Single-quantum-state molecular beam preparation system, device and method

Abstract

The invention discloses a single quantum state molecular beam preparation system, device and method.The system comprises a molecule excitation module and a laser output module, the molecule excitation module comprises a gas inlet pipeline and a molecular beam valve, and the gas inlet pipeline is used for injecting gas molecules to be excited into the molecular beam valve; the molecular beam valve is used for reducing gas molecules in various quantum states into ground states to obtain ground state molecular beams; the laser output module comprises a laser source assembly and a cylindrical convex lens, the laser source assembly is used for outputting continuous laser, the continuous laser passes through the cylindrical convex lens to obtain fan-shaped excitation laser, and the excitation laser is perpendicular to the flight direction of the ground-state molecular beam and intersects with the ground-state molecular beam. The photon energy and the molecular absorption energy level of the excitation laser intersect in time, the laser energy is not zero, the adiabatic excitation condition is met, and the excitation efficiency approaches 100%, so that adiabatic excitation is carried out by using the continuous laser, and efficient excitation is realized in a continuous spatial domain. The method is suitable for the technical field of molecular beam preparation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of molecular beam preparation, in particular to a single quantum state molecular beam preparation system, device and method. BACKGROUND

[0002] In many reaction systems, the quantum state structure of the reactant molecules, especially the vibrational excited state, has a key influence on the path selection, energy barrier crossing and product distribution of chemical reactions. Therefore, it is extremely important for molecular reaction dynamics research to prepare a specific quantum state molecular beam with high purity and controllable population.

[0003] At present, traditional thermal excitation, discharge excitation and other methods cannot achieve state selection, and have low excitation efficiency. The excitation by a non-coherent light source is limited by a saturation limit of 50%. The pulse adiabatic excitation method can achieve an excitation efficiency close to 100%, and has made significant progress in realizing high efficiency and robust quantum state population transfer. However, the inherent limitation of the pulse laser excitation of the molecular beam is that it can only excite a small area of the molecular beam, and there is a lack of spatial coverage. Although the single excitation efficiency of the pulse laser is extremely high, the pulse laser scheme cannot meet the needs of scenarios that require large flux and large area excitation.

[0004] Therefore, how to use continuous laser to overcome the spatial limitation of the pulse adiabatic excitation scheme is a problem that needs to be solved at present. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a single quantum state molecular beam preparation system, device and method, which can solve the problem that the excitation area of the molecular beam by the existing adiabatic excitation scheme is small and the spatial coverage is bottlenecked.

[0006] According to a single quantum state molecular beam preparation system according to an embodiment of the present application, comprising: A molecule excitation module, the molecule excitation module comprising a gas inlet pipeline and a molecular beam valve, the gas inlet pipeline being used for injecting gas molecules to be excited into the molecular beam valve, and the molecular beam valve being used for reducing the gas molecules of multiple quantum states to a ground state to obtain a ground state molecular beam; A laser output module, the laser output module comprising a laser source assembly and a cylindrical convex lens, the laser source assembly being used for outputting continuous laser, the continuous laser passing through the cylindrical convex lens to obtain fan-shaped excitation laser, and the excitation laser intersecting with the ground state molecular beam perpendicularly to the flight direction of the ground state molecular beam.

[0007] According to a single quantum state molecular beam preparation system according to an embodiment of the present application, at least the following beneficial effects are achieved: The application changes the wavefront curvature of the continuous laser by setting the cylindrical convex lens, so that the mutually parallel wavefronts become arc-shaped, the ground state molecular beam intersects with the fan-shaped excitation laser, and due to the Doppler effect, the photons of the excitation laser are subjected to Doppler frequency shift during the flight of the gas molecules, so that the dynamic frequency scanning in the spatial dimension is naturally realized, thereby meeting the frequency chirp condition required by the adiabatic excitation, so that the molecular beam can be prepared by the continuous laser, the spatial coverage bottleneck of the existing pulse laser is overcome, and high-efficiency, large-flux and large-area molecular beam excitation is realized.

