Method and system for measuring atomic beam current velocity

Abstract

The application discloses a kind of method and system for measuring atomic beam flow velocity, the method excites the atom in ground state in the first resonance laser in the second resonance action area, and the first resonance laser is the laser that frequency is locked on the first resonance transition spectral line of atom;After the intensity of detected fluorescent signal reaches the first stable amplitude value, the atom in ground state in the first resonance action area is excited by the second resonance laser at the first time point, and the second time point when fluorescent signal intensity starts to weaken is determined, the second resonance laser is the laser that frequency is locked on the second resonance transition spectral line of atom, and the excited state energy level lifetime of the second resonance transition spectral line of atom is longer than the first resonance transition spectral line;According to the determined atomic transit displacement and atomic transit time, the velocity information of atomic beam flow is determined.The application solves the problem that the previous experiment calculates the velocity of atomic beam flow, and the measurement precision is poor, the reliability is low, and the practical measurement verification is lacked.

Description

Technical Field

[0001] This invention relates to the field of atomic physics, and more specifically to a method and system for measuring the velocity of an atomic beam. Background Technology

[0002] In atomic physics, atomic beams are frequently used to conduct experiments related to resonant transitions caused by the interaction of atoms with lasers. The atomic beam exits from the furnace, enters the interaction region, interacts with the resonant light, and emits photons. These photons are collected by a fluorescence collector, and the atomic transition spectral lines are detected. The transit time broadening caused by atomic velocity is one of the main factors affecting the linewidth of atomic transition spectral lines. In atomic clock systems, the linewidth of atomic transition spectral lines directly affects the frequency stability of the system. Previous experiments generally estimated the atomic beam velocity from the furnace temperature or the atomic beam temperature, but this method had poor measurement accuracy, low reliability, and lacked empirical verification. Summary of the Invention

[0003] The purpose of this invention is to provide a method and system for measuring atomic beam velocity, in order to solve the problems mentioned in the related art, such as poor measurement accuracy, low reliability and lack of experimental verification in previous experiments for estimating atomic beam velocity.

[0004] To achieve the above objectives, a first aspect of the present invention provides a method for measuring the velocity of an atomic beam, comprising:

[0005] The atomic beam to be tested is emitted and the atomic beam is made to pass through the first resonance region and the second resonance region in sequence.

[0006] Atoms in the ground state within the second resonance region are excited using a first resonant laser, and the fluorescence signal intensity generated by the spontaneous emission of photons from the excited atoms in the second resonance region falling back to the ground state is detected. The first resonant laser is a laser whose frequency is locked to the first resonant transition spectral line of the atom.

[0007] After the detected fluorescence signal intensity reaches a first stable amplitude value, the atoms in the ground state in the first resonance region are excited by a second resonant laser at a first time point, and the time point at which the fluorescence signal intensity begins to weaken is determined as the second time point. The second resonant laser is a laser whose frequency is locked on the second resonant transition spectral line of the atom, and the lifetime of the excited state energy level of the second resonant transition spectral line of the atom is longer than the lifetime of the excited state energy level of the first resonant transition spectral line.

[0008] The atomic transit displacement is determined based on the distance between the atomic excitation positions in the second resonance region and the atomic excitation positions in the first resonance region, and the atomic transit time is determined based on the interval between the first time point and the second time point.

[0009] The velocity information of the atomic beam is determined based on the atomic transit displacement and the atomic transit time.

[0010] In some embodiments, the method further includes:

[0011] Obtain the estimated velocity of the atomic beam to be measured, and obtain the detection response delay generated before detecting the intensity of the fluorescence signal;

[0012] The upper limit of the atomic transition displacement is determined based on the lifetime of the excited state level of the second resonance transition spectral line of the atom and the velocity estimate.

[0013] The lower limit of the atomic transit displacement is determined based on the detection response delay and the velocity estimate.

[0014] In some embodiments, the method further includes:

[0015] The response delay time detected before the second resonant laser excites atoms in the ground state within the second resonant region is obtained;

[0016] Then, determining the atom transit time based on the interval between the first time point and the second time point includes:

[0017] The time obtained by subtracting the response delay time from the first time point is taken as the actual excitation time point of the atoms in the ground state in the first resonance region by the second resonant laser.

[0018] The atomic transit time is determined based on the interval between the actual excitation time and the second time point.

