aperture. The sample stage is fixedly mounted on the rod body and is located below the objective lens. The single-molecule device to be detected is fixedly placed on the sample stage. The optical signal detection and amplification unit includes a monochromator, a photomultiplier tube, a single-photon counter and a phase-locked amplifier connected in sequence. The monochromator is coupled to the first reflector through an optical fiber, and the phase-locked amplifier is connected to a computer. The climbing unit includes a second reflector and a third reflector.

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