Optimization method and device of cold atom magneto-optical trap system, equipment and medium

Abstract

The invention provides an optimization method and device of a cold atom magneto-optical trap system, equipment and a medium, and effectively solves the problems that the operation and adjustment of the magneto-optical trap system are relatively high in difficulty, relatively large in size and relatively high in power consumption. The method comprises the following steps: respectively processing laser light generated by a laser to obtain re-pumping light and pumping light; mixing the re-pumping light and the pumping light to obtain cooling light, irradiating the cooling light on the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain an imprisoned cold atomic group; fusing the imprisoned cold atomic group and a preset background image to obtain a background image with the cold atomic group so as to obtain an original cold atomic group photo and a background image photo; and performing operation based on the background image photo and the original cold atom group photo to obtain an operation result, and completing optimization of the cold atom magneto-optical trap system based on the operation result.

Description

Technical Field

[0001] The present application relates to the technical field of cold atom grating magneto-optical traps, and in particular to an optimization method, device, equipment and medium for a cold atom magneto-optical trap system. Background Art

[0002] Patented devices have been developed using conventional grating magneto-optical trap systems such as Figure 1 As shown, 780nm pump light and 795nm re-pump light are used to lock the two beams of light at a specific frequency point through saturated absorption spectrum, and then the laser frequency is adjusted to the required frequency through an acousto-optic modulator. The two laser beams are injected into a one-to-three optical fiber through a coupling head, and cooperate with a three-dimensional anti-Helmholtz coil to achieve cooling and trapping of atoms in a vacuum chamber, thereby obtaining cold atoms, and then taking photos containing cold atoms through a CCD camera, and then using the photos containing cold atoms to obtain the number of cold atoms, achieving the effect of cooling atoms and determining the number of trapped atoms.

[0003] The main problems with traditional magneto-optical trap systems are: traditional magneto-optical trap systems obtain cold atoms through three-beam opposing lasers and a three-dimensional anti-Helmholtz coil. They have high overall complexity, high degrees of freedom, require many components, and the components used are large, which leads to the magneto-optical trap system being large in size and high in power consumption. In addition, the components fail to cooperate with on-chip devices, making the magneto-optical trap system difficult to operate. Manually adjusting the cold atoms trapped in the magneto-optical trap system requires consideration of personnel experience and has a high time cost. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide an optimization method, device, equipment and medium for a cold atom magneto-optical trap system. The optimization method, device, equipment and medium for a cold atom magneto-optical trap system effectively solve the problems of high difficulty in operation and adjustment, large size and high power consumption of the magneto-optical trap system.

[0005] In a first aspect, an embodiment of the present application provides an optimization method for a cold atom magneto-optical trap system, which is applicable to a cold atom magneto-optical trap system, wherein the cold atom magneto-optical trap system includes a nested anti-Helmholtz coil, a grating chip, a laser, and a CCD camera, and the method includes:

[0006] Obtaining pump light based on the laser light generated by the laser, so as to generate corresponding re-pump light based on the pump light;

[0007] Mixing the re-pumping light and the pumping light to obtain cooling light, irradiating the cooling light onto the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain trapped cold atomic clusters;

[0008] The trapped cold atomic clusters are integrated with a preset background image to obtain a background image with cold atomic clusters, and the background image with cold atomic clusters and the background image are photographed respectively based on a CCD camera to obtain an original cold atomic cluster photo and a background image photo; the background image photo and the original cold atomic cluster photo are photographed in different anti-magnetic fields;

[0009] An operation is performed based on the background image photo and the original cold atom group photo to obtain an operation result, so as to optimize the cold atom magneto-optical trap system based on the operation result.

[0010] In combination with the first aspect, the embodiment of the present application provides a first possible implementation of the first aspect, wherein the calculation is performed based on the background image photo and the original cold atom group photo to obtain a calculation result, and the optimization of the cold atom magneto-optical trap system is completed based on the calculation result, including:

[0011] Subtracting the background image from the original cold atom group image to obtain a calculation result;

[0012] The number of cold atoms in the cold atomic cluster is calculated from the calculation results based on the preset optimization model.

[0013] In combination with the first aspect, the embodiment of the present application provides a second possible implementation of the first aspect, wherein the calculating the number of cold atoms in the cold atomic cluster from the calculation results based on the preset optimization model includes:

[0014] Optimizing the fluorescence intensity in the calculation result based on the preset optimization model to obtain an optimization result;

[0015] The number of cold atoms in the cold atom cluster corresponding to the calculation result is determined based on the relationship between the fluorescence intensity and the number of cold atoms in the cold atom cluster.

[0016] In combination with the first aspect, the embodiment of the present application provides a third possible implementation of the first aspect, wherein the mixing of the re-pumping light and the pumping light to obtain cooling light, irradiating the cooling light onto the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain a trapped cold atomic group, including:

[0017] Preprocessing the cooling light to obtain preprocessed cooling light; the preprocessing includes changing the polarization state and the size of the light spot of the cooling light;

[0018] The pre-processed cooling light is processed based on the grating chip to obtain diffracted light, so that the nested anti-Helmholtz coil generates trapped cold atomic clusters based on the diffracted light and the pre-processed cooling light through its own magnetic field.

