Full-optical small atomic magnetometer three-axis remanence synchronous compensation method and system, medium

Abstract

Aiming at the problems that the existing all-optical small single-beam SERF three-axis residual magnetic field compensation technology cannot achieve three-axis synchronous compensation, has low compensation accuracy, and easily makes the working state of the magnetometer unstable, etc., the present invention provides a fast and automated three-axis residual magnetic field synchronous closed-loop compensation method and system. On the basis of applying a modulated alternating magnetic field to the sensitive axis of the SERF atomic magnetometer, only a weak detection alternating magnetic field needs to be applied to the non-sensitive axis. By performing secondary processing on the light intensity signal of the photodiode and then combining with the PID control algorithm to form a closed-loop feedback, three-axis residual magnetic field compensation can be achieved, and the compensation accuracy in the three-axis directions can reach the pT level. In addition, the light intensity of the photodiode fluctuates weakly during the compensation stage, ensuring the stable operation of other control functions, and finally enabling the atomic magnetometer to work stably in the state with the best sensitivity.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic field control of SERF atomic magnetometers, and particularly to a method and system for synchronously compensating the residual magnetism of three axes of an all-optical small atomic magnetometer, and a medium. Background Art

[0002] The spin-exchange relaxation-free (SERF) atomic magnetometer is a new type of ultra-high-sensitivity quantum ultra-weak magnetic (fT level) sensing technology. Relying on its advantages of high sensitivity, miniaturization, portability, and the ability to work at room temperature, it has been widely used in many fields such as cardio-cerebral biomagnetic detection, ultra-low-field nuclear magnetic resonance, and precision measurement. Among them, the all-optical small single-beam SERF atomic magnetometer can realize functions such as laser frequency stabilization control, atomic cell heating temperature control, residual magnetism compensation, and ultra-weak magnetic signal detection only by relying on the light intensity feedback of the photodiode, which can effectively reduce internal components and simplify the structure, thereby further realizing the micro-miniaturization of the atomic magnetometer probe.

[0003] To ensure that the SERF atomic magnetometer can achieve high-sensitivity measurement, in addition to heating the gas cell to a sufficient temperature to achieve a high alkali metal atomic particle density, it is also necessary to place it in an almost zero magnetic field environment. However, simply through a passive magnetic shielding device, there is still a certain amount of residual magnetism inside. Coupled with the influence of the residual magnetism brought by the internal components of the small SERF atomic magnetometer probe, the magnetometer cannot achieve the optimal detection of sensitivity, and even cannot be in the SERF state. Therefore, it is necessary to use an internal three-axis coil and an active magnetic field compensation method to compensate the three-axis residual magnetism to zero. The traditional all-optical small single-beam SERF three-axis residual magnetism compensation technology applies a large-range scanning magnetic field of dozens of nT to the three-axis coils respectively, and seeks the extreme point of the photodiode light intensity as the basis for judging the compensation zero point. However, this method cannot compensate the three axes synchronously, resulting in low compensation accuracy and unable to make the magnetometer truly work in a zero magnetic field environment. In addition, the large-range scanning magnetic field will cause obvious fluctuations in the photodiode light intensity, seriously affecting other functions based on light intensity feedback, such as laser frequency stabilization control and gas cell heating temperature control, and ultimately leading to unstable working conditions of the atomic magnetometer. Summary of the Invention

[0004] To achieve the above objects and other advantages of the present invention, the first object of the present invention is to provide a method for synchronously compensating the residual magnetism of three axes of an all-optical small atomic magnetometer, including the following steps:

[0005] Applying a modulated AC signal to the sensitive axis of the atomic magnetometer;

[0006] Applying weak detection signals with different frequencies to the non-sensitive axes of the atomic magnetometer;

[0007] Generating a demodulation signal for the output signal of the atomic magnetometer according to the frequency of the modulated AC signal;

[0008] Process the demodulation signal in combination with the frequency of the weak detection signal to generate a DC signal corresponding to each direction;

[0009] Apply a DC magnetic field to each direction based on the DC signal corresponding to each direction to form a closed loop, so that the corresponding DC signal is zero, and complete the residual magnetic compensation for each direction;

[0010] Turn off the output of the weak detection signal in the direction of the non-sensitive axis to complete the synchronous residual magnetic compensation of the three axes.