[0019] In some embodiments, the second time point further includes a third time point corresponding to a predetermined percentage of the first stable amplitude value, and the third time point is later than the second time point.

[0020] A second aspect of the present invention provides a system for measuring the velocity of an atomic beam, comprising:

[0021] An atomic beam providing device is used to emit an atomic beam to be tested, and the atomic beam providing device is provided with a first resonance region and a second resonance region in sequence along the emission direction of the atomic beam.

[0022] An optical device for providing a first resonant laser and a second resonant laser;

[0023] The main control device is connected to the optical device and is used to control the first resonant laser to excite atoms in the ground state in the second resonant region and detect the signal intensity of fluorescence generated by the spontaneous emission of photons from the excited atoms in the second resonant region falling back to the ground state.

[0024] After the intensity of the fluorescence signal detected by the main control device reaches a first stable amplitude value, it controls the second resonant laser to excite the atoms in the ground state in the first resonant region at a first time point.

[0025] A frequency locking component is connected between the optical device and the main control device. The main control device controls the frequency locking component to lock the frequency of the first resonant laser provided by the optical device onto the first resonant transition spectral line of the atom, and the frequency of the second resonant laser onto the second resonant transition spectral line of the atom.

[0026] In some embodiments, the main control device includes:

[0027] A computer device connected to the optical device and the frequency locking component, wherein the computer device controls the first resonant laser to excite atoms in the ground state in the second resonant region, and controls the second resonant laser to excite atoms in the ground state in the first resonant region at a first time point, and the computer device controls the frequency locking component to lock the frequency of the first resonant laser provided by the optical device to the first resonant transition line of the atom, and the frequency of the second resonant laser to the second resonant transition line of the atom;

[0028] A signal detector is installed in the second resonant region and connected to the computer device, which controls the signal detector to detect the intensity of the fluorescence signal.

[0029] In some embodiments, the frequency locking assembly includes a frequency locker and a wavelength meter, and the optical device includes:

[0030] A first optical module is used to provide the second resonant laser;

[0031] A second optical module is used to provide the first resonant laser;

[0032] Both the first optical module and the second optical module include a laser, a laser adjustment component, a fiber collimator, a mechanical switch, and a reflector;

[0033] The frequency lock is connected between the laser and the computer device;

[0034] The laser adjustment component is positioned in the direction of the laser emitted by the laser. After being adjusted by the laser adjustment component, the laser emits transmitted light and reflected light. The fiber collimator is positioned in the direction of the transmitted light emitted by the laser adjustment component. The mechanical switch and the reflector are sequentially positioned in the direction of the reflected light emitted by the laser adjustment component.

[0035] The mechanical switch is connected to the computer device and is controlled to be turned on by the computer device;

[0036] The fiber collimator is connected to the wavelength meter.

[0037] In some of these embodiments, the laser modulation assembly includes a half-wave plate and a polarizing beam splitter.

[0038] In some embodiments, the main control device further includes a data acquisition module connected between the computer device and the signal detector, wherein the computer device controls the data acquisition module to acquire the intensity of the fluorescence signal detected by the signal detector.

[0039] In some embodiments, both the first and second resonant regions of the atomic beam providing device are provided with laser incident windows.

[0040] Compared with the prior art, the technical solution provided in this application has at least the following technical effects:

[0041] This invention utilizes the atomic transit time and atomic transit displacement obtained after atoms interact with two discrete resonant laser beams to measure the atomic beam velocity, filling the gap in the practical verification of atomic beam velocity. The measurement accuracy is high and the reliability is high. Attached Figure Description

[0042] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0043] Figure 1 This is a flowchart illustrating a method for measuring atomic beam velocity according to an embodiment of the present invention.

[0044] Figure 2 The present invention provides a method for determining the upper and lower limits of atomic transit displacement;

[0045] Figure 3 A schematic diagram of a system for measuring atomic beam velocity is provided in another embodiment of the present invention;

[0046] Figure 4This is a schematic diagram illustrating the determination of atomic transit displacements in this invention.