[0019] In combination with the first aspect, the embodiment of the present application provides a fourth possible implementation of the first aspect, wherein the nested anti-Helmholtz coil generates trapped cold atomic clusters based on diffracted light and pre-processed cooling light through its own magnetic field, including:

[0020] sending the acquired multiple radii, working currents and working point positions of the nested anti-Helmholtz coils to the magnetic field intensity model respectively;

[0021] The magnetic field strength model obtains the magnetic field strength of the nested anti-Helmholtz coil by integrating multiple radii, working currents and working point positions of the nested anti-Helmholtz coil, so as to generate trapped cold atomic clusters based on the magnetic field strength of the nested anti-Helmholtz coil and pre-processed cooling light.

[0022] In combination with the first aspect, the embodiment of the present application provides a fifth possible implementation of the first aspect, wherein the obtaining of pump light based on the laser light generated by the laser to generate corresponding re-pump light based on the pump light includes:

[0023] Extracting a second laser from the laser light generated by the laser, and obtaining a third laser light and a pump light based on the second laser light;

[0024] The third laser driving is modulated based on an acousto-optic modulator to obtain re-pumping light.

[0025] In combination with the first aspect, an embodiment of the present application provides a sixth possible implementation of the first aspect, wherein the nested anti-Helmholtz coil is obtained by nesting an outer coil of a reverse magnetic field provided by an on-chip anti-Helmholtz coil into an inner coil, and has multiple layers of magnetic fields with different current flows, wherein the on-chip anti-Helmholtz coil is a planar coil.

[0026] In a second aspect, an embodiment of the present application provides an optimization device for a cold atom magneto-optical trap system, wherein the cold atom magneto-optical trap system includes a nested anti-Helmholtz coil, a grating chip, a laser, and a CCD camera, and the device includes:

[0027] A generating module, configured to obtain pump light based on the laser light generated by the laser, so as to generate corresponding re-pump light based on the pump light;

[0028] An irradiation module, used for mixing the re-pumping light and the pumping light to obtain cooling light, irradiating the cooling light onto the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain trapped cold atomic clusters; the cold atomic clusters are trapped by the magnetic field of the nested anti-Helmholtz coils;

[0029] A fusion module is used to fuse the trapped cold atomic clusters and a pre-set background image to obtain a background image with cold atomic clusters, and to respectively shoot the background image with cold atomic clusters and the background image based on a CCD camera to obtain an original cold atomic cluster photo and a background image photo; the background image photo and the original cold atomic cluster photo are shot in different anti-magnetic fields;

[0030] The operation module is used to perform operation based on the background image photo and the original cold atom group photo to obtain an operation result, so as to optimize the cold atom magneto-optical trap system based on the operation result.

[0031] In a third aspect, an embodiment of the present application provides an electronic device, comprising: a processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor and the memory communicate through the bus, and when the machine-readable instructions are executed by the processor, any step of the optimization method for a cold atom magneto-optical trap system is performed.

[0032] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of any one of the methods for optimizing a cold atom magneto-optical trap system are executed.

[0033] An optimization method for a cold atom magneto-optical trap system provided in an embodiment of the present application, the cold atom magneto-optical trap system includes a nested anti-Helmholtz coil, a grating chip, a laser and a CCD camera. The method first obtains a first laser and a second laser respectively based on the laser generated by the laser, and processes the first laser and the second laser respectively to obtain detection light corresponding to the first laser and re-pumping light and pumping light corresponding to the second laser; secondly, the re-pumping light and the pumping light are mixed to obtain cooling light, and the cooling light is irradiated on the grating chip, and the nested anti-Helmholtz coil is used to obtain a trapped cold atom cluster; then, the trapped cold atom cluster and a pre-set background image are fused to obtain a background image with cold atom clusters, and the background image with cold atom clusters and the background image are respectively photographed based on the CCD camera to obtain an original cold atom cluster photo and a background image photo; the background image photo and the original cold atom cluster photo are taken in different anti-Helmholtz magnetic fields; finally, calculations are performed based on the background image photo and the original cold atom cluster photo to obtain calculation results, and the calculation results are obtained based on the calculations. As a result, the cold atom magneto-optical trap system is optimized. The nested anti-Helmholtz coils are used to effectively improve the coordination between the devices in the cold atom magneto-optical trap system. The method of setting only one laser reduces the difficulty of operating the magneto-optical trap system, reduces the problems of large size and high power consumption of the magneto-optical trap system, reduces the power consumption of the magneto-optical trap system, ensures the trapping effect of cold atoms, reduces the complexity of the operation of the cold atom magneto-optical trap system, ensures the use effect of the cold atom magneto-optical trap system, and calculates based on the background image photo and the original cold atom group photo to obtain the calculation result, thereby ensuring the accuracy of the magneto-optical trap system in obtaining the number of cold atoms, thereby avoiding the problem of decreased accuracy when the magneto-optical trap system obtains the number of cold atoms, and adjusting the cold atoms trapped in the magneto-optical trap system based on the optimization method described in the present application, avoiding the problem of high time cost caused by manual adjustment and the need to consider manual experience, thereby ensuring the effectiveness and accuracy of adjusting the cold atoms trapped in the magneto-optical trap system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 A schematic diagram of a grating magneto-optical trap device used in conventional grating magneto-optical trap technology is shown;

[0036] Figure 2A schematic flow chart of a first method for optimizing a cold atom magneto-optical trap system provided in an embodiment of the present application is shown;

[0037] Figure 3 A schematic diagram of the structure of a cold atom magneto-optical trap system provided in an embodiment of the present application is shown;

[0038] Figure 4 A schematic diagram showing a theoretical model of a nested anti-Helmholtz coil provided in an embodiment of the present application is shown;

[0039] Figure 5 The cold atom cluster image acquired by the CCD camera provided in the embodiment of the present application and the schematic diagram of the cold atom detection timing are shown;

[0040] Figure 6 A schematic diagram showing a comparison between the method provided in the embodiment of the present application and the manual optimization method;

[0041] Figure 7 A schematic diagram showing temperature comparison between the optimization method provided in the embodiment of the present application and the manual optimization method is shown;

[0042] Figure 8 A schematic diagram showing the optimization of the cold atom magneto-optical trap system provided in an embodiment of the present application is shown;

[0043] Fig. 9 A stability comparison diagram of the cold atom magneto-optical trap system provided in an embodiment of the present application after optimization and in a free state is shown;

[0044] Fig.10 A schematic structural diagram of a first cold atom magneto-optical trap system optimization device provided in an embodiment of the present application is shown;

[0045] Fig.11 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application is shown.