[0011] Further, the sensitive axis is perpendicular to the direction of light and is set as the z-axis.

[0012] Further, the number of non-sensitive axes is two, perpendicular to the sensitive axis, and are the x-axis and the y-axis respectively.

[0013] Further, the step of generating a demodulation signal for the output signal of the atomic magnetometer according to the frequency of the modulated AC signal includes:

[0014] Generate a demodulation signal from the output signal of the photodiode of the atomic magnetometer through a first lock-in amplifier, and the reference signal frequency of the first lock-in amplifier is the same as the frequency of the modulated AC signal in the z-axis direction;

[0015] The demodulation signal after lock-in amplification is synchronously output to the three-axis directions for residual magnetic compensation.

[0016] Further, the step of processing the demodulation signal in combination with the frequency of the weak detection signal to generate a DC signal corresponding to each direction includes:

[0017] Perform low-pass filtering on the demodulation signal to form a first DC signal and output it to a first PID controller;

[0018] Generate a second DC signal from the demodulation signal through a second lock-in amplifier and output it to a second PID controller, and the reference signal frequency of the second lock-in amplifier is the same as the frequency of the detection signal applied in the y-axis direction;

[0019] Generate a third DC signal from the demodulation signal through a third lock-in amplifier and output it to a third PID controller, and the reference signal frequency of the third lock-in amplifier is the same as the frequency of the detection signal applied in the x-axis direction.

[0020] Further, the step of applying a DC magnetic field to each direction based on the DC signal corresponding to each direction to form a closed loop, so that the corresponding DC signal is zero, and complete the residual magnetic compensation for each direction includes:

[0021] The first PID controller forms a closed loop by applying a DC magnetic field to the z-axis coil to make the first DC signal zero, completing the residual magnetism compensation in the z-axis direction;

[0022] The second PID controller forms a closed loop by applying a DC magnetic field to the x-axis coil to make the second DC signal zero, completing the residual magnetism compensation in the x-axis direction;

[0023] The third PID controller forms a closed loop by applying a DC magnetic field to the y-axis coil to make the third DC signal zero, completing the residual magnetism compensation in the y-axis direction.

[0024] Further, the target values of the first PID controller, the second PID controller, and the third PID controller are all set to 0.

[0025] Further, the specific operation of closing the output of the weak detection signal in the non-sensitive axis direction is to close the weak detection signals in the x-axis and y-axis directions.

[0026] The second object of the present invention is to provide a computer-readable storage medium, on which program instructions are stored, and when the program instructions are executed by a processor, the above-mentioned method is implemented.

[0027] The third object of the present invention is to provide a three-axis residual magnetism synchronous compensation system for an all-optical small atomic magnetometer, which implements the above-mentioned method, including a main controller, multiple digital-to-analog conversion chips, a transimpedance amplifier circuit, and an analog-to-digital conversion chip; wherein,

[0028] The transimpedance amplifier circuit is used to perform A / V conversion on the output signal of the atomic magnetometer probe, digitize it through the analog-to-digital conversion chip, and input the digital detection signal into the main controller;

