An optimization method, device, equipment and medium of a cold atom magneto-optical trap system

Abstract

The application provides an optimization method, device and equipment of a cold atom magneto-optical trap system and a medium, effectively solving the problems of high difficulty in operation and adjustment, large volume and high power consumption of the magneto-optical trap system. The method comprises: processing laser generated by the laser respectively to obtain re-pumping light and pumping light; mixing the re-pumping light and the pumping light to obtain cooling light, and irradiating the cooling light on the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain a trapped cold atom group; fusing the trapped cold atom group and a pre-set background image to obtain a background image with a cold atom group, so as to obtain an original cold atom group photo and a background image photo; performing operation based on the background image photo and the original cold atom group photo to obtain an operation result, so as to complete optimization of the cold atom magneto-optical trap system based on the operation result.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of cold atom optical lattice magnetic optical traps, in particular to a cold atom magnetic optical trap system optimization method, device, equipment and medium. BACKGROUND

[0002] The existing patent device adopts a traditional optical lattice magnetic optical trap system as shown in the figure, uses 780nm pump light and 795nm repump light, locks the two beams of light at a specific frequency point through a saturated absorption spectrum, adjusts the laser frequency to the required frequency through an acousto-optic modulator, injects the two beams of light into a 1:3 optical fiber through a coupling head, cooperates with a three-dimensional anti-Helmholtz coil, realizes the cooling and trapping of atoms in a vacuum chamber, thereby obtaining cold atoms, and then photographs a picture containing the cold atoms through a CCD camera, and then obtains the number of cold atoms by using the picture containing the cold atoms, thereby realizing the effects of cooling atoms and determining the number of trapped atoms. Figure 1 The existing problems of the traditional magnetic optical trap system mainly include the following aspects: the traditional magnetic optical trap system obtains cold atoms through three beams of counter-shooting laser and a three-dimensional anti-Helmholtz coil, has high overall complexity, high degree of freedom, needs more components, and uses relatively large components, thereby causing the problems of a large volume and high power consumption of the magnetic optical trap system, and the components cannot cooperate with on-chip devices, thereby causing the magnetic optical trap system to be difficult to operate; and the phenomenon that the personnel experience needs to be considered when artificially adjusting the cold atoms trapped by the magnetic optical trap system and the time cost is high.

[0003] SUMMARY In view of this, the purpose of the application is to provide a cold atom magnetic optical trap system optimization method, device, equipment and medium, which effectively solves the problems of high difficulty in operation and adjustment, large volume and high power consumption of the magnetic optical trap system.

[0004] In the first aspect, the embodiments of the application provide a cold atom magnetic optical trap system optimization method, which is suitable for a cold atom magnetic optical trap system, the cold atom magnetic optical trap system includes a nested anti-Helmholtz coil, an optical lattice chip, a laser and a CCD camera, and the method includes the following steps:

[0005] Obtaining pump light based on the laser generated by the laser, and generating corresponding repump light based on the pump light;

[0006] Mixing the repump light and the pump light to obtain cooling light, irradiating the cooling light on the optical lattice chip, and cooperating with the nested anti-Helmholtz coil to obtain a group of trapped cold atoms;

[0007]

[0008] ​fuse the trapped cold atom group and the preset background image to obtain a background image with the cold atom group, and based on the CCD camera, the background image with the cold atom group and the background image are respectively shot to obtain a raw cold atom group photo and a background image photo; the background image photo and the raw cold atom group photo are different in the shot anti-Helmholtz field;

[0009] perform operation based on the background image photo and the raw cold atom group photo to obtain an operation result, and based on the operation result, optimization of the cold atom magneto-optical trap system is completed.

[0010] With reference to the first aspect, a second possible implementation manner of the first aspect is provided in the embodiments of the present application, and the operation based on the background image photo and the raw cold atom group photo to obtain an operation result, and based on the operation result, optimization of the cold atom magneto-optical trap system is completed, includes:

[0011] the background image photo and the raw cold atom group photo are subtracted to obtain the operation result;

[0012] based on a preset optimization model, the number of cold atoms in the cold atom group is calculated from the operation result.

[0013] With reference to the first aspect, a second possible implementation manner of the first aspect is provided in the embodiments of the present application, and the operation based on the background image photo and the raw cold atom group photo to obtain an operation result, and based on the operation result, optimization of the cold atom magneto-optical trap system is completed, includes:

[0014] based on the preset optimization model, the fluorescence intensity in the operation result is optimized to obtain an optimization result;

[0015] based on the relationship between the fluorescence intensity and the number of cold atoms in the cold atom group, the number of cold atoms in the cold atom group corresponding to the operation result is determined.

[0016] With reference to the first aspect, a third possible implementation manner of the first aspect is provided in the embodiments of the present application, and the mixing of the repumping light and the pumping light to obtain cooling light, and the irradiation of the cooling light on the grating chip, and the cooperation of the nested anti-Helmholtz coil to obtain the trapped cold atom group, includes:

[0017] the cooling light is pretreated to obtain pretreated cooling light; the pretreatment includes changing the polarization state of the cooling light and the size of the light spot;

[0018] based on the grating chip, the pretreated cooling light is processed to obtain diffracted light, so that the nested anti-Helmholtz coil generates the trapped cold atom group based on the diffracted light and the pretreated cooling light through the magnetic field of the nested anti-Helmholtz coil.