[0046] Figure 3 Description of the accompanying figures:

[0047] 1- saturated absorption frequency stabilization system; 2- polarization beam splitter; 3- 780nm semiconductor laser;

[0048] 4-Acousto-optic modulator; 5-Electro-optic modulator; 6-Fiber collimator; 7-Quarter glass slide;

[0049] 8-convex lens; 9-fiber coupler; 10-single-mode polarization-maintaining fiber; 11-reflector;

[0050] 12-grating chip; 13-cold atomic group; 14-three-axis electric displacement platform;

[0051] 15- vacuum chamber; 16- CCD camera; 17- nested anti-Helmholtz coil. DETAILED DESCRIPTION

[0052] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of explanation and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn in real proportion. The flowchart used in this application shows the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowchart can be implemented out of sequence, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art can add one or more other operations to the flowchart under the guidance of the content of the present application, or remove one or more operations from the flowchart.

[0053] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0054] It should be noted that the term "comprising" will be used in the embodiments of the present application to indicate the existence of the features declared thereafter, but does not exclude the addition of other features.

[0055] The main problems with traditional magneto-optical trap systems are: traditional magneto-optical trap systems obtain cold atoms through three-beam opposing lasers and a three-dimensional anti-Helmholtz coil. They have high overall complexity, high degrees of freedom, require many components, and the components used are large, which leads to the magneto-optical trap system being large in size and high in power consumption. In addition, the components fail to cooperate with on-chip devices, making the magneto-optical trap system difficult to operate. Manually adjusting the cold atoms trapped in the magneto-optical trap system requires consideration of personnel experience and has a high time cost.

[0056] Based on this, the embodiments of the present application provide an optimization method, device, equipment and medium for a cold atom magneto-optical trap system, which is described below through embodiments.

[0057] To facilitate understanding of this embodiment, firstly, a method for optimizing a cold atom magneto-optical trap system disclosed in the embodiment of this application is described in detail. Figure 2The flowchart of a method for optimizing a cold atom magneto-optical trap system is shown. The present application provides a method for optimizing a cold atom magneto-optical trap system, wherein the cold atom magneto-optical trap system includes a nested anti-Helmholtz coil, a grating chip, a laser and a CCD camera. The method includes:

[0058] S101, obtaining pump light based on the laser light generated by the laser, so as to generate corresponding re-pump light based on the pump light;

[0059] S102, mixing the re-pumping light and the pumping light to obtain cooling light, irradiating the cooling light onto the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain trapped cold atomic clusters;

[0060] S103, fusing the trapped cold atomic clusters and a pre-set background image to obtain a background image with cold atomic clusters, and photographing the background image with cold atomic clusters and the background image respectively based on a CCD camera to obtain an original cold atomic cluster photo and a background image photo; the background image photo and the original cold atomic cluster photo are photographed in different anti-magnetic fields;

[0061] S104, performing calculations based on the background image photo and the original cold atom group photo to obtain calculation results, and completing the optimization of the cold atom magneto-optical trap system based on the calculation results.

[0062] The cold atom magneto-optical trap system applicable to this application is as follows Figure 3 As shown, the traditional grating magneto-optical trap technology is improved. The traditional cold atom cooling optical path uses 780nm laser as pump light and 795nm laser as re-pump light, that is, two lasers are used to complete the cooling and trapping of cold atoms. The present application uses only one laser as the light source, and the laser is a 780nm laser. The re-pump light required for cooling atoms is generated by the cooperation of EOM1 and AOM1. In this way, a single laser is used to complete the formation of cold atomic clusters, which effectively reduces the complexity of the cooling optical path, and a nested anti-Helmholtz coil is used to replace the traditional anti-Helmholtz coil, which reduces the power consumption of the system.

[0063] In step S101, the cold atom magneto-optical trap system in the present application uses a 780nm laser as a laser source to generate laser light and uses a saturated absorption frequency stabilization device SAS to lock the frequency of the laser output at 87 5 of the D2 line of Rb atoms 2 S 1 / 2 (F=2)→5 2 P 3 / 2(F=1co 3) the peak point of the cross-absorption peak spectral line, and then the laser generated by the laser is split to obtain the first laser and the second laser respectively, wherein all the features of the first laser and the second laser are exactly the same. It can be considered that the laser is copied to obtain two lasers, namely the first laser and the second laser, to process the first laser and the second laser respectively, to obtain the detection light corresponding to the first laser and the re-pumping light and pumping light corresponding to the second laser, the detection light is used to measure the temperature and number of the cold atomic clusters, the re-pumping light and pumping light are used to obtain the cooling light for generating cold atoms, and there is a difference between the re-pumping light and the pumping light, and they are not the same substance.