[0047] Explanation of reference numerals in the attached figures:

[0048] 10. Atomic beam supply device; 11. Atomic furnace; 12. First resonance region; 13. Second resonance region; 14. Laser incident window; 20. Optical device; 21. First optical module; 101. First laser; 102. First half-wave plate; 103. First polarizing beam splitter; 104. First fiber collimator; 105. First mechanical switch; 106. First reflector; 22. Second optical module; 201. Second laser; 202. Second half-wave plate; 203. Second polarizing beam splitter; 204. Second fiber collimator; 205. Second mechanical switch; 206. Second reflector; 31. Computer equipment; 32. Data acquisition module; 33. Photodetector; 40. Wavelength meter; 50. Frequency lockout. Detailed Implementation

[0049] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and are not to a precise scale, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0050] It should be noted that, in order to clearly illustrate the content of this invention, several embodiments are provided to further explain different implementations of the invention. These embodiments are enumerated rather than exhaustive. Furthermore, for the sake of brevity, content mentioned in the preceding embodiments is often omitted in the following embodiments. Therefore, content not mentioned in the later embodiments can be referred to in the preceding embodiments.

[0051] In a first embodiment of the present invention, a method for measuring the velocity of an atomic beam is provided, such as... Figure 1 As shown, it includes the following steps:

[0052] Step S11: Emit the atomic beam to be tested, and make the atomic beam pass through the first resonance region 12 and the second resonance region 13 in sequence.

[0053] Step S12: The atoms in the ground state in the second resonance region 13 are excited by the first resonance laser, and the signal intensity of the fluorescence generated by the spontaneous emission of photons from the excited atoms in the second resonance region 13 falling back to the ground state is detected. The first resonance laser is a laser whose frequency is locked on the first resonance transition line of the atom.

[0054] Step S13: After the detected fluorescence signal intensity reaches the first stable amplitude value, the atoms in the ground state in the first resonance region 12 are excited by the second resonance laser at the first time point, and the time point at which the fluorescence signal intensity begins to weaken is determined as the second time point. The second resonance laser is a laser whose frequency is locked to the second resonance transition spectral line of the atom, and the lifetime of the excited state energy level of the second resonance transition spectral line of the atom is longer than the lifetime of the excited state energy level of the first resonance transition spectral line, so that when the atom excited by the second resonance laser moves to the second resonance region 13, it is still in the excited state. The excited state atom does not interact with the first resonance laser in the second resonance region 13, thereby reducing the number of atoms in the second resonance region 13 that resonate with the first resonance laser.

[0055] Step S14: Determine the atomic transit displacement based on the distance between the atomic excitation positions in the second resonance region 13 and the atomic excitation positions in the first resonance region 12, and determine the atomic transit time based on the interval between the first time point and the second time point.

[0056] Step S15: Determine the velocity information of the atomic beam based on the atomic transit displacement and atomic transit time.

[0057] To ensure that the atoms excited by the second resonant laser remain in an excited state when they move to the second resonant interaction region 13, such as... Figure 2 As shown, the method provided in this embodiment of the invention further includes the following steps:

[0058] Step S21: Obtain the estimated velocity of the atomic beam to be measured, and obtain the detection response delay generated before detecting the fluorescence signal intensity. If a photodetector is used to detect the fluorescence signal intensity, the detection response delay is the response delay of the photodetector.

[0059] Step S22: Based on the lifetime and velocity estimate of the excited state level of the second resonance transition spectrum of the atom, determine the upper limit of the atomic transition displacement. Specifically, the upper limit of the displacement is the product of the lifetime and velocity estimate of the excited state level of the second resonance transition spectrum.

[0060] Step S23: Based on the detection response delay and velocity prediction, determine the lower limit of the atomic transit displacement. Specifically, the lower limit is the product of the detection response delay and the velocity prediction. That is, the atomic transit displacement must be less than the upper limit and greater than the lower limit to ensure that the atoms excited in the first resonance region 12 remain excited in the second resonance region 13 and do not interact with the first resonance laser. This reduces the number of atoms in the second resonance region 13 that resonate with the first resonance laser, thus weakening the detected fluorescence signal intensity.

[0061] To improve the accuracy of atomic beam velocity information measurement, the method provided in this embodiment of the invention further includes the following steps: before obtaining the response delay time detected before the second resonant laser excites the atoms in the ground state in the second resonant region 13 (the response delay time is the response delay time of the mechanical switch in the second embodiment), the atomic transit time is determined according to the interval between the first time point and the second time point. Specifically, this includes: taking the time obtained after subtracting the response delay time from the first time point as the actual excitation time point of the atoms in the ground state in the first resonant region 12 excited by the second resonant laser, and determining the atomic transit time according to the interval between the actual excitation time point and the second time point.