[0019] With reference to the first aspect, embodiments of the present application provide a fourth possible implementation manner of the first aspect, wherein the nested anti-Helmholtz coil generates the trapped cold atom group based on the diffraction light and the pre-processed cooling light through a magnetic field of the nested anti-Helmholtz coil, and the nested anti-Helmholtz coil comprises:

[0020] The obtained multiple radii, working currents and working point positions of the nested anti-Helmholtz coil are respectively sent to a magnetic field intensity model;

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

[0022] With reference to the first aspect, embodiments of the present application provide a fifth possible implementation manner of the first aspect, wherein the laser generated by the laser generator is used to obtain pump light, and the corresponding re-pump light is generated based on the pump light, and the method comprises the following steps:

[0023] Second laser is extracted from the laser generated by the laser generator, and third laser and pump light are obtained based on the second laser;

[0024] The third laser is modulated by an acousto-optic modulator to obtain re-pump light.

[0025] With reference to the first aspect, embodiments of the present application provide a sixth possible implementation manner of the first aspect, wherein the nested anti-Helmholtz coil is obtained by nesting an outer coil of a reverse magnetic field provided by a chip-on-reverse-Helmholtz coil into an inner coil, and the nested anti-Helmholtz coil has multiple layers of magnetic fields with different current directions, and the chip-on-reverse-Helmholtz coil is a planar coil.

[0026] In a second aspect, embodiments of the present application provide an optimization device of a cold atom magneto-optical trap system, the cold atom magneto-optical trap system comprising a nested anti-Helmholtz coil, a grating chip, a laser generator and a CCD camera, and the device comprises:

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

[0028] An irradiating module is configured to mix the re-pump light and the pump light to obtain cooling light, irradiate the cooling light on the grating chip, and obtain a trapped cold atom group in cooperation with the nested anti-Helmholtz coil; the cold atom group is trapped by a magnetic field of the nested anti-Helmholtz coil;

[0029] The fusion module is configured to fuse the trapped cold atom group and a preset background image to obtain a background image with the cold atom group, and to capture the background image with the cold atom group and the background image based on a CCD camera to obtain a cold atom group photo and a background photo; the background photo and the cold atom group photo are captured in different anti-Helmholtz magnetic fields.

[0030] The operation module is configured to perform operation based on the background photo and the cold atom group photo to obtain an operation result, and to complete optimization of 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, which comprises a processor, a memory and a bus, the memory stores machine readable instructions executable by the processor, when the electronic device is running, the processor and the memory communicate through the bus, and the machine readable instructions are executed by the processor to perform the steps of the optimization method of the cold atom magneto-optical trap system.

[0032] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, which stores a computer program, when the computer program is run by a processor, the steps of the optimization method of the cold atom magneto-optical trap system are executed.

[0033] The embodiment of the present application provides an optimization method of a cold atom magnetic optical trap system, the cold atom magnetic optical trap system comprises a nested anti-Helmholtz coil, a grating chip, a laser and a CCD camera, the method comprises the following steps: firstly, first laser and second laser are obtained based on the laser generated by the laser, the first laser and the second laser are processed respectively, detection light corresponding to the first laser and re-pumping light and pumping light corresponding to the second laser are obtained; secondly, the re-pumping light and the pumping light are mixed to obtain cooling light, the cooling light is irradiated on the grating chip, and the nested anti-Helmholtz coil is used to obtain a trapped cold atom group; then, the trapped cold atom group and a pre-set background image are fused to obtain a background image with the cold atom group, the background image with the cold atom group and the background image are photographed based on the CCD camera respectively, and an original cold atom group photo and a background image photo are obtained; the background image photo and the original cold atom group photo are different in a photographed anti-Helmholtz magnetic field; finally, operation is performed based on the background image photo and the original cold atom group photo, an operation result is obtained, the optimization of the cold atom magnetic optical trap system is completed based on the operation result, the nested anti-Helmholtz coil is used to effectively improve the cooperation degree between devices in the cold atom magnetic optical trap system, the method of setting only one laser reduces the difficulty of the magnetic optical trap system in operation, reduces the problems of large volume and high power consumption of the magnetic optical trap system, reduces the power consumption of the magnetic optical trap system, guarantees the trapping effect of the cold atom, reduces the complexity of the cold atom magnetic optical trap system in operation, guarantees the use effect of the cold atom magnetic optical trap system, the operation based on the background image photo and the original cold atom group photo is performed to obtain the operation result, thereby guaranteeing the accuracy of the number of cold atoms obtained by the magnetic optical trap system, and the problem of the accuracy of the number of cold atoms obtained by the magnetic optical trap system is avoided, the optimization method is used to adjust the cold atom trapped by the magnetic optical trap system, the problems of high time cost and the need to consider human experience in manual adjustment are avoided, and the effectiveness and accuracy of the adjustment of the cold atom trapped by the magnetic optical trap system are guaranteed. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0035] Figure 1 A schematic diagram of a grating magnetic optical trap device used in a traditional grating magnetic optical trap technology is shown.