[0064] In the specific implementation process of step S101, there is an embodiment in which: the step of obtaining pump light based on the laser light generated by the laser, and generating corresponding re-pump light based on the pump light, comprises:

[0065] S1011, extracting a second laser from the laser light generated by the laser, and obtaining a third laser light and a pump light based on the second laser light;

[0066] S1012: modulate the third laser drive based on an acousto-optic modulator to obtain re-pumping light.

[0067] In steps S1011-S1012, AOM1, AOM2, and AOM3 in the cold atom magneto-optical trap system are all the same type of acousto-optic modulators. The laser generated by the laser is processed by the acousto-optic modulator AOM2 to obtain a detection light for measuring the temperature and number of cold atomic clusters. The detection light is used for detection when taking photos with cold atomic clusters to facilitate viewing of the cold atomic clusters. The cold atom magneto-optical trap system uses the second laser generated by the laser as pump light. The pump light is frequency-shifted by AOM3 to negatively detune the frequency of the pump light to 87 5 of the D2 line of Rb atoms 2 S 1 / 2 (F=2)→5 2 P 3 / 2 (F=3) transition peak, the pump light is divided into two after frequency shifting by a polarization beam splitter, and the split beams are pump light and a third laser respectively, the third laser enters the acousto-optic modulator EOM1 through a reflector, and the acousto-optic modulator EOM1 is driven by a 6.58Ghz radio frequency signal to generate a resonance sideband, wherein the resonance sideband is the re-pump light, and the generated re-pump light is transmitted through a fiber coupling head and a single-mode polarization-maintaining fiber, and the frequency of the re-pump light is stabilized at 87 5 of the D2 line of Rb atoms 2 S 1 / 2 (F=1)→5 2 P 1 / 2 (F=2)).

[0068] In step S102, the cold atom magneto-optical trap system couples the pump light into the optical fiber coupling head at the same time based on the re-pumping light emitted through the collimating head, that is, at this time, the pump light and the re-pumping light are mixed to obtain cooling light, and the cooling light is emitted through the collimating head after being transmitted through the single-mode optical fiber. Based on the generated cooling light, cold atom clusters can be generated, so the cooling light is irradiated on the grating chip of the cold atom magneto-optical trap system. The parameter size of the grating chip is independently designed so as to better meet the requirements of the cold atom magneto-optical trap system and is more conducive to the generation of cooling light. After the cooling light irradiates the grating chip, it cooperates with the nested anti-Helmholtz coil to obtain trapped cold atom clusters; in this way, the optical components used in the cold atom magneto-optical trap system and the complexity of the cold atom magneto-optical trap system are effectively reduced, and the cold atom clusters are trapped by the magnetic field of the nested anti-Helmholtz coil; wherein the vacuum cavity provides capture 87 The vacuum environment required by Rb atoms is maintained by an ion pump, and the vacuum degree of the vacuum chamber can be maintained at 10 -9 Pa level.

[0069] During the implementation of step S102, there is an implementation separation: the nested anti-Helmholtz coil is obtained by nesting an outer coil of a reverse magnetic field provided by an on-chip anti-Helmholtz coil into an inner coil, and has multiple layers of magnetic fields with different current flows, wherein the on-chip anti-Helmholtz coil is a planar coil.

[0070] In the grating magneto-optical trap technology, the traditional anti-Helmholtz coil structure is two coils at a certain distance that generate a magnetic field with a central intensity of zero and a gradient of about 10Gs / cm. However, the three-dimensional anti-Helmholtz structure greatly affects the further miniaturization of the grating magneto-optical trap. Although researchers have designed two coils into the same plane by compression, which greatly reduces the volume and power consumption of the anti-Helmholtz coil, the current power consumption still cannot meet the low power consumption requirements of the grating magneto-optical trap. The nested anti-Helmholtz coil used in the present application is a nested on-chip anti-Helmholtz coil to reduce system power consumption. The nested anti-Helmholtz coil described in the present application is different from the planar coil and the traditional three-dimensional anti-Helmholtz coil. It is not obtained by nesting the coils of the traditional three-dimensional anti-Helmholtz coil. It is based on the on-chip anti-Helmholtz coil, wherein the on-chip anti-Helmholtz coil is a planar coil, and the inner coil and the outer coil in the on-chip anti-Helmholtz coil are nested to form a nested anti-Helmholtz coil, that is, this structure is to nest the outer coil of the on-chip anti-Helmholtz coil that provides a reverse magnetic field into the inner coil to form a three-layer magnetic field structure with different current flows. Such a design can reduce the required power consumption of the outer coil when providing the same magnetic field strength at the working point position, thereby reducing the power consumption of the cold atom magneto-optical trap system. The theoretical model of the nested anti-Helmholtz coil used in the present application is as follows Figure 4 As shown, after measurement, the actual power consumption of the nested anti-Hai coil is about 0.9W, and at the working point, it can generate a magnetic field strength of 0Gs and a magnetic field gradient of about 12Gs / cm. This structure effectively reduces the volume of the cold atom magneto-optical trap system while also effectively reducing the power consumption of the cold atom magneto-optical trap system.

[0071] In the implementation process of step S102, there is an implementation method of: mixing the re-pumping light and the pumping light to obtain cooling light, irradiating the cooling light on the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain trapped cold atomic groups, including:

[0072] S1021, preprocessing the cooling light to obtain preprocessed cooling light; the preprocessing includes changing the polarization state and the size of the light spot of the cooling light;

[0073] S1022, processing the pre-processed cooling light based on the grating chip to obtain diffracted light, so that the nested anti-Helmholtz coil generates trapped cold atomic clusters based on the diffracted light and the pre-processed cooling light through its own magnetic field.