[0029] The main controller is used to generate a modulated AC signal, a weak detection signal, and a PID controller signal. The modulated AC signal, the weak detection signal, and the PID controller signal are all converted into analog signals through the corresponding digital-to-analog conversion chips and respectively output to the sensitive axis coil and the non-sensitive axis coil of the atomic magnetometer; and process the digital detection signal according to the frequency of the modulated AC signal to generate a demodulated signal, and process the demodulated signal in combination with the frequency of the weak detection signal to generate a DC signal corresponding to each direction. According to the DC signal corresponding to each direction and the PID controller signal, a DC magnetic field is applied to each direction to form a closed loop, so that the corresponding DC signal is zero, completing the residual magnetism compensation in each direction, and closing the output of the weak detection signal in the non-sensitive axis direction to complete the three-axis residual magnetism synchronous compensation.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] Aiming at the problems that the existing all-optical small single-beam SERF three-axis residual magnetic compensation technology cannot achieve three-axis synchronous compensation, has low compensation accuracy, and easily makes the working state of the magnetometer unstable, etc., the present invention provides a fast and automated three-axis residual magnetic synchronous closed-loop compensation method and system. On the basis of applying a modulated alternating magnetic field to the sensitive axes of the SERF atomic magnetometer, only a weak detection alternating magnetic field needs to be applied to the non-sensitive axes. By performing secondary processing on the light intensity signal of the photodiode and combining with the PID control algorithm to form a closed-loop feedback, three-axis residual magnetic compensation can be achieved, enabling the compensation accuracy in all three-axis directions to reach the pT level. In addition, the light intensity of the photodiode fluctuates weakly during the compensation stage, ensuring the stable operation of other control functions, and finally enabling the atomic magnetometer to operate stably in the state with the optimal sensitivity.

[0032] The three-axis residual magnetic synchronous closed-loop compensation method for an all-optical small atomic magnetometer provided by the present invention can achieve three-axis residual magnetic synchronous compensation, thereby effectively suppressing the inaccurate three-axis residual magnetic compensation caused by the non-orthogonality of the internal coils of the probe.

[0033] The present invention provides a three-axis residual magnetic synchronous closed-loop compensation system for an all-optical small atomic magnetometer, which takes a main controller, a digital-to-analog conversion chip (DAC), and an analog-to-digital conversion chip (ADC) as the core, and can achieve high-precision and fast three-axis residual magnetic synchronous closed-loop compensation for the SERF atomic magnetometer.

[0034] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it in accordance with the content of the specification, the following takes the preferred embodiments of the present invention and combines with the accompanying drawings to describe in detail as follows. The specific implementation manners of the present invention are given in detail by the following embodiments and their accompanying drawings. Description of the Drawings

[0035] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and the schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0036] Figure 1 Flow chart of the three-axis residual magnetic synchronous compensation method for the all-optical small atomic magnetometer in Embodiment 1 Figure 1 ;

[0037] Figure 2 Flow chart of the three-axis residual magnetic synchronous compensation method for the all-optical small atomic magnetometer in Embodiment 1 Figure 2 ;

[0038] Figure 3 Flow chart of the demodulation signal generation in Embodiment 1;

[0039] Figure 4 Flow chart of the DC signal generation in Embodiment 1;

[0040] Figure 5 The residual magnetism compensation flow chart for each direction of Example 1;

[0041] Figure 6 This is the schematic diagram of the lock-in amplifier;

[0042] Figure 7 This is a schematic diagram of a three-axis residual magnetism synchronous compensation system of an all-optical small atomic magnetometer according to Example 2;

[0043] Figure 8 This is a schematic diagram of the three-axis residual magnetism compensation results;

[0044] Figure 9 is a schematic diagram of an electronic device of Example 3;

[0045] Figure 10 This is a schematic diagram of the storage medium of Example 4. DETAILED DESCRIPTION

[0046] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. It should be noted that, under the premise of no conflict, the embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0047] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0048] The figure numbers in this application are only used to distinguish the various steps in the scheme, and are not used to limit the execution order of the various steps. The specific execution order is subject to the description in the specification.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0050] Example 1

[0051] A three-axis residual magnetism synchronous compensation method for an all-optical small atomic magnetometer, such as Figure 1 , Figure 2 As shown, the following steps are included:

[0052] S1. Apply a modulated AC signal to the sensitive axis of the atomic magnetometer;

[0053] S2, applying weak detection signals of different frequencies to the non-sensitive axis of the atomic magnetometer;