[0036] Figure 2A flowchart of an optimization method of a first cold atom magneto-optical trap system is shown.

[0037] Figure 3 A structure diagram of a cold atom magneto-optical trap system is shown.

[0038] Figure 4 A schematic diagram of a theoretical model of a nested anti-Helmholtz coil is shown.

[0039] Figure 5 A cold atom group image obtained by a CCD camera and a cold atom detection timing diagram are shown.

[0040] Figure 6 A comparison diagram of the method and a manual optimization method is shown.

[0041] Figure 7 A temperature comparison diagram of the optimization method and a manual optimization method is shown.

[0042] Figure 8 An optimization diagram of a cold atom magneto-optical trap system is shown.

[0043] Figure 9 A stability comparison diagram of a cold atom magneto-optical trap system after optimization and a free state is shown.

[0044] Figure 10 A structure diagram of an optimization device of a first cold atom magneto-optical trap system is shown.

[0045] Figure 11 A structure diagram of an electronic device is shown.

[0046] Figure 3 Explanation of reference numerals in the accompanying drawings:

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

[0048] 4-acoustic-optic modulator; 5-electro-optic modulator; 6-fiber collimator; 7-quarter wave plate;

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

[0050] 12-grating chip; 13-cold atom group; 14-three-axis electrically driven displacement stage;

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

[0052] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to 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 illustration 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 to scale. The flowcharts used in the present application show the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowcharts can be implemented in no order, and the steps without logical context relationship can be reversed in order or implemented simultaneously. In addition, one or more other operations can be added to the flowcharts or one or more operations can be removed from the flowcharts under the guidance of the content of the present application.

[0053] In addition, the described embodiments are only some of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different 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 claimed present application, but only represents 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 creative labor are within 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 presence of the features declared thereafter, but does not exclude the addition of other features.

[0055] The main problems of the traditional magneto-optical trap system are: the traditional magneto-optical trap system obtains cold atoms through three beams of counter-propagating laser and a three-dimensional anti-Helmholtz coil, which has high overall complexity, high degree of freedom, requires more components, and uses larger components, thereby causing the magneto-optical trap system to have a large volume and high power consumption, and the components cannot be matched with on-chip devices, causing the magneto-optical trap system to be difficult to operate; and the need to consider personnel experience and the high time cost when artificially adjusting the cold atoms trapped by the magneto-optical trap system.

[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 will be described below through embodiments.

[0057] In order to facilitate the understanding of the present embodiment, first, a cold atom magneto-optical trap system optimization method disclosed in the embodiments of the present application is introduced in detail. As shown in Figure 2The application provides an optimization method of a cold atom magneto-optical trap system. The cold atom magneto-optical trap system comprises a nested anti-Helmholtz coil, a grating chip, a laser and a CCD camera. The method comprises the following steps:

[0058] In S101, pump light is obtained based on the laser generated by the laser, and corresponding repump light is generated based on the pump light;

[0059] In S102, cooling light is obtained by mixing the repump light and the pump light, the cooling light is irradiated on the grating chip, and the nested anti-Helmholtz coil is used to obtain trapped cold atom groups;

[0060] In S103, the trapped cold atom groups and a preset background image are fused to obtain a background image with cold atom groups, the CCD camera is used to respectively shoot the background image with cold atom groups and the background image to obtain an original cold atom group photo and a background image photo, and the background image photo and the original cold atom group photo are shot in different anti-Helmholtz magnetic fields.

[0061] In S104, operation is performed based on the background image photo and the original cold atom group photo to obtain an operation result, and optimization of the cold atom magneto-optical trap system is completed based on the operation result.

[0062] The cold atom magneto-optical trap system to which the application is applied is shown in Figure 3 The traditional grating magneto-optical trap technology is improved. The traditional cold atom cooling light path uses 780 nm laser as pump light and 795 nm laser as repump light, that is, two kinds of lasers are used to complete the cooling and trapping of cold atoms. The application only uses one laser as a light source, and the laser is a 780 nm laser. The repump light required for cooling atoms is generated by cooperation of an EOM1 and an AOM1. In this way, the formation of a cold atom group is realized by using a single laser, the complexity of the cooling light path is effectively reduced, and a nested anti-Helmholtz coil is used to replace the traditional anti-Helmholtz coil, thereby reducing the power consumption of the system.

[0063] In step S101, the cold atom magneto-optical trap system in the application uses a 780 nm laser as a laser source to generate laser based on a saturated absorption frequency stabilization device SAS, and the frequency of laser output is locked at 87 5 2 S 1 / 2 (F=2)→5 2 P 3 / 2(F=1co 3) cross-absorption peak spectrum line peak point, and then by the laser produced by the laser beam splitting to obtain the first laser and the second laser, wherein the first laser and the second laser are all the same characteristics, can be considered as the laser is copied to get two laser, respectively, the first laser and the second laser, to process the first laser and the second laser, respectively, to obtain the first laser corresponding to the probe light and the second laser corresponding to the re-pumping light and the pumping light, the probe light is used to measure the temperature and quantity of cold atom group, the re-pumping light and the pumping light are used to obtain the cooling light for generating cold atoms, the re-pumping light and the pumping light are different, and are not the same substance.