[0062] In this embodiment of the invention, depending on different experimental environments or measurement requirements, the second time point may also be selected as the third time point corresponding to the fluorescence signal intensity at a predetermined value of a percentage of the first stable amplitude value, and the third time point is later than the second time point. For example, after the fluorescence signal intensity changes, the time point corresponding to the fluorescence signal intensity at fifty percent of the first stable amplitude value is taken as the value of the second time point, so as to adaptively adjust the measurement error and improve the measurement accuracy.

[0063] This invention utilizes the atomic transit time and atomic transit displacement obtained after atoms interact with two discrete resonant laser beams to measure the atomic beam velocity, filling the gap in the practical verification of atomic beam velocity. The measurement accuracy is high and the reliability is high.

[0064] In the second embodiment of the present invention, as Figure 3 As shown, a system for measuring the velocity of an atomic beam is provided, including an atomic beam supply device 10, an optical device 20, a main control device, and a frequency locking component. The frequency locking component includes a frequency locker 50 and a wavelength meter 40. The atomic beam supply device 10 includes an atomic furnace 11, which is used to emit the atomic beam to be measured. The atomic beam supply device 10 has a first resonance region 12 and a second resonance region 13 arranged sequentially along the emission direction of the atomic beam. Both the first resonance region 12 and the second resonance region 13 are provided with laser incident windows 14.

[0065] Optical device 20 is used to provide a first resonant laser and a second resonant laser. A main control device is connected to optical device 20. The main control device is used to control the first resonant laser to excite atoms in the ground state within the second resonant region 13, and to detect the signal intensity of fluorescence generated when spontaneously emitted photons from excited atoms in the second resonant region 13 fall back to the ground state. After the fluorescence signal intensity detected by the main control device reaches a first stable amplitude value, it controls the second resonant laser to excite atoms in the ground state within the first resonant region 12 at a first time point.

[0066] In this embodiment of the invention, the frequency locker 50 is connected between the optical device 20 and the main control device. The frequency locker 50 can be a PID controller. The main control device controls the PID controller to lock the frequency of the first resonant laser provided by the optical device 20 to the first resonant transition spectrum line of the atom, and the frequency of the second resonant laser to the second resonant transition spectrum line of the atom.

[0067] The main control device includes a computer device 31 and a signal detector. The computer device 31 is connected to the optical device 20. The computer device 31 controls the first resonant laser to excite atoms in the ground state within the second resonant region 13, and controls the second resonant laser to excite atoms in the ground state within the first resonant region 12 at a first time point. The computer device 31 is also connected to a frequency locking component to control the frequency locking component to lock the frequency of the first resonant laser provided by the optical device 20 onto the first resonant transition line of the atom, and the frequency of the second resonant laser onto the second resonant transition line of the atom.

[0068] The signal detector is a photodetector 33 installed in the second resonance region 13. The photodetector 33 is connected to the computer device 31. The computer device 31 controls the photodetector 33 to detect the intensity of the fluorescence signal generated by atomic radiation photons in the second resonance region 13.

[0069] The optical device 20 includes a first optical module 21 for providing a first resonant laser and a second optical module 22 for providing a second resonant laser.

[0070] Both the first optical module 21 and the second optical module 22 include a laser, a laser adjustment component, a fiber collimator, a mechanical switch, and a reflector. A frequency lock 50 is connected between the laser and the computer device 31. The laser adjustment component is positioned in the direction of the laser's output. After adjustment by the laser adjustment component, the laser emits transmitted and reflected light. The fiber collimator is positioned in the direction of the transmitted light emitted by the laser adjustment component. The mechanical switch and the reflector are sequentially positioned in the direction of the reflected light emitted by the laser adjustment component. The first mechanical switch 105 of the first optical module 21 and the second mechanical switch 205 of the second optical module 22 are both connected to the computer device 31. The computer device 31 controls the opening of each mechanical switch to control the resonant laser provided by the corresponding optical module to enter the first resonant region 12 and the second resonant region 13, exciting the atoms in the ground state of the atomic beam.