[0074] In steps S1021-S1022, the cold atom magneto-optical trap system is based on the cooling light emitted by the collimating head, and the cooling light is pre-processed through a quarter-wave plate and a convex lens in sequence to obtain the pre-processed cooling light; the polarization state of the cooling light is changed by the quarter-wave plate, and the size of the light spot of the cooling light is changed by the convex lens; then the cooling light at this time is more suitable for generating cold atom clusters, and after the pre-processed cooling light is vertically irradiated on the grating chip, the diffracted light generated based on the diffraction principle of light is combined with the pre-processed cooling light. After the cooling light overlaps, that is, the direction of the diffracted light is at a vertical angle to the pre-treated cooling light, the nested anti-Helmholtz coil is used to prepare cold atomic clusters in a vacuum chamber, thereby obtaining cold atomic clusters. That is, the interaction between the laser and the atoms in the vacuum chamber is used to reduce the kinetic energy of the atoms, so that the atoms are cooled to a temperature close to absolute zero, which is a cold atomic cluster. The magnetic confinement effect of the nested anti-Helmholtz coil uses the confinement effect of the magnetic field on atoms such as rubidium atoms to confine the cold atomic clusters in the central area of ​​the magnetic field to form a stable trapped cold atomic cluster.

[0075] In the implementation process of step S1022, there is an embodiment in which the nested anti-Helmholtz coil generates trapped cold atomic clusters based on diffracted light and pre-processed cooling light through its own magnetic field, including:

[0076] S10221, sending the acquired multiple radii, working currents and working point positions of the nested anti-Helmholtz coils to the magnetic field intensity model respectively;

[0077] S10222. The magnetic field strength model obtains the magnetic field strength of the nested anti-Helmholtz coil by integrating multiple radii, working currents and working point positions of the nested anti-Helmholtz coil, so as to generate trapped cold atomic clusters based on the magnetic field strength of the nested anti-Helmholtz coil and the pre-processed cooling light.

[0078] In steps S10221-S10222, when the nested anti-Helmholtz coil traps the cold atomic clusters generated based on the diffracted light and the pre-processed cooling light through its own magnetic field, multiple radii, working currents and working point positions of the nested anti-Helmholtz coil are obtained and sent to the magnetic field strength model. The working current can be obtained through a comprehensive instrument or multiple sensors. The multiple radii of the nested anti-Helmholtz coil are pre-acquired and stored in the magnetic field strength model. The working point position of the nested anti-Helmholtz coil is obtained according to the actual operation of the nested anti-Helmholtz coil. The magnetic field strength model of the nested anti-Helmholtz coil includes magnetic field strength and magnetic field gradient, which are respectively expressed by formulas (1)-(2):

[0079]

[0080] Wherein, z0 is the working point position of the nested anti-Helmholtz coil on the chip, where the chip is the PCB board, I is the working current, R N are the different radii of the nested anti-Helmholtz coils, μ0 is the vacuum magnetic permeability μ0=4π×10 -7 N / A 2 , B z is the magnetic field strength, The most suitable magnetic field strength of the nested anti-Helmholtz coils can be obtained based on the formulas (1)-(2) for the magnetic field gradient, thereby trapping the generated cold atomic clusters.

[0081] In step S103, after obtaining the cold atomic clusters, the cold atom magneto-optical trap system fuses the trapped cold atomic clusters with a pre-set background image to obtain a background image with cold atomic clusters, wherein the background image is concise, has a moderate contrast, and does not interfere with the observation of the cold atomic clusters. The anti-Hai magnetic field in shooting the background image photo and the original cold atomic cluster photo is different, that is, there is no anti-Hai magnetic field when shooting the background image photo, while there is an anti-Hai magnetic field when shooting the original cold atomic cluster photo, thereby obtaining the background image with cold atomic clusters, and based on using a CCD camera to respectively shoot the background image with cold atomic clusters and the background image, the original cold atomic cluster photo and the background image photo are obtained, such as Figure 5 As shown, it is a cold atom cluster image acquired by a CCD camera and a schematic diagram of the cold atom detection timing, wherein the cooling light includes pumping light and re-pumping light.

[0082] The specific steps of shooting are: pre-adjust the focus, exposure time, white balance and other parameters of the CCD camera to obtain the best image quality, and use the CCD camera to shoot the current background image, then use the TTL timing to open the gradient magnetic field of the nested anti-Helmholtz coil in the cold atom magneto-optical trap system to achieve cooling and trapping of the atomic clusters, and the CCD camera is exposed along the rising edge triggered by external hardware to shoot the background image with the cold atomic clusters to complete the shooting.

[0083] In step S104, the cold atom magneto-optical trap system aligns the original cold atom cluster photo with the background image photo, ensures that the background image photo and the original cold atom cluster photo are accurately aligned in space, and performs calculations based on the background image photo and the original cold atom cluster photo to obtain calculation results, so as to optimize the cold atom magneto-optical trap system based on the calculation results, thereby improving the accuracy of the number of cold atoms in the cold atom cluster trapped by the cold atom magneto-optical trap system, thereby avoiding the existence of errors caused by the background image, and ensuring the accuracy of the number of cold atoms in the obtained cold atom cluster. In order to avoid the existence of other errors or noise in the calculation results, image filtering technology and image enhancement operations can also be used, such as Gaussian filtering, median filtering or bilateral filtering, and image enhancement operations such as contrast stretching or histogram equalization, so as to improve the visibility of cold atom clusters and thereby ensure the accuracy of the number of cold atoms in the cold atom clusters.