[0064] In the implementation process of step S101, there is an embodiment that: the pumping light is obtained based on the laser generated by the laser, and the corresponding re-pumping light is generated based on the pumping light, comprising:

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

[0066] S1012, modulating the third laser driven by the acousto-optic modulator to obtain the re-pumping light.

[0067] In steps S1011-S1012, the AOM1, AOM2 and AOM3 in the cold atom magnetic optical trap system are the same acousto-optic modulator. The laser generated by the laser is processed by the acousto-optic modulator AOM2 to obtain the probe light for measuring the temperature and quantity of cold atom group. The probe light is used to detect the photo with cold atom group to facilitate the observation of cold atom group. The second laser generated by the laser is used as the pumping light. The pumping light is frequency shifted by AOM3. The frequency of the pumping light is negatively detuned to 87 5 2 S 1 / 2 (F=2)→5 2 P 3 / 2 (F=3) transition peak, after frequency shift, the pumping light is divided into two by the polarized beam splitter, and the pumping light and the third laser are obtained after the beam splitting. The third laser enters the acousto-optic modulator EOM1 through the mirror. The acousto-optic modulator EOM1 generates resonance sideband under the driving of 6.58Ghz radio frequency signal. The resonance sideband is the re-pumping light. The generated re-pumping light is transmitted through the optical fiber coupling head and the single-mode polarization maintaining optical fiber. The frequency of the re-pumping light is stably at 87 5 2 S 1 / 2 (F=1)→5 2 P 1 / 2 (F=2)).

[0068] In step S102, the cold atom magneto-optical trap system will be based on the re-pumping light out of the collimation head after the pump light is coupled into the fiber coupling head at the same time, that is, the pump light and the re-pumping light are mixed to obtain cooling light at this time, the cooling light is transmitted through a single-mode optical fiber and then emitted through a collimation head, based on the generated cooling light, a cold atom group 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 to better meet the requirements of the cold atom magneto-optical trap system and be more conducive to generating cooling light, after the cooling light irradiates the grating chip, it cooperates with the nested anti-Helmholtz coil to obtain a trapped cold atom group; in this way, the optical components used by 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 group is trapped by the magnetic field of the nested anti-Helmholtz coil; wherein the vacuum cavity provides the vacuum environment required for capturing 87 Rb atoms, the vacuum degree of the vacuum cavity is maintained by an ion pump, and the vacuum degree can be maintained at 10 -9 Pa order of magnitude.

[0069] In the implementation process of step S102, there is an implementation: the nested anti-Helmholtz coil is the outer coil nested into the inner coil provided by the reverse magnetic field of the on-chip anti-Helmholtz coil, which has a magnetic field with multiple layers of different current directions, 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 with a certain distance to generate a magnetic field with a central strength of zero and a gradient of about 10 Gs / 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 through compression, greatly reducing the volume and power consumption of the anti-Helmholtz coil, the current power consumption still cannot meet the low-power requirement 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 traditional three-dimensional anti-Helmholtz coil. It is based on the on-chip anti-Helmholtz coil, which is a planar coil. The inner coil and the outer coil in the on-chip anti-Helmholtz coil are nested to form a nested anti-Helmholtz coil, i.e. the outer coil of the on-chip anti-Helmholtz coil provides a reverse magnetic field. The inner coil is nested to form a three-layer magnetic field structure with different current directions. Such design can reduce the required power consumption of the outer coil under the condition of 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 shown in Figure 4 The actual power consumption of the nested anti-Helmholtz coil is about 0.9 W, and the magnetic field strength at the working point position is 0 Gs, and the required magnetic field gradient is about 12 Gs / cm. This structure effectively reduces the volume of the cold atom magneto-optical trap system while 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: mixing the repumping light and the pump light to obtain cooling light, and irradiating the cooling light on the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain a trapped cold atom group, including:

[0072] S1021, pre-treat the cooling light to obtain pre-treated cooling light; the pre-treatment includes changing the polarization state and the size of the light spot of the cooling light;

[0073] S1022, process the pre-treated cooling light based on the grating chip to obtain diffracted light, so that the nested anti-Helmholtz coil generates a trapped cold atom group based on the diffracted light and the pre-treated cooling light through its own magnetic field.

[0074] In steps S1021-S1022, the cold atom magneto-optical trap system is based on the collimating head emitted cooling light, and the cooling light is sequentially pre-processed through a quarter-wave plate and a convex lens to obtain pre-processed cooling light; the polarization state of the cooling light is changed through the quarter-wave plate, and the size of the cooling light spot is changed through the convex lens; at this time, the cooling light is more suitable for generating a cold atom group; after the pre-processed cooling light is vertically irradiated on the grating chip, based on the diffraction principle of light, the diffraction light is generated; after the diffraction light and the pre-processed cooling light are overlapped, the direction of the diffraction light is at a right angle with the pre-processed cooling light at this time; and the nested anti-Helmholtz coil is used in the vacuum chamber to realize the preparation of the cold atom group, so as to obtain the cold atom group, that is, the vacuum chamber uses the interaction between laser and atom to reduce the kinetic energy of the atom, so that the atom is cooled to a temperature close to absolute zero, that is, the cold atom group; and the magnetic confinement effect of the nested anti-Helmholtz coil uses the constraint effect of the magnetic field on the atom such as rubidium atom to confine the cold atom group in the central region of the magnetic field, and forms a stable confined cold atom group.