[0071] Specifically, the first laser 101 of the first optical module 21 and the second laser 201 of the second optical module 22 are both connected to one end of the frequency lock device 50, and the other end of the frequency lock device 50 is connected to the computer device 31. The first fiber collimator 104 of the first optical module 21 and the second fiber collimator 204 of the second optical module 22 are both connected to the wavelength meter 40, which is also connected to the computer device 31. Thus, when the computer device 31 controls the frequency lock device 50 to lock the frequency of each laser onto the atomic transition resonance spectral line, it uses the measurement data from the wavelength meter 40 to determine whether the frequency of each resonant laser is locked onto the predetermined transition resonance spectral line. The laser adjustment component of the first optical module 21 includes a first half-wave plate 102 and a first polarizing beam splitter 103, and the laser adjustment component of the second optical module 22 includes a second half-wave plate 202 and a second polarizing beam splitter 203.

[0072] The main control device also includes a data acquisition module 32, which is connected between the computer device 31 and the photodetector 33. The computer device 31 controls the data acquisition module 32 to acquire the intensity of the fluorescence signal detected by the photodetector 33.

[0073] In the third embodiment of the present invention, the above two embodiments and the appendix are combined. Figures 1 to 4 This paper introduces an atomic beam velocity measurement system and method based on the time-of-flight method.

[0074] The atomic beam velocity measurement system in this embodiment of the invention includes a physical system, an optical system, and an electronic control system. The physical system includes an atomic furnace 11 for emitting the atomic beam, a first resonant region 12, and a second resonant region 13. The optical system includes a first laser 101, a second laser 201, a half-wave plate, a polarizing beam splitter, a mirror, a mechanical switch, an optical fiber collimator, and optical fiber assemblies. The electronic control system includes a photodetector 33, a computer device 31, a wavelength meter 40, and a data acquisition module 32.

[0075] The atomic beam is emitted from the atomic furnace 11, and along the emission direction of the atomic beam, there are a first resonance region 12 and a second resonance region 13. Both regions have laser incident windows 14 for the laser to interact with the atoms in the ground state of the atomic beam. The second resonance region 13 is also provided with a detection window for the photodetector 33 to collect fluorescence signals.

[0076] In the first optical module 21, the second resonant laser emitted from the first laser 101 passes through the first half-wave plate 102 and the first polarizing beam splitter 103. The transmitted light is then coupled into the first fiber collimator 104, transmitted through the fiber to the wavelength meter 40, and then the computer device 31 controls the frequency locker 50 to lock the laser frequency onto the first resonant transition spectral line of the atom. The reflected light (i.e., the second resonant laser) passes through the first mechanical switch 105 and the first reflector 106 and is perpendicularly incident from the first resonant region 12 (about...). Figure 3 and Figure 4 Explanation of perpendicular incidence of laser light: To express the three-dimensional visual effect of the schematic diagram and thus more clearly show the relationship between the parts, this invention includes... Figure 3 and Figure 4 The diagram shows the incident laser with reference to the XYZ coordinate system. Although it does not appear to be perpendicular to the ground plane, it is important to know that each resonant laser is actually perpendicular to the corresponding resonant region, exciting atoms to transition from the ground state to energy levels with longer lifetimes.

[0077] In the second optical module 22, the first resonant laser emitted from the second laser 201 passes through the second half-wave plate 202 and the second polarizing beam splitter 203. The transmitted light is then coupled into the second fiber collimator 204 and transmitted through the fiber to the wavelength meter 40. The computer device 31 controls the frequency locker 50 to lock the laser frequency on the second resonant transition spectrum line of the atom. The reflected light emitted from the second polarizing beam splitter 203 (i.e., the first resonant laser) passes through the second mechanical switch 205 and the second reflecting mirror 206 and is perpendicularly incident from the second resonant region 13, exciting the atom to transition from the ground state to an energy level with a shorter energy level lifetime.

[0078] Please see Figure 4 In this embodiment of the invention, along the emission direction of the atomic beam, the incident positions of the first resonant laser and the second resonant laser have the same light height, and the distance between the incident positions of the first and second resonant lasers is d. In this embodiment, the incident position of the first resonant laser is used as the atomic excitation position within the second resonant region, and the incident position of the second resonant laser is used as the atomic excitation position within the first resonant region. Figure 1 In step S14, the atomic transit displacement is determined by the distance between the atomic excitation positions in the second resonance region and the atomic excitation positions in the first resonance region.

[0079] To measure the fluorescence signal generated when the spontaneous emission photons of excited atoms in the second resonance region 13 fall back to the ground state, a photodetector 33 is installed in the second resonance region 13 to detect the fluorescence signal.