[0084] The optimization method described in this application and the manual optimization method with manual adjustment were implemented simultaneously with the same parameters. The result was that 8×10 6 The trapping of atoms is nearly four times that of the manually adjusted manual optimization method, such as Figure 6 As shown, the left picture shows the cold atomic group in the artificial adjustment mode, and the right picture shows the cold atomic group obtained by the method described in this application. At the same time, the temperature of the cold atomic group is further reduced, such as Figure 7 As shown, the method described in this application is more effective than the manual optimization method of manual adjustment.

[0085] In the specific implementation process of step S104, there is an embodiment in which: the calculation is performed based on the background image photo and the original cold atom group photo to obtain a calculation result, and the optimization of the cold atom magneto-optical trap system is completed based on the calculation result, including:

[0086] S1041, subtracting the background image from the original cold atom group image to obtain a calculation result;

[0087] S1042. Calculate the number of cold atoms in the cold atomic cluster from the calculation results based on a preset optimization model.

[0088] In steps S1041-S1042, the cold atom magneto-optical trap system performs a pixel-level subtraction operation on the background image photo and the original cold atom cluster photo, that is, for each pixel point, the value of the corresponding pixel in the background image photo is subtracted from the pixel value of the original cold atom cluster photo, thereby obtaining the difference between the pixel value of the original cold atom cluster photo and the value of the corresponding pixel in the background image photo, and the difference is the operation result. The operation result value is applied to the preset optimization model, and the preset optimization model calculates the operation result to calculate the number of cold atoms in the cold atom cluster. The preset optimization model is preset and is expressed by formula (3):

[0089]

[0090] Among them, C(X) is the cost of a given set of parameters, also known as the cost function, n is the number of times a set of parameters is repeated, xy is the rectangular area where the cold atomic cluster is located, and p ij is the brightness of the pixel, ε is a small random bias, and the larger the cost function value, the better the cold atom cooling effect and the more trapped atoms. That is, when the cost function value is obtained according to the preset optimization model, the number of cold atoms in the cold atom cluster is determined. The cold atoms trapped here are 87 The Rb atom may also be other atoms.

[0091] In the specific implementation process of step S1042, there is an embodiment in which: the number of cold atoms in the cold atomic cluster is calculated from the calculation results based on the preset optimization model, including:

[0092] S10421, optimizing the fluorescence intensity in the calculation result based on the preset optimization model to obtain an optimization result;

[0093] S10422. Determine the number of cold atoms in the cold atom cluster corresponding to the calculation result based on the relationship between the fluorescence intensity and the number of cold atoms in the cold atom cluster.

[0094] In steps S10421-S10422, the cold atom magneto-optical trap system controls the preset optimization model to process the calculation result to obtain an optimization result, wherein the pixel brightness level p in the preset optimization model is ijThat is, the brightness of the atoms sensed by the CCD camera when the cold atoms in the cold atom cluster emit light. Based on the sum of the brightness of the cold atoms in the cold atom cluster represented by the brightness of the pixel when the cold atoms are photographed by the CCD camera when emitting light, the number of cold atoms in the cold atom cluster can be determined. That is, the luminous brightness of the cold atom cluster is proportional to the number of cold atoms in the cold atom cluster, which can be understood as a linear function relationship. Therefore, the preset optimization model can be used to directly use the sum of the brightness of the atoms in the photo as the number of atoms for optimization to obtain the optimization result. The pixel brightness p in the preset optimization model ij When the set value is reached, which can be considered as the maximum value of the preset optimization model, the optimization of the preset optimization model is stopped, and the number of cold atoms in the cold atomic cluster at this time is determined.

[0095] When the cold atom magneto-optical trap system obtains the number of cold atoms in the cold atom group, it needs to be optimized. During the optimization process, the parameters that need to be optimized include physical parameters such as pump light power, frequency, and magnetic field gradient. In addition, some mechanical parameters need to be adjusted, such as the incident direction, incident position, and incident angle of the laser. There are seven adjustment parameters involved in this application, namely, pump light power and frequency, re-pump light power, nested anti-Helmholtz coil magnetic field gradient, and the position of the incident laser (X, Y, Z axis). In addition, when optimizing the parameter range, this application does not have an artificially set range, but directly uses the limit range of all devices as the optimization range, which can better reflect the optimization ability of the optimization method, wherein the optimization parameter name, range, and data before and after optimization are shown in Table 1.

[0096] Table 1 Optimization parameter names, adjustment ranges and final results.

[0097]

[0098] The cold atom magneto-optical trap system is usually used as the core device for cold atom preparation in precision measurement systems. Under ultra-high measurement accuracy, the stability of the cold atom magneto-optical trap system is particularly important. The present application adopts a stable method combining dual algorithms to stabilize the number of cold atoms trapped in the cold atom magneto-optical trap system within the acceptable range of the system. In the fluorescence intensity stabilization experiment, the purpose is not to obtain the maximum intensity, but to reach the set value (the fluorescence intensity set value in this application is set to: ref), so the system can be optimized to the maximum value logic according to the preset optimization model. The cost function value of this optimization is expressed by formula (4):

[0099]

[0100] In this program, the set value can be considered as the maximum value to be reached. In the above formula, when the set value is less than the current fluorescence intensity, the calculation result is a negative value, and when the set value is greater than the current fluorescence intensity, the calculation result is a positive value. The negative sign can be used to convert it into a negative value, which ensures that the algorithm optimizes the current fluorescence intensity to a larger value. The maximum value that can be optimized is the set fluorescence intensity.