[0075] In the implementation process of step S1022, there is an embodiment that the nested anti-Helmholtz coil generates a confined cold atom group based on the diffraction light and the pre-processed cooling light through its own magnetic field, which includes:

[0076] S10221, respectively, the obtained multiple radii, working current and working point position of the nested anti-Helmholtz coil are sent to the magnetic field strength model;

[0077] S10222, the magnetic field strength model obtains the magnetic field strength of the nested anti-Helmholtz coil by integrating the multiple radii, working current and working point position of the nested anti-Helmholtz coil, so as to generate a confined cold atom group based on the magnetic field strength of the nested anti-Helmholtz coil and the pre-processed cooling light.

[0078] In steps S1021-S1022, when the nested anti-Helmholtz coil confines the cold atom group generated based on the diffraction light and the pre-processed cooling light through its own magnetic field, the multiple radii, working current and working point position of the nested anti-Helmholtz coil are sent to the magnetic field strength model, the working current can be obtained by a comprehensive instrument or multiple sensors, the multiple radii of the nested anti-Helmholtz coil are pre-obtained and stored in the magnetic field strength model, and the working point position of the nested anti-Helmholtz coil is obtained according to the actual working 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 represented by formulas (1)-(2):

[0079]

[0080] wherein z0 is the working point position of the nested anti-Helmholtz coil on the board, I is the working current, R N is the different radius of the nested anti-Helmholtz coil, μ0 is the vacuum permeability μ0 = 4π × 10 -7 N / A 2 , B z is the magnetic field intensity, is the magnetic field gradient, so the most suitable magnetic field intensity of the nested anti-Helmholtz coil can be obtained based on the formula (1)-(2), so as to trap the generated cold atom group.

[0081] In step S103, the cold atom magneto-optical trap system fuses the trapped cold atom group and the pre-set background image after obtaining the cold atom group, to obtain a background image with the cold atom group, the background image being a simple, moderate contrast and non-interfering image for observing the cold atom group, the background image being photographed in a different anti-Helmholtz magnetic field from the original cold atom group, that is, the background image is photographed without the anti-Helmholtz magnetic field, while the original cold atom group is photographed with the anti-Helmholtz magnetic field, so as to obtain the background image with the cold atom group, and the original cold atom group and the background image are obtained by using the CCD camera to respectively photograph the background image with the cold atom group and the background image, as shown in Figure 5 the cold atom group image obtained by the CCD camera and the cold atom detection timing diagram.

[0082] The specific steps of photographing are as follows: the focus, exposure time, white balance and other parameters of the CCD camera are pre-adjusted to obtain the best image quality, and the current background image is photographed by using the CCD camera, then the TTL timing turns on the gradient magnetic field of the nested anti-Helmholtz coil in the cold atom magneto-optical trap system, to realize the cooling and trapping of the atom group, the CCD camera is triggered by the external hardware to rise and expose, to photograph the background image with the cold atom group, and the photographing is completed.

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

[0084] Based on the optimization method described in the present application and the manual optimization method of artificial adjustment, the same parameters are implemented at the same time, and the result is that the confinement of 8x10 6 atoms is successfully realized in 21 minutes, which is nearly four times that of the manual optimization method of artificial adjustment, as shown in the left figure of the cold atom group of the artificial adjustment mode and the right figure of the cold atom group obtained by the method described in the present application. At the same time, the temperature of the cold atom group is further reduced, as shown in the left figure of the cold atom group of the artificial adjustment mode and the right figure of the cold atom group obtained by the method described in the present application. That is, the method described in the present application is superior to the manual optimization method of artificial adjustment. Figure 6 Figure 7 The temperature of the cold atom group is further reduced, as shown in the left figure of the cold atom group of the artificial adjustment mode and the right figure of the cold atom group obtained by the method described in the present application. That is, the method described in the present application is superior to the manual optimization method of artificial adjustment.

[0085] In the specific implementation process of step S104, there is an embodiment that: the operation based on the background photo and the original cold atom group photo to obtain an operation result, and completing the optimization of the cold atom magneto-optical trap system based on the operation result, includes:

[0086] S1041, subtracting the background photo from the original cold atom group photo to obtain an operation result;

[0087] S1042, calculating the number of cold atoms in the cold atom group from the operation result based on a preset optimization model.