[0080] The computer equipment 31 of the electronic control system controls the data acquisition module 32 to acquire the fluorescence signal of the photodetector 33, and controls the on / off of two mechanical switches in the first optical module 21 and the second optical module 22. All devices in the electronic control system use the same clock reference signal to ensure the triggering synchronization of each control signal.

[0081] Specifically, the atomic beam velocity measurement method based on the time-of-flight method provided in this embodiment of the invention includes the following steps:

[0082] Step 1. The laser frequencies of the first laser 101 and the second laser 201 are controlled by the computer device 31 through the coordinated operation of the frequency lock device 50 and the wavelength meter 40 to lock each laser frequency onto the first resonance transition spectrum line and the second resonance transition spectrum line of the atom, respectively. The excited state energy level lifetime of the first resonance transition spectrum line of the atom is long, and the excited state energy level lifetime of the second resonance transition spectrum line of the atom is short.

[0083] Step 2. The computer device 31 controls the opening of the second mechanical switch 205 in the incident optical path of the first resonant laser. The first resonant laser interacts with the atoms, pumping them to an excited state with a short energy level lifetime. The atoms then spontaneously emit photons from the excited state back to the ground state. The photodetector 33 in the second resonant interaction region 13 detects the atomic fluorescence signal, and the computer device 31 controls the data acquisition module 32 to acquire the signal from the photodetector 33.

[0084] Step 3. Once the computer device 31 obtains a stable initial fluorescence signal (at this point, the fluorescence signal reaches the first stable amplitude value), the computer device 31 controls the opening of the first mechanical switch 105 of the second resonant laser incident light path and records the time point t1 at which the first mechanical switch 105 is triggered. At this time, atoms passing through the first resonant interaction region 12 are excited to the excited state of the first resonant transition spectral line. When the atoms in the excited state of the first resonant transition spectral line continue to move to the second resonant interaction region 13, the number of atoms residing in the ground state decreases, resulting in a decrease in the number of atoms interacting with the second resonant laser, thereby weakening the fluorescence signal.

[0085] Step 4. After the fluorescence signal amplitude stabilizes again, the computer device 31 stops data acquisition.

[0086] Step 5. Process the collected fluorescence signal data and plot the curve of fluorescence signal intensity changing with time. After deducting the effect of the response delay time of the first mechanical switch 105 at time point t1, fit the falling curve of the fluorescence signal intensity. The fitted data can characterize the Gaussian distribution of the atomic beam velocity. Calculate the atomic beam velocity based on the distance d between the two resonant laser beams and the time delay Δt between the fluorescence signal intensity change time point t2 and the trigger time point t1.

[0087] In summary, this invention, based on the time-of-flight method, measures the atomic beam velocity by utilizing the time interval between the interaction of atoms with two discrete laser beams. This fills the gap in the empirical verification of atomic beam velocity, offering high measurement accuracy and reliability. Simultaneously, it advances research into the broadening of atomic transition spectral linewidths and transit times. The design principle of this application is clear, scientifically sound, and engineeringally feasible, possessing broad application prospects and representing a cutting-edge innovative design in the fields of atomic physics and optics.

[0088] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0089] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0090] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method of measuring the velocity of an atomic beam, characterized by, The method comprises: emitting a to-be-detected atomic beam, and making the atomic beam pass through a first resonance region (12) and a second resonance region (13) in sequence; exciting atoms in the second resonance region (13) in a ground state by using first resonance laser, and detecting the signal strength of fluorescence generated by spontaneous emission photons of the excited atoms in the second resonance region (13) falling back to the ground state, wherein the first resonance laser is a laser whose frequency is locked to a first resonance transition line of the atoms; after the detected signal strength of the fluorescence reaches a first stable amplitude value, exciting atoms in the first resonance region (12) in a ground state by using second resonance laser at a first time point, and determining the time point at which the signal strength of the fluorescence begins to weaken as a second time point, wherein the second resonance laser is a laser whose frequency is locked to a second resonance transition line of the atoms, and the excited state energy level lifetime of the second resonance transition line of the atoms is longer than that of the first resonance transition line; determining an atomic transit displacement according to the distance between the atomic excitation position in the second resonance region (13) and the atomic excitation position in the first resonance region (12), and determining an atomic transit time according to the interval between the first time point and the second time point; measuring the speed information of the atomic beam according to the atomic transit displacement and the atomic transit time.