[0008] According to some embodiments of the application, the laser source assembly comprises a laser, a laser amplifier and an optical parametric oscillator arranged in sequence, the laser amplifier is used for energy amplification of seed laser output by the laser, and the optical parametric oscillator is used for nonlinear conversion of the amplified seed laser to obtain the continuous laser.

[0009] According to some embodiments of the application, the laser source is provided with a piezoelectric ceramic, which is used for adjusting the wavelength of the laser source according to the received voltage signal.

[0010] According to some embodiments of the application, a wavelength feedback module is further included, which feeds back the voltage signal of the piezoelectric ceramic according to the wavelength of the excitation laser, so as to fix the wavelength of the excitation laser at the resonant absorption wavelength of the gas molecules, a first beam splitter is arranged on the propagation path of the continuous laser, and a part of the continuous laser after passing through the first beam splitter enters the wavelength feedback module as feedback laser.

[0011] According to some embodiments of the application, the wavelength feedback module comprises a second beam splitter and a wavemeter, part of the feedback laser after passing through the second beam splitter is incident on the wavemeter, and the wavemeter is used for measuring the wavelength of the feedback laser.

[0012] According to some embodiments of the application, the wavelength feedback module comprises a third beam splitter, a detection modulation assembly, a gas absorption cell and a mirror, part of the feedback laser transmits through the third beam splitter and enters the gas absorption cell, the gas absorption cell is filled with the gas molecules, the mirror is arranged at one end of the gas absorption cell away from the third beam splitter, and the feedback laser is reflected by the third beam splitter to the detection modulation assembly after passing through the gas absorption cell back and forth.

[0013] According to some embodiments of the application, the detection modulation assembly comprises a photodetector and a signal modulation processor, the photodetector is used for detecting light intensity and converting it into an electric signal, and the signal modulation processor is used for receiving the electric signal output by the photodetector, calculating and processing, and outputting the voltage signal to the piezoelectric ceramic.

[0014] According to some embodiments of the present application, the detection modulation assembly further comprises a signal amplifier and a voltage amplifier, the signal amplifier is used for amplifying the electrical signal output by the photodetector, and the voltage amplifier is used for amplifying the voltage signal output by the signal modulation processor.

[0015] According to a second aspect of the present application, a preparation device comprises the single quantum state molecular beam preparation system.

[0016] According to a third aspect of the present application, a preparation method is suitable for the preparation device, and the preparation method comprises the following steps: inputting the gas molecules by the gas inlet pipeline, and obtaining the ground state molecular beam by adiabatic expansion of the gas molecules by the molecular beam valve. The laser output module outputs the fan-shaped excitation laser perpendicular to the flight direction of the ground state molecular beam. The wavelength of the excitation laser, the relative distance between the cylindrical convex lens and the ground state molecular beam, and the focal length of the cylindrical convex lens are adjusted so that the excitation efficiency is the highest. The excitation laser adiabatically excites the ground state molecular beam to obtain an excited state molecular beam.

[0017] Other features and advantages of the present application will be illustrated in the following description, and some will become apparent from the description, or will be understood by those skilled in the art through implementation of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0018] The present application will be further described below in combination with the drawings and examples, wherein: Figure 1 Structure schematic diagram of an embodiment of the single quantum state molecular beam preparation system provided by the present application; Figure 2 Schematic diagram of the propagation direction of the excitation laser and the flight direction of the molecular beam in the single quantum state molecular beam preparation system provided by the present application; Figure 3 In the single quantum state molecular beam preparation system provided by the present application, a graph of the photon energy and time relationship during the flight of the molecules.

[0019] Reference numerals: Molecular excitation module 100; gas inlet pipeline 110; molecular beam valve 120; Laser output module 200; 45° reflector 201; laser 211; laser amplifier 212; optical parametric oscillator 213; cylindrical convex lens 221; half-wave plate 222; Wavelength feedback module 300; piezoelectric ceramic 301; first beam splitter 302; second beam splitter 311; wavemeter 312; third beam splitter 321; gas absorption cell 322; mirror 323; photodetector 331; signal amplifier 332; signal modulation processor 333; voltage amplifier 334. DETAILED DESCRIPTION

[0020] Embodiments of the present application are described below in detail with reference to the accompanying drawings, wherein the same or similar components are denoted by the same or similar reference numerals throughout the drawings. The embodiments described below by reference to the drawings are exemplary and are for the purpose of explaining the present application only, and should not be understood as limiting the present application.