[0088] ​In steps S1041-S1042, the cold atom magneto-optical trap system obtains the difference between the pixel value of the original cold atom group picture and the value of the corresponding pixel in the background picture by performing pixel-level subtraction operation on the background picture and the original cold atom group picture, i.e., for each pixel, subtracting the value of the corresponding pixel in the background picture from the pixel value of the original cold atom group picture, so as to obtain the difference between the pixel value of the original cold atom group picture and the value of the corresponding pixel in the background picture, which is the operation result. The operation result is input into the preset optimization model, and the preset optimization model calculates the operation result, so as to calculate the number of cold atoms in the cold atom group. The preset optimization model is preconfigured, and is represented by formula (3):

[0089]

[0090] wherein C(X) is the cost overhead of a given set of parameters, also referred to as a cost function, n is the number of repeated execution of the set of parameters, xy is the rectangular region where the cold atom group is located, p is the brightness of the pixel, and ε is a small random bias. ij The greater the cost function value, the better the cooling effect of the cold atoms and the more the trapped atoms. When the cost function value is obtained according to the preset optimization model, the number of cold atoms in the cold atom group is determined. The cold atoms subjected to the trapped cooling are Rb atoms, and can also be other atoms. 87 Rb atoms, and can also be other atoms.

[0091] In the implementation process of step S1042, there is an embodiment that the number of cold atoms in the cold atom group is calculated from the operation result based on the preset optimization model, which includes:

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

[0093] S10422, determining the number of cold atoms in the cold atom group corresponding to the operation result based on the relationship between the fluorescence intensity and the number of cold atoms in the cold atom group.

[0094] In steps S1041-S1042, the cold atom magneto-optical trap system controls the preset optimization model to process the operation result, so as to obtain an optimization result, wherein the brightness p of the pixel in the preset optimization model is represented by formula (4): ijThe brightness of the atoms sensed by the CCD camera when taking a picture of the cold atoms in the cold atom group when the cold atoms emit light is the sum of the brightness of the atoms in the cold atom group when the cold atoms emit light and are captured by the CCD camera based on the brightness of the pixels, and the number of cold atoms in the cold atom group can be determined. The brightness of the cold atom group and the number of cold atoms in the cold atom group are in a proportional relationship, which can be understood as a linear relationship, so the sum of the brightness of the atoms in the picture can be directly used as the number of atoms to obtain the optimization result by the preset optimization model. The brightness of the pixels p in the preset optimization model ij When the set value is reached, which can be determined 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 atom group at this time is determined.

[0095] The cold atom magneto-optical trap system needs to be optimized to obtain the number of cold atoms in the cold atom group. In the optimization process, the parameters to be optimized include 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. The seven parameters involved in this application are pump light power and frequency, repump light power, nested anti-Helmholtz coil magnetic field gradient, and incident laser position (X, Y, Z axis). In addition, this application does not artificially set the range when optimizing the parameters, but directly uses the limit range of all devices as the optimization range, which better reflects the optimization ability of the optimization method. The optimization parameter name, range, and data before and after optimization are shown in Table 1.

[0096] Table 1 Optimization parameter name, adjustment range, and final result.

[0097]

[0098] The cold atom magneto-optical trap system is usually used as a core device for cold atom preparation in precision measurement systems. Under ultra-high measurement precision, the stability of the cold atom magneto-optical trap system is particularly important. This application uses a double algorithm combined stabilization method to stabilize the number of cold atoms trapped by the cold atom magneto-optical trap system within the acceptable range of the system. In the fluorescence intensity stability experiment, the purpose is not to obtain the maximum intensity, but to reach a set value (in this application, the fluorescence intensity set value is set to: ref). Therefore, according to the preset optimization model, the system can be optimized to the maximum value. The cost function value of this optimization is represented 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 negative; when the set value is greater than the current fluorescence intensity, the calculation result is positive, which can be converted to negative by the negative sign. In this way, the algorithm optimization can optimize the current fluorescence intensity to a larger value, and the maximum value that can be optimized is the set fluorescence intensity.

[0101] In order to inhibit the negative influence of environmental changes on the cold atom magneto-optical trap system, when the cold atom group stability optimization is performed on the cold atom magneto-optical trap system, the optimized parameters include the pump light detuning, the pump light power, the repump light power, and the magnetic field gradient. As shown in Figure 8 When the fluorescence intensity of the atomic group exceeds ±8% of the set range, the pump light detuning is optimized using the optimization algorithm 1, so as to reduce the fluctuation of the atomic group fluorescence intensity. When the fluorescence intensity fluctuation is reduced to the range of ±1.5% to ±8% of the set value, the optimization algorithm 2 reduces the atomic group fluorescence intensity fluctuation range to ±1.5% of the set value by adjusting the pump light detuning, the pump light power, the repump light power, and the magnetic field gradient. Within this range, the system does not perform any operation, but only performs monitoring. The above two optimization algorithms have independent data sets, and when different optimization algorithms are enabled, only the corresponding data set is called, analyzed and updated. Through the optimization algorithm 1 and the optimization algorithm 2, the instability of the system can be effectively reduced. A more efficient point is that through the optimization algorithm 1 and the optimization algorithm 2, it is not necessary to distinguish what factor causes the instability of the system (all factors that may cause instability, such as environmental temperature change, mechanical vacuum, laser frequency drift, and light power jitter), and the required stability can be adjusted through the above method. As shown in Figure 9 The upper half of the curve in the figure represents the slow drift state of the system in the free running state, and the lower half represents the curve effect after the algorithm is stabilized.