2. The method of measuring the velocity of an atomic beam according to claim 1, wherein, The method further comprises: obtaining a speed estimation value of the to-be-detected atomic beam, and obtaining a detection response delay generated before the signal strength of the fluorescence is detected; determining an upper limit value of the atomic transit displacement according to the excited state energy level lifetime of the second resonance transition line of the atoms and the speed estimation value; determining a lower limit value of the atomic transit displacement according to the detection response delay and the speed estimation value.

3. The method of measuring the velocity of an atomic beam according to claim 1, wherein, The method further comprises: obtaining a response delay time detected before the second resonance laser excites the atoms in the second resonance region (13) in a ground state; Then, the determination of the atomic transit time according to the interval between the first time point and the second time point comprises: taking the time obtained by deducting the response delay time from the first time point as an actual excitation time point of the second resonance laser exciting the atoms in the first resonance region in a ground state; determining the atomic transit time according to the interval between the actual excitation time point and the second time point.

4. The method of measuring the velocity of an atomic beam according to claim 1 or 3, wherein The second time point further comprises a third time point corresponding to a value of a predetermined percentage of the first stable amplitude value, and the third time point is later than the second time point.

5. A system for measuring the velocity of an atomic beam, characterized by The method comprises: an atomic beam providing device (10) for emitting a to-be-detected atomic beam, wherein the atomic beam providing device (10) is sequentially provided with a first resonance region (12) and a second resonance region (13) along the emission direction of the atomic beam; an optical device (20) for providing first resonance laser and second resonance laser; A main control device connected with the optical device (20) for controlling the first resonant laser to excite the atoms in the ground state in the second resonant action region (13) and detecting the signal intensity of the fluorescence generated by the spontaneous emission photons of the excited atoms in the second resonant action region (13) falling back to the ground state; After the signal intensity of the fluorescence detected by the main control device reaches a first stable amplitude value, the main control device controls the second resonant laser to excite the atoms in the ground state in the first resonant action region at a first time point; A frequency locking component connected between the optical device (20) and the main control device, and the main control device controls the frequency locking component to lock the frequency of the first resonant laser provided by the optical device (20) on the first resonant transition line of the atoms and lock the frequency of the second resonant laser on the second resonant transition line of the atoms.

6. The system for measuring the velocity of an atomic beam according to claim 5, wherein, The main control device comprises: A computer device (31) connected with the optical device (20) and the frequency locking component, the computer device (31) controls the first resonant laser to excite the atoms in the ground state in the second resonant action region, and controls the second resonant laser to excite the atoms in the ground state in the first resonant action region at a first time point, and the computer device (31) controls the frequency locking component to lock the frequency of the first resonant laser provided by the optical device (20) on the first resonant transition line of the atoms and lock the frequency of the second resonant laser on the second resonant transition line of the atoms; A signal detector installed in the second resonant action region (13) and connected with the computer device (31), and the computer device (31) controls the signal detector to detect the signal intensity of the fluorescence.

7. The system for measuring the velocity of an atomic beam according to claim 6, wherein, The frequency locking component comprises a frequency locker (50) and a wavemeter (40), and the optical device (20) comprises: A first optical module (21) for providing the second resonant laser; A second optical module (22) for providing the first resonant laser; Both the first optical module (21) and the second optical module (22) comprise a laser, a laser adjusting component, a fiber collimator, a mechanical switch and a mirror; The frequency locker (50) is connected between the laser and the computer device (31); The laser adjusting component is arranged in the direction of the laser emitted by the laser, and the laser adjusting component emits transmitted light and reflected light after adjusting the laser, the fiber collimator is arranged in the direction of the transmitted light emitted by the laser adjusting component, and the mechanical switch and the mirror are arranged in the direction of the reflected light emitted by the laser adjusting component in sequence; The mechanical switch is connected with the computer device (31) and is controlled to be opened by the computer device (31); The fiber collimator is connected with the wavemeter (40).

8. The system for measuring the velocity of an atomic beam according to claim 7, wherein, The laser adjusting component comprises a half-wave plate and a polarization beam splitter prism.

9. The system for measuring the velocity of an atomic beam of claim 6, wherein, The master control device further comprises a data acquisition module (32) connected between the computer device (31) and the signal detector, and the computer device (31) controls the data acquisition module (32) to acquire the fluorescent signal intensity detected by the signal detector.

10. The system for measuring the velocity of an atomic beam of claim 5, wherein, The first resonance area (12) and the second resonance area (13) of the atomic beam current providing device are both provided with a laser incidence window (14).

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