[0021] In the description of the present application, it should be understood that the orientation description, such as the up, down, etc. indicates the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be understood as limiting the present application.

[0022] In the description of the present application, plural means more than two. If there is a description of first, second, it is only for the purpose of distinguishing technical features, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the sequence of technical features indicated.

[0023] In the description of the present application, unless otherwise explicitly limited, the words such as arrangement, installation, connection, etc. should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0024] The technical solutions of the present application will be described below in conjunction with the drawings. Obviously, the following described embodiments are part of the embodiments of the present application, not all embodiments.

[0025] In many reaction systems, the quantum state structure of the reactant molecules, especially the vibrationally excited state, has a key influence on the path selection, energy barrier crossing and product distribution of chemical reactions, therefore, it is extremely important for molecular reaction dynamics research to prepare a specific quantum state molecular beam with high purity and controllable population.

[0026] At present, traditional thermal excitation, discharge excitation and other methods are difficult to realize state selection, and the excitation efficiency is low, the non-coherent light source excitation is limited by the saturation limit of 50%, the pulse adiabatic excitation method can realize the excitation efficiency close to 100%, and significant progress has been made in realizing high efficiency and robust quantum state population transfer, but the scheme uses pulse laser to realize the excitation of the molecular beam, and its inherent limitation is that it can only excite a small area of the molecular beam, and there is a lack of spatial coverage, although the single excitation efficiency of the pulse laser is extremely high, but for the scene that needs large flux and large area excitation, the pulse laser scheme cannot meet the demand.

[0027] Therefore, how to use continuous laser to overcome the spatial limitation of the pulse adiabatic excitation scheme is a problem to be solved at present.

[0028] In order to solve the above problems, the present application provides a single quantum state molecular beam preparation system, device and method, which can solve the problem that the existing adiabatic excitation scheme has a small excitation area of the molecular beam and a bottleneck in spatial coverage.

[0029] Reference Figure 1 、 Figure 2 and Figure 3 The single quantum state molecular beam preparation system of the present application makes the following embodiments: The single quantum state molecular beam preparation system of the present application includes a molecular excitation module 100, a laser output module 200 and a wavelength feedback module 300.

[0030] The molecular excitation module 100 is used to provide a ground state molecular beam, the laser output module 200 is used to emit continuous excitation laser perpendicular to the flight direction of the ground state molecular beam, wherein the excitation laser is a fan-shaped laser focused in the transverse direction by the cylindrical convex lens 221, the ground state molecular beam emitted by the molecular excitation module 100 is adiabatically excited, thereby realizing high-efficiency excitation in a continuous spatial domain, and the wavelength feedback module 300 is used to adjust the wavelength feedback of the laser output module 200, so that the wavelength of the laser output by the laser output module 200 is locked at the resonant absorption wavelength of the target single quantum state level of the gas molecules.

[0031] The present application utilizes the Doppler effect, changes the wavefront curvature of the continuous laser by the cylindrical convex lens 221, so that the mutually parallel wavefronts become arc-shaped, the ground state molecular beam intersects with the fan-shaped excitation laser, and the photons of the excitation laser are subjected to Doppler frequency shift during the flight of the gas molecules, thereby naturally realizing dynamic frequency scanning in the spatial dimension, satisfying the frequency chirp condition required by adiabatic excitation, exciting the ground state molecular beam to the target single quantum state level, so that the molecular beam can be prepared by continuous laser, overcoming the spatial coverage bottleneck of the existing pulse laser, and realizing high-efficiency, large-flux and large-area molecular beam excitation.