[0102] Embodiment 2

[0103] The application also provides an optimization device of a cold atom magneto-optical trap system, as shown in Figure 10 The block diagram of the optimization device of the cold atom magneto-optical trap system corresponds to the steps of the above-mentioned method of optimizing the cold atom magneto-optical trap system on the 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, an optical lattice chip, a laser, and a CCD camera. The device includes:

[0104] The generating module 1001 is configured to generate pump light based on the laser generated by the laser, and generate corresponding repump light based on the pump light.

[0105] Irradiation module 1002, for mixing the repumping light and the pumping light to obtain cooling light, and irradiating the cooling light on the grating chip, and cooperating with the nested anti-Helmholtz coil to obtain a trapped cold atom group;

[0106] Fusion module 1003, for fusing the trapped cold atom group and a pre-set background image to obtain a background image with a cold atom group, so as to capture the background image with a cold atom group and the background image based on the CCD camera respectively, to obtain a raw cold atom group photo and a background image photo; the background image photo and the raw cold atom group photo are different in the anti-Helmholtz field in shooting;

[0107] Operation module 1004, for performing operation based on the background image photo and the raw cold atom group photo to obtain an operation result, so as to complete optimization of the cold atom magneto-optical trap system based on the operation result.

[0108] In a possible implementation, the operation module comprises:

[0109] Subtraction module, for subtracting the background image photo from the raw cold atom group photo to obtain an operation result;

[0110] Calculation module, for calculating the number of cold atoms in the cold atom group from the operation result based on a pre-set optimization model.

[0111] In a possible implementation, the operation module further comprises:

[0112] Optimization module, for processing the fluorescence intensity in the operation result based on the pre-set optimization model to obtain an optimization result;

[0113] Determination module, for determining the number of cold atoms in the cold atom group corresponding to the operation result based on the relationship between the fluorescence intensity and the number of cold atoms in the cold atom group.

[0114] In a possible implementation, the irradiation module comprises:

[0115] Change module, for pre-processing the cooling light to obtain pre-processed cooling light; the pre-processing comprises changing the polarization state of the cooling light and the size of the light spot;

[0116] Trapping module, for processing the pre-processed cooling light based on the grating chip to obtain diffracted light, so that the nested anti-Helmholtz coil generates a trapped cold atom group based on the diffracted light and the pre-processed cooling light through the magnetic field of the nested anti-Helmholtz coil.

[0117] In a possible implementation, the irradiation module further comprises:

[0118] The acquisition module is configured to send the acquired radius, working current and working point position of the nested anti-Helmholtz coil to the magnetic field strength model respectively.

[0119] The integration module is configured to obtain the magnetic field strength of the nested anti-Helmholtz coil by integrating the radius, working current and working point position of the nested anti-Helmholtz coil, so as to generate the trapped cold atom group based on the magnetic field strength of the nested anti-Helmholtz coil and the preprocessed cooling light.

[0120] In an embodiment, the processing module comprises:

[0121] The generating module is configured to extract a second laser from the laser generated by the laser generator, and obtain a third laser and pump light based on the second laser.

[0122] The driving module is configured to drive the third laser to obtain the repump light based on the acousto-optic modulator.

[0123] In an embodiment, the irradiating module further comprises:

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

[0125] Embodiment 3

[0126] The embodiment of the present application further provides an electronic device, such as Figure 10 As shown in the figure, the electronic device comprises 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 and the memory 1102 communicate through the bus 1103, and the machine readable instructions are executed by the processor 1101 to perform the steps of the optimization method of the cold atom magneto-optical trap system according to any one of the embodiments.

[0127] Embodiment 4

[0128] The present application further provides a computer readable storage medium, the computer readable storage medium stores a computer program, and the computer program is executed by a processor to perform the steps of the optimization method of the cold atom magneto-optical trap system according to any one of the embodiments.

[0129] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working process of the system and the device described above can refer to the corresponding process in the method embodiment, and will not be repeated in the present application. In the several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented by other means. The above-described device embodiments are only schematic, for example, the division of the modules is only a logical function division, and the actual implementation can have another division manner, for example, a plurality of modules or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the shown or discussed mutual elements can be indirect coupling or communication connection through some communication interface, device or module, which can be electrical, mechanical or other forms.

[0130] The modules described as separate components can or can not be physically separated, and the components shown as modules can or can not be physical units, i.e. can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

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

[0132] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a non-volatile computer readable storage medium executable by a processor. Based on this understanding, the technical solutions of the present application essentially or the parts of the prior art that make contributions or parts of the technical solutions can be embodied in the form of software products, which are stored in a storage medium and include a plurality of instructions for causing a computer device (which can be a personal computer, a platform server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes: U disk, mobile hard disk, ROM, RAM, magnetic disk or optical disk and various program code storage media.