[0054] The all-optical small SERF atomic magnetometer is used in this embodiment. To achieve highly sensitive ultra-weak magnetic detection, a modulation magnetic field needs to be applied in the direction perpendicular to the light. This direction is the measurement sensitive axis, designated as the z-axis. The modulation alternating magnetic field is ω z which is the modulation frequency. When there is a three-axis remanent magnetism, the light intensity of the photodiode inside the atomic magnetometer probe has a z first-order component, and this component can be expressed as:

[0055]

[0056]

[0057] where Γ = R op + R rel , the modulation factor J0, J1 are Bessel functions of the first kind.

[0058] At this time, weak detection alternating magnetic fields with different frequencies are applied to the coils of the two non-sensitive axes (x-axis and y-axis) perpendicular to the sensitive axis At this time, in formula (2) can be simplified to:

[0059]

[0060] where is the three-axis remanent magnetism of the surrounding environment, k x , k y , k z are fixed coefficients. In this way, the three variables in formula (3) are respectively proportional to the three-axis remanent magnetism components of the surrounding environment. Adjusting these three variables to zero can achieve the compensation of the three-axis remanent magnetism of the surrounding environment.

[0061] Combining the above analysis, in this embodiment, a modulation alternating signal is applied in the direction of the z-axis coil of the atomic magnetometer sensitive axis, and the modulation frequency is ω z ; synchronously, weak detection signals with different frequencies are applied in the directions of the non-sensitive axis x-axis and y-axis coils, and the signal frequencies are ω x , ω y .

[0062] S3. Generate a demodulation signal for the output signal of the atomic magnetometer according to the frequency of the modulation alternating signal;

[0063] In some embodiments, as Figure 3 shown, the step of generating a demodulation signal for the output signal of the atomic magnetometer according to the frequency of the modulation alternating signal includes:

[0064] S31. Synchronously, the output signal of the photodiode of the atomic magnetometer is demodulated by a first lock-in amplifier to generate a demodulation signal. The reference signal frequency of the first lock-in amplifier ( Figure 2 the lock-in amplifier 1 therein) is the same as the frequency of the modulated AC signal in the z-axis direction, which is ω z ;

[0065] S32. The demodulation signal after lock-in amplification is synchronously output for residual magnetic compensation in three-axis directions.

[0066] S4. Process the demodulation signal in combination with the frequency of the weak detection signal to generate a DC signal corresponding to each direction;

[0067] In some embodiments, as Figure 4 shown, the step of processing the demodulation signal in combination with the frequency of the weak detection signal to generate a DC signal corresponding to each direction includes:

[0068] S41. Perform low-pass filtering on the demodulation signal to form a first DC signal ( Figure 2 the DC signal 1 therein) and output it to a first PID controller ( Figure 2 the PID controller 1 therein);

[0069] S42. Generate a second DC signal ( Figure 2 the DC signal 2 therein) by passing the demodulation signal through a second lock-in amplifier ( Figure 2 the lock-in amplifier 2 therein) and output it to a second PID controller ( Figure 2 the PID controller 2 therein). The reference signal frequency of the second lock-in amplifier is the same as the frequency of the detection signal applied in the y-axis direction, which is ω y ;

[0070] S43. Generate a third DC signal ( Figure 2 the DC signal 3 therein) by passing the demodulation signal through a third lock-in amplifier ( Figure 2 the lock-in amplifier 3 therein) and output it to a third PID controller ( Figure 2 the PID controller 3 therein). The reference signal frequency of the third lock-in amplifier is the same as the frequency of the detection signal applied in the x-axis direction, which is ω x .

[0071] The lock-in amplifier in the above embodiments is used to extract the amplitude of the frequency ω component in the detection signal. Its principle is as Figure 6 shown. By setting a reference signal with the same frequency and phase as the frequency ω component of the detection signal, multiplying it with the detection signal through a multiplier, and then completing demodulation through a low-pass filter, the amplitude A of the frequency ω component in the detection signal can be extracted.