[0032] Specifically, the molecular excitation module 100 includes an inlet pipe 110 and a molecular beam valve 120. The inlet pipe 110 is used to inject the gas molecules to be excited into the molecular beam valve 120. The molecular beam valve 120 is a container that can withstand several to tens of atmospheres of pressure. It has a small orifice nozzle at the top with an aperture of tens of micrometers. When the molecular beam valve 120 diffuses the gas molecules to be excited from the nozzle into the vacuum, due to adiabatic expansion, the gas molecules in different quantum states in the inlet pipe 110 are cooled and converted to the lowest quantum state, resulting in a ground state molecular beam with a single quantum state, good directionality, and good velocity monochromaticity. This facilitates subsequent adiabatic excitation with a continuous laser of the same wavelength to reach the target single quantum state.

[0033] The laser output module 200 includes a laser source component and a cylindrical convex lens 221. The laser source component is used to output continuous laser light. The cylindrical convex lens 221 is located on the propagation path of the continuous laser light. It focuses the light in the horizontal dimension without changing the beam divergence in the vertical dimension, thereby improving the spatial matching accuracy and obtaining a fan-shaped excitation laser light. The excitation laser light is perpendicular to the flight direction of the ground state molecular beam and intersects with the ground state molecular beam.

[0034] Reference Figure 2 As shown, during the flight of the ground-state molecular beam, due to the Doppler effect, in the first stage, the excitation laser has a component opposite to the flight direction of the ground-state molecular beam; in the second stage, the wavefront of the excitation laser is exactly tangent to the flight direction of the ground-state molecular beam, and the excitation laser has no component in the flight direction; in the third stage, the excitation laser has a component in the same direction as the flight direction of the ground-state molecular beam.

[0035] Reference Figure 3 As shown, the photon energy of the excitation laser is locked at the molecular transition energy level of the target single quantum state. ,but The moment corresponds to the first stage, when the ground-state molecular beam intersects with the excitation laser, it experiences a difference higher than the molecular energy level. of ; The moment corresponds to the second stage, when the ground-state molecular beam intersects with the excitation laser and senses the molecular energy level difference E0; The moment corresponds to the first stage, when the ground-state molecular beam intersects with the excitation laser, it experiences a difference lower than the molecular energy level. of This allows photon energy and molecular absorption energy levels to intersect in time, and during this process, the laser energy is not zero. When the laser intensity is strong enough, the adiabatic excitation condition is met, and the molecular population is reversed to achieve 100% vibrational excitation.

[0036] The application applies the Doppler effect as an active control mechanism, converts a physical phenomenon usually regarded as interference (such as causing spectral line broadening) into a key means for achieving adiabatic excitation, enables continuous wave laser to simulate the frequency chirp capability of pulsed laser, thereby achieving efficient excitation in continuous spatial domain, simplifying the control steps without matching the timing for pulsed molecular beam excitation, and enabling the whole molecular beam to be excited for continuous molecular beam excitation, thereby breaking through the space coverage bottleneck of the pulsed laser adiabatic excitation scheme and achieving high-efficiency, large-flux and large-area molecular beam excitation.

[0037] Referring to Figure 2 As shown in the figure, Wx(0) is the waist of laser focusing, Wx(z) is 1 / 2 of the region where the laser interacts with the molecular beam, z is the distance between the ground state molecular beam and the cylindrical convex lens 221, and f is the focal length of the cylindrical convex lens 221. It is necessary to obtain a stable excitation interval by adjusting z and f.

[0038] When z increases, the energy width that can be scanned increases , so that the molecular beam with a wider absorption line width can be excited to the upper state, but at the same time, the cross section of the laser beam will be increased, thereby reducing the laser power density, possibly destroying the adiabatic excitation condition, and leading to a decrease in the molecular beam excitation efficiency; when f increases, the cross section of the laser beam will be reduced, thereby increasing the power density of the laser, which is beneficial to the realization of adiabatic excitation; however, the increase of f will result in a smaller wavefront curvature of the laser, thereby reducing the scanned energy width ΔE, so that only the molecular beam with a very small absorption line width can be excited, and in actual application, the distance z and the focal length f need to be comprehensively adjusted to improve the excitation efficiency of the ground state molecular beam, so as to obtain a condition interval in which efficient and stable excitation can be achieved.