[0101] In order to suppress the negative impact of environmental changes on the cold atom magneto-optical trap system, when the cold atom magneto-optical trap system performs cold atom group stability optimization, the optimized parameters include four variables: pump light detuning, pump light power, re-pump light power, and magnetic field gradient. Figure 8 As shown, when the fluorescence intensity of the atomic cluster exceeds ±8% of the set range, optimization algorithm 1 is used to optimize the detuning of the pump light, thereby reducing the fluctuation of the fluorescence intensity of the atomic cluster. When the fluorescence intensity fluctuation is reduced to within the range of ±1.5% to ±8% of the set value, optimization algorithm 2 reduces the fluctuation range of the fluorescence intensity of the atomic cluster to within ±1.5% of the set value by adjusting the four variables of pump light detuning, pump light power, re-pump light power, and magnetic field gradient. Within this range, the system does not perform any operations but only monitors. The above two optimization algorithms have independent data sets. When different optimization algorithms are enabled, only the corresponding data sets are called, analyzed, and updated. The instability of the system can be effectively reduced by using optimization algorithms 1 and 2. What is more efficient is that optimization algorithms 1 and 2 do not need to distinguish which factors cause the instability of the system (whether it is all factors that may cause stability, such as ambient temperature changes, mechanical vacuum, laser frequency drift, optical power jitter, etc.). The required stability can be adjusted only through the above method. As shown in FIG. Fig. 9 As shown in the figure, the curve in the upper part represents the slow drift state of the system obtained after a long period of testing when the system is in a free-running state; the lower part is the curve effect after the algorithm is stabilized.

[0102] Example 2

[0103] The present application also provides an optimization device for a cold atom magneto-optical trap system, such as Fig.10 The block diagram of an optimization device for a cold atom magneto-optical trap system is shown. The functions implemented by the optimization device for a cold atom magneto-optical trap system correspond to the steps of performing the optimization method for a cold atom magneto-optical trap system on a terminal device. The device can be understood as a component of a server including a processor. The cold atom magneto-optical trap system includes a nested anti-Helmholtz coil, a grating chip, a laser and a CCD camera. The device includes:

[0104] A generating module 1001, configured to obtain pump light based on the laser light generated by the laser, so as to generate corresponding re-pump light based on the pump light;

[0105] An irradiation module 1002 is used for mixing the re-pumping light and the pumping light to obtain cooling light, irradiating the cooling light onto the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain trapped cold atomic clusters;

[0106] A fusion module 1003 is used to fuse the trapped cold atomic clusters with a preset background image to obtain a background image with cold atomic clusters, and to respectively shoot the background image with cold atomic clusters and the background image based on a CCD camera to obtain an original cold atomic cluster photo and a background image photo; the background image photo and the original cold atomic cluster photo are shot in different anti-magnetic fields;

[0107] The operation module 1004 is used to perform operation based on the background image photo and the original cold atom group photo to obtain an operation result, so as to optimize the cold atom magneto-optical trap system based on the operation result.

[0108] In a feasible implementation, the computing module includes:

[0109] A subtraction module, used for subtracting the background image photo from the original cold atom group photo to obtain a calculation result;

[0110] The calculation module is used to calculate the number of cold atoms in the cold atomic cluster from the calculation results based on a preset optimization model.

[0111] In a feasible implementation manner, the operation module further includes:

[0112] An optimization module, used for optimizing the fluorescence intensity in the calculation result based on the preset optimization model to obtain an optimization result;

[0113] The determination module is used to determine the number of cold atoms in the cold atom cluster corresponding to the calculation result based on the relationship between the fluorescence intensity and the number of cold atoms in the cold atom cluster.

[0114] In a feasible implementation, the irradiation module includes:

[0115] A changing module is used to pre-process the cooling light to obtain pre-processed cooling light; the pre-processing includes changing the polarization state and the size of the light spot of the cooling light;

[0116] The trapping module is used to process the pre-processed cooling light based on the grating chip to obtain diffracted light, so that the nested anti-Helmholtz coil generates trapped cold atomic clusters based on the diffracted light and the pre-processed cooling light through its own magnetic field.

[0117] In a feasible implementation manner, the irradiation module further includes:

[0118] An acquisition module, used for sending the acquired multiple radii, working currents and working point positions of the nested anti-Helmholtz coils to a magnetic field intensity model respectively;

[0119] An integration module is used for the magnetic field strength model to obtain the magnetic field strength of the nested anti-Helmholtz coil by integrating multiple radii, working currents and working point positions of the nested anti-Helmholtz coil, so as to generate trapped cold atomic clusters based on the magnetic field strength of the nested anti-Helmholtz coil and the pre-processed cooling light.

[0120] In a feasible implementation manner, the processing module includes:

[0121] A generating module, used for extracting a second laser from the laser generated by the laser, and obtaining a third laser and a pumping light based on the second laser;

[0122] The driving module is used to modulate the third laser drive based on an acousto-optic modulator to obtain re-pumping light.

[0123] In a feasible implementation, the irradiation module further includes:

[0124] The nested anti-Helmholtz coil is obtained by nesting an outer coil of the reverse magnetic field provided by an on-chip anti-Helmholtz coil into an inner coil, and has multiple layers of magnetic fields with different current flows, wherein the on-chip anti-Helmholtz coil is a planar coil.