[0133] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of optimizing a cold atom magneto-optical trap system, comprising: 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 the following steps: Pump light is obtained based on the laser generated by the laser, and corresponding re-pump light is generated based on the pump light; The re-pump light and the pump 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 trapped cold atom groups; Raw cold atom group photos and background photo photos are respectively taken based on the CCD camera; the background photo photos and the raw cold atom group photos are different in the reverse magnetic field during shooting; the raw cold atom group photos are obtained by fusing the trapped cold atom groups and the pre-set background photos to obtain background photos with cold atom groups; the background photo photos are obtained by shooting the pre-set background photos; Based on the background photo photos and the raw cold atom group photos, an operation result is obtained by performing operation based on the background photo photos and the raw cold atom group photos, and the cold atom magneto-optical trap system is optimized based on the operation result; The operation based on the background photo photos and the raw cold atom group photos to obtain the operation result and the optimization of the cold atom magneto-optical trap system based on the operation result comprise the following steps: The background photo photos and the raw cold atom group photos are subtracted to obtain the operation result; The number of cold atoms in the cold atom group is calculated from the operation result based on a pre-set optimization model; The number of cold atoms in the cold atom group is calculated from the operation result based on the pre-set optimization model, which comprises the following steps: The fluorescence intensity in the operation result is optimized based on the pre-set optimization model to obtain an optimization result; The number of cold atoms in the cold atom group corresponding to the operation result is determined based on the relationship between the fluorescence intensity and the number of cold atoms in the cold atom group.

2. The method of claim 1, wherein, The mixing of the re-pump light and the pump light to obtain the cooling light, and the irradiation of the cooling light on the grating chip, and the cooperation of the nested anti-Helmholtz coil to obtain the trapped cold atom groups comprise the following steps: The cooling light is pretreated to obtain pretreated cooling light; the pretreatment comprises changing the polarization state of the cooling light and the size of the light spot; The pretreated cooling light is processed by the grating chip to obtain diffracted light, so that the nested anti-Helmholtz coil generates the trapped cold atom groups based on the diffracted light and the pretreated cooling light through its own magnetic field.

3. The method of claim 2, wherein, The nested anti-Helmholtz coil generates the trapped cold atom groups based on the diffracted light and the pretreated cooling light through its own magnetic field, which comprises the following steps: The obtained multiple radii, working currents and working point positions of the nested anti-Helmholtz coil are respectively sent to a magnetic field strength model; The magnetic field strength model integrates the multiple radii, working currents and working point positions of the nested anti-Helmholtz coil to obtain the magnetic field strength of the nested anti-Helmholtz coil, so that the trapped cold atom groups are generated based on the magnetic field strength of the nested anti-Helmholtz coil and the pretreated cooling light.

4. The method of claim 1, wherein, The laser generated by the laser is used to obtain pump light, and corresponding re-pump light is generated based on the pump light, which comprises the following steps: extracting a second laser from the laser generated by the laser device, and obtaining a third laser and pump light based on the second laser; modulating the third laser to obtain re-pump light based on an acousto-optic modulator.

5. The method of claim 1, wherein, The nested anti-Helmholtz coil is nested by an outer coil of a magnetic field with a different current direction from an inner coil of a magnetic field provided by an on-chip anti-Helmholtz coil, and the on-chip anti-Helmholtz coil is a planar coil.

6. An optimization device for a cold atom magneto-optical trap system, comprising: The cold atom magneto-optical trap system comprises a nested anti-Helmholtz coil, a grating chip, a laser device, and a CCD camera, and the device comprises: A generating module is configured to obtain pump light based on the laser generated by the laser device, and to generate corresponding re-pump light based on the pump light. An irradiating module is configured to mix the re-pump light and the pump light to obtain cooling light, and to irradiate the cooling light on the grating chip, and to obtain trapped cold atom groups in cooperation with the nested anti-Helmholtz coil. A fusing module is configured to capture an original cold atom group photo and a background photo by a CCD camera respectively, the background photo and the original cold atom group photo are captured in different anti-Helmholtz magnetic fields, the original cold atom group photo is obtained by fusing a background photo with the trapped cold atom groups based on the trapped cold atom groups and the pre-set background photo, and the background photo is obtained based on the pre-set background photo. An operating module is configured to operate the background photo and the original cold atom group photo to obtain an operating result, and to complete optimization of the cold atom magneto-optical trap system based on the operating result. The operating module comprises: A subtracting module is configured to subtract the background photo from the original cold atom group photo to obtain the operating result. A calculating module is configured to calculate the number of cold atoms in the cold atom groups from the operating result based on a pre-set optimization model. The module further comprises: An optimizing module is configured to optimize the fluorescence intensity in the operating result based on the pre-set optimization model to obtain an optimization result. A determining module is configured to determine the number of cold atoms in the cold atom groups corresponding to the operating result based on the relationship between the fluorescence intensity and the number of cold atoms in the cold atom groups.

7. An electronic device, comprising: The computer readable storage medium stores a computer program, and the computer program is executed by the processor to perform the steps of the optimization method of the cold atom magneto-optical trap system according to any one of claims 1 to 5. The computer readable storage medium stores a computer program, and the computer program is executed by the processor to perform the steps of the optimization method of the cold atom magneto-optical trap system according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, ​

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