[0039] Further, the specific structure of the laser source assembly is that the laser source assembly comprises a laser 211, a laser amplifier 212 and an optical parametric oscillator 213 arranged in sequence, the laser 211 is used for outputting seed laser, the seed laser of the embodiment of the application is a milliwatt-level 1064nm tunable laser, the laser amplifier 212 is used for amplifying the energy of the seed laser output by the laser 211, and a single longitudinal mode narrow line width laser of 10-100W level is output, which provides pump light for the subsequent optical parametric oscillator 213, and the optical parametric oscillator 213 is used for nonlinear conversion of the single longitudinal mode narrow line width laser to obtain high-energy narrow line width tunable single longitudinal mode infrared laser as continuous laser.

[0040] In the embodiment of the application, a half-wave plate 222 is further arranged between the laser source assembly and the cylindrical convex lens 221, the half-wave plate 222 is arranged in a 360° rotation adjustable manner perpendicular to the propagation direction 360° of the continuous laser, and is used for changing the polarization direction of the laser until the polarization state matched with the absorption of the ground state molecular beam is reached. ​

[0041] Furthermore, two 45° reflectors 323201 are provided between the half-wave plate 222 and the laser source assembly to reflect the continuous laser, change the optical path, compress and optimize the system structure, and improve compactness.

[0042] The laser 211 of this invention includes a piezoelectric ceramic 301 for adjusting the wavelength of the laser source according to the received voltage signal. A voltage is applied to the piezoelectric ceramic 301, and the length of the piezoelectric ceramic 301 changes when the voltage changes. This change in the length of the piezoelectric ceramic 301 tunes the seed laser, changing its wavelength, and thus controlling the wavelengths of the continuous laser and the excitation laser. The present invention also includes a wavelength feedback module 300, which provides voltage signal feedback to the piezoelectric ceramic 301 according to the wavelength of the excitation laser, so as to fix the wavelength of the excitation laser at the resonant absorption wavelength of the gas molecules, thereby obtaining a wavelength-stable excitation laser output.

[0043] A first beam splitter 302 is provided on the light-emitting side of the laser source assembly. Most of the continuous laser light is transmitted through the first beam splitter 302 and propagates to the half-wave plate 222 and the cylindrical convex lens 221. A small portion is reflected by the first beam splitter 302 and used as feedback laser light for the input wavelength feedback module 300.

[0044] The wavelength feedback module 300 is equipped with a wavelength meter 312. A second beam splitter 311 is provided on the incident light side of the wavelength meter 312. Part of the feedback laser is transmitted through the second beam splitter 311, and part of it is reflected by the second beam splitter 311 into the wavelength meter 312. The wavelength meter 312 is used to measure the wavelength of the continuous laser to coarsely adjust the wavelength of the continuous laser and modulate it to near the resonant absorption wavelength of the single quantum state energy level of the gas molecule target.

[0045] The wavelength feedback module 300 also includes a third beam splitter 321, a detection and modulation component, a gas absorption cell 322, and a reflector 323. The feedback laser portion that has passed through the second beam splitter 311 passes through the third beam splitter 321 and enters the gas absorption cell 322, which is filled with gas molecules. The reflector 323 is located at the end of the gas absorption cell 322 away from the third beam splitter 321. After the feedback laser passes back and forth through the gas absorption cell 322, it is reflected by the third beam splitter 321 to the detection and modulation component.

[0046] The detection modulation assembly comprises, in sequence, a photodetector 331, a signal amplifier 332, a signal modulation processor 333 and a voltage amplifier 334, the feedback laser after reflection enters the photodetector 331, the photodetector 331 converts the detected optical signal into an electrical signal, the signal amplifier 332 is used for amplifying the electrical signal, the signal modulation processor 333 outputs a voltage signal after calculation and processing of the amplified electrical signal, and the voltage signal is amplified by the voltage amplifier 334 and then applied to the piezoelectric ceramic 301, so that the wavelength of the seed laser is tuned through the deformation of the piezoelectric ceramic 301, and the wavelength of the excitation laser is adjusted and controlled.