[0125] Example 3

[0126] The present application also provides an electronic device, such as Fig.10 As shown, it includes: a processor 1101, a memory 1102 and a bus 1103, the memory 1102 stores machine-readable instructions executable by the processor 1101, when the electronic device is running, the processor 1101 communicates with the memory 1102 through the bus 1103, and when the machine-readable instructions are executed by the processor 1101, the steps of any one of the optimization methods for a cold atom magneto-optical trap system are performed.

[0127] Example 4

[0128] The present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of any one of the methods for optimizing a cold atom magneto-optical trap system are executed.

[0129] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the system and device described above can refer to the corresponding process in the method embodiment, and will not be repeated in this application. In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0130] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0131] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0132] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a platform server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard drives, ROM, RAM, magnetic disks, or optical disks.

[0133] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for optimizing a cold atom magneto-optical trap system, characterized in that: The cold atom magneto-optical trap system comprises a nested anti-Helmholtz coil, a grating chip, a laser and a CCD camera, and the method comprises: Obtaining pump light based on the laser light generated by the laser, so as to generate corresponding re-pump light based on the pump light; Mixing the re-pumping light and the pumping light to obtain cooling light, irradiating the cooling light onto the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain trapped cold atomic clusters; The trapped cold atomic clusters are integrated with a preset background image to obtain a background image with cold atomic clusters, and the background image with cold atomic clusters and the background image are photographed respectively based on a CCD camera to obtain an original cold atomic cluster photo and a background image photo; the background image photo and the original cold atomic cluster photo are photographed in different anti-magnetic fields; An operation is performed based on the background image photo and the original cold atom group photo to obtain an operation result, so as to optimize the cold atom magneto-optical trap system based on the operation result.

2. The method according to claim 1, characterized in that The step of performing a calculation based on the background image and the original cold atom group photo to obtain a calculation result, and optimizing the cold atom magneto-optical trap system based on the calculation result, includes: Subtracting the background image from the original cold atom group image to obtain a calculation result; The number of cold atoms in the cold atomic cluster is calculated from the calculation results based on the preset optimization model.

3. The method according to claim 2, characterized in that The step of calculating the number of cold atoms in the cold atomic cluster from the calculation results based on the preset optimization model includes: Optimizing the fluorescence intensity in the calculation result based on the preset optimization model to obtain an optimization result; The number of cold atoms in the cold atom cluster corresponding to the calculation result is determined based on the relationship between the fluorescence intensity and the number of cold atoms in the cold atom cluster.

4. The method according to claim 1, characterized in that: The mixing of the re-pumping light and the pumping light to obtain cooling light, irradiating the cooling light onto the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain trapped cold atomic groups, comprises: Preprocessing the cooling light to obtain preprocessed cooling light; the preprocessing includes changing the polarization state and the size of the light spot of the cooling light; The pre-processed cooling light is processed based on the grating chip to obtain diffracted light, so that the nested anti-Helmholtz coil generates trapped cold atomic clusters based on the diffracted light and the pre-processed cooling light through its own magnetic field.

5. The method according to claim 4, characterized in that The nested anti-Helmholtz coil generates trapped cold atomic groups based on diffracted light and pre-processed cooling light through its own magnetic field, including: sending the acquired multiple radii, working currents and working point positions of the nested anti-Helmholtz coils to the magnetic field intensity model respectively; The magnetic field strength model obtains the magnetic field strength of the nested anti-Helmholtz coil by integrating multiple radii, working currents and working point positions of the nested anti-Helmholtz coil, so as to generate trapped cold atomic clusters based on the magnetic field strength of the nested anti-Helmholtz coil and pre-processed cooling light.

6. The method according to claim 1, characterized in that The step of obtaining pump light based on the laser light generated by the laser, and generating corresponding re-pump light based on the pump light, comprises: Extracting a second laser from the laser light generated by the laser, and obtaining a third laser light and a pump light based on the second laser light; The third laser driving is modulated based on an acousto-optic modulator to obtain re-pumping light.

7. The method according to claim 1, characterized in that The nested anti-Helmholtz coil is obtained by nesting an outer coil of the reverse magnetic field provided by an on-chip anti-Helmholtz coil into an inner coil, and has multiple layers of magnetic fields with different current flows, wherein the on-chip anti-Helmholtz coil is a planar coil.

8. An optimization device for a cold atom magneto-optical trap system, characterized in that: The cold atom magneto-optical trap system comprises a nested anti-Helmholtz coil, a grating chip, a laser and a CCD camera, and the device comprises: A generating module, configured to obtain pump light based on the laser light generated by the laser, so as to generate corresponding re-pump light based on the pump light; An irradiation module, used for mixing the re-pumping light and the pumping light to obtain cooling light, irradiating the cooling light onto the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain trapped cold atomic clusters; A fusion module is used to fuse the trapped cold atomic clusters and a pre-set background image to obtain a background image with cold atomic clusters, and to respectively shoot the background image with cold atomic clusters and the background image based on a CCD camera to obtain an original cold atomic cluster photo and a background image photo; the background image photo and the original cold atomic cluster photo are shot in different anti-magnetic fields; The operation module is used to perform operation based on the background image photo and the original cold atom group photo to obtain an operation result, so as to optimize the cold atom magneto-optical trap system based on the operation result.

9. An electronic device, characterized in that: include: A processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor and the memory communicate via the bus, and when the machine-readable instructions are executed by the processor, the steps of the optimization method for the cold atom magneto-optical trap system as described in any one of claims 1 to 7 are performed.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which, when executed by a processor, executes the steps of the optimization method for the cold atom magneto-optical trap system as described in any one of claims 1 to 7.

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