[0047] For the specific adjustment steps of the wavelength feedback module 300, first, the wavelength of the continuous laser is detected by using the wavemeter 312, and the continuous laser is coarsely adjusted; the signal modulation processor 333 fine-tunes the wavelength of the seed laser by outputting a rapidly increasing and decreasing weak voltage signal, so that the wavelengths of the continuous laser and the feedback laser change, the feedback laser with different wavelengths is reflected by the mirror 323 after passing through the gas absorption cell 322, realizes the return incidence into the gas absorption cell 322, and according to the principle of Lamb dip, an extreme value is obtained at the center of the gas molecular absorption energy level, and the signal will be increased when the wavelength is increased or decreased.

[0048] The signal modulation processor 333 rapidly adjusts and outputs the voltage to change the wavelength, collects the electrical signals of the absorption of different wavelengths by the molecules, and derives the electrical signals, so that the signal is locked at the position of the reciprocal of zero, that is, the resonant absorption wavelength of the single quantum state energy level of the gas molecules, so that the wavelength of the continuous laser is locked at the resonant absorption energy level of the gas molecules, that is, the excitation laser is accurately locked at the resonant absorption wavelength of the single quantum state energy level of the gas molecules.

[0049] The present application introduces the principle of Lamb dip to assist in locking the wavelength of the laser by designing a closed-loop control system and constructing an automatic feedback closed loop.

[0050] Further, the present application also provides a preparation device comprising the above-mentioned single quantum state molecular beam preparation system, which has all the advantages of the single quantum state molecular beam preparation system.

[0051] The present application also provides a preparation method suitable for the above-mentioned preparation device, and the preparation method comprises: S100: The gas molecules are input into the gas pipeline 110, and the molecular beam valve 120 is used for adiabatic expansion of the gas molecules to obtain a ground state molecular beam; S200: The laser output module 200 outputs a fan-shaped excitation laser perpendicular to the flight direction of the ground state molecular beam; S300: Adjust the wavelength of the excitation laser, the relative distance between the cylindrical convex lens 221 and the ground state molecular beam, and the focal length of the cylindrical convex lens 221, so that the excitation efficiency is the highest. S400: The ground state molecular beam is adiabatically excited by the excitation laser to obtain an excited state molecular beam.

[0052] In step S100, the gas molecules of different quantum states are adiabatically expanded by the molecular beam valve 120, the gas molecules are cooled to form a rotational-vibrational ground state molecule, and the quantum states of the gas molecules are unified, which is beneficial to improve the purity of the molecular beam.

[0053] In step S200, the seed laser is amplified and nonlinearly converted by the laser output module 200 to improve the light intensity, optimize the polarization and limit the wavelength linewidth, and obtain a high-energy narrow-linewidth tunable single-longitudinal-mode infrared laser as a continuous laser. The cylindrical convex lens 221 focuses the continuous laser in the transverse direction to change the wavefront shape and obtain a fan-shaped excitation laser.

[0054] In step S300, the wavelength is automatically modulated by the wavelength feedback module 300 to lock the excitation laser wavelength at the resonant absorption wavelength of the target single quantum state of the gas molecules. The relative distance between the cylindrical convex lens 221 and the ground state molecular beam and the focal length of the cylindrical convex lens 221 are adjusted to optimize the scanned energy width while ensuring that the adiabatic excitation condition is not destroyed.

[0055] In step S400, the ground state molecular beam intersects with the fan-shaped excitation laser. Due to the Doppler effect, the photons of the excitation laser are subjected to Doppler frequency shift during the flight of the gas molecules, thereby naturally realizing dynamic frequency scanning in the spatial dimension, thereby meeting the frequency chirp condition required by the adiabatic excitation. This makes it possible to prepare a molecular beam by using a continuous laser, overcoming the spatial coverage bottleneck of the existing pulsed laser, and realizing high-efficiency, high-throughput, and large-area molecular beam excitation.

[0056] It should be understood that parts of the present application can be realized by hardware, software, firmware or a combination thereof. In the above embodiments, a plurality of steps or methods can be realized by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if realized by hardware, and as in another embodiment, it can be realized by any one or a combination of the following technologies known in the art: discrete logic circuit with logic gate circuit for implementing logic function on data signal, application specific integrated circuit with suitable combination logic gate circuit, programmable gate array (PGA), field programmable gate array (FPGA), etc.

[0057] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0058] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A single quantum state molecular beam preparation system, comprising: The system comprises: a molecule excitation module, comprising an air inlet pipeline and a molecular beam valve, the air inlet pipeline being used for injecting gas molecules to be excited into the molecular beam valve, and the molecular beam valve being used for reducing the gas molecules of multiple quantum states to a ground state to obtain a ground state molecular beam; a laser output module, the laser output module comprising a laser source assembly and a cylindrical convex lens, the laser source assembly being used for outputting continuous laser, and the continuous laser passing through the cylindrical convex lens to obtain fan-shaped excitation laser, the excitation laser intersecting with the ground state molecular beam perpendicularly to the flight direction of the ground state molecular beam.

2. The single quantum state molecular beam preparation system according to claim 1, wherein: the laser source assembly comprises a laser, a laser amplifier and an optical parametric oscillator arranged in sequence, the laser amplifier being used for energy amplification of seed laser output by the laser, and the optical parametric oscillator being used for nonlinear conversion of the amplified seed laser to obtain the continuous laser.

3. The single quantum state molecular beam preparation system according to claim 2, wherein: the laser source is provided with a piezoelectric ceramic, the piezoelectric ceramic being used for adjusting the wavelength of the laser source according to the received voltage signal.

4. The single quantum state molecular beam preparation system according to claim 3, wherein: a wavelength feedback module is further included, the wavelength feedback module being used for voltage signal feedback to the piezoelectric ceramic according to the wavelength of the excitation laser, so as to fix the wavelength of the excitation laser at the resonant absorption wavelength of the gas molecules, a first beam splitter being arranged on the propagation path of the continuous laser, and a part of the continuous laser after passing through the first beam splitter enters the wavelength feedback module as feedback laser.

5. The single quantum state molecular beam preparation system according to claim 4, wherein: the wavelength feedback module comprises a second beam splitter and a wavemeter, a part of the feedback laser after passing through the second beam splitter is incident to the wavemeter, and the wavemeter is used for measuring the wavelength of the feedback laser.

6. The single quantum state molecular beam preparation system according to claim 4 or 5, wherein: the wavelength feedback module comprises a third beam splitter, a detection modulation assembly, a gas absorption cell and a reflector, a part of the feedback laser is transmitted through the third beam splitter to enter the gas absorption cell, the gas absorption cell is filled with the gas molecules, the reflector is arranged at one end of the gas absorption cell away from the third beam splitter, and the feedback laser is reflected by the third beam splitter to the detection modulation assembly after passing through the gas absorption cell back and forth.

7. The single quantum state molecular beam preparation system according to claim 6, wherein: the detection modulation assembly comprises a photodetector and a signal modulation processor, the photodetector is used for detecting light intensity and converting it into an electric signal, and the signal modulation processor is used for receiving the electric signal output by the photodetector, calculating and processing, and then outputting the voltage signal to the piezoelectric ceramic.

8. The single quantum state molecular beam preparation system according to claim 7, wherein: The detection modulation assembly further comprises a signal amplifier configured to amplify the electrical signal output by the photodetector and a voltage amplifier configured to amplify the voltage signal output by the signal modulation processor.

9. A preparation device characterized by: A single quantum state molecular beam preparation system as claimed in any one of claims 1 to 8.

10. A preparation method suitable for use in the preparation apparatus of claim 9, the preparation method comprising: The gas molecules are input into the gas inlet pipeline, and the molecular beam valve is configured to adiabatically expand the gas molecules to obtain the ground state molecular beam; The laser output module is configured to output the fan-shaped excitation laser perpendicular to the flight direction of the ground state molecular beam; The wavelength of the excitation laser, the relative distance between the cylindrical convex lens and the ground state molecular beam, and the focal length of the cylindrical convex lens are adjusted so that the excitation efficiency is maximized; The excitation laser is configured to adiabatically excite the ground state molecular beam to obtain the excited state molecular beam.

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