[0072] S5. Apply a DC magnetic field in each direction according to the DC signal corresponding to each direction to form a closed loop, so that the corresponding DC signal is zero, and complete the residual magnetism compensation in each direction;

[0073] In some embodiments, as Figure 5 shown, the step of applying a DC magnetic field in each direction according to the DC signal corresponding to each direction to form a closed loop, so that the corresponding DC signal is zero, and completing the residual magnetism compensation in each direction includes:

[0074] S51. The first PID controller forms a closed loop by applying a DC magnetic field to the z-axis coil to make the first DC signal zero, and completes the residual magnetism compensation in the z-axis direction;

[0075] S52. The second PID controller forms a closed loop by applying a DC magnetic field to the x-axis coil to make the second DC signal zero, and completes the residual magnetism compensation in the x-axis direction;

[0076] S53. The third PID controller forms a closed loop by applying a DC magnetic field to the y-axis coil to make the third DC signal zero, and completes the residual magnetism compensation in the y-axis direction.

[0077] The PID controllers in the above embodiments adopt the PID control algorithm, and their target values are all set to 0.

[0078] S6. Turn off the output of the weak detection signal in the non-sensitive axis direction to complete the three-axis residual magnetism synchronous compensation.

[0079] In some embodiments, the turning off the output of the weak detection signal in the non-sensitive axis direction is specifically to turn off the weak detection signals in the x-axis and y-axis directions.

[0080] This embodiment provides a fast and automated three-axis residual magnetism synchronous closed-loop compensation method for a full-optical small SERF atomic magnetometer. In addition to applying the three-axis compensation residual magnetism, only a weak AC detection signal needs to be applied, which will not cause fluctuations in the detected light intensity of the photodiode of the atomic magnetometer. Therefore, the stable operation of other control modules can be ensured, the three-axis residual magnetism synchronous compensation can be realized, thereby effectively suppressing the inaccurate three-axis residual magnetism compensation caused by the non-orthogonality of the internal coils of the probe, and solving the problems that the traditional method cannot achieve three-axis synchronous compensation, the compensation accuracy is low, and it is easy to make the working state of the magnetometer unstable.

[0081] Embodiment 2

[0082] For a detailed description of the three-axis residual magnetism synchronous compensation method for a full-optical small atomic magnetometer, reference can be made to the corresponding description in the above method embodiments, and details are not described herein again.

[0083] To implement a three-axis residual magnetism synchronous compensation system for a full-optical small atomic magnetometer in the above Embodiment 1, as Figure 7As shown, it includes a main controller, multiple digital-to-analog conversion chips (DACs), a transimpedance amplifier circuit, and an analog-to-digital conversion chip (ADC); among them,

[0084] The light intensity of the internal photodiode of the atomic magnetometer probe is converted from A / V through the transimpedance amplifier circuit and then digitized by the analog-to-digital conversion chip, and the digital detection signal is input into the main controller; a reference signal is generated inside the main controller It is multiplied with the digital detection signal through a multiplier and a low-pass filter 1 to generate a demodulation signal, and the demodulation signal is synchronously distributed to the three-axis remanence compensation module in three channels;

[0085] A digital modulation signal is generated inside the main controller It is converted into an analog signal through the digital-to-analog conversion chip (DAC1) and output to the z-axis coil inside the atomic magnetometer probe; at the same time, a detection signal is generated inside the main controller The detection signal 1 is converted into an analog signal through DAC2 and output to the x-axis coil inside the atomic magnetometer probe; synchronously, a detection signal is generated inside the main controller The detection signal 2 is converted into an analog signal through DAC3 and output to the y-axis coil inside the atomic magnetometer probe;

[0086] The main controller includes a z-axis remanence compensation module, a y-axis remanence compensation module, and an x-axis remanence compensation module.

[0087] For the z-axis remanence compensation module, the demodulation signal is processed through a low-pass filter 2 to form a DC signal and input to PID1 (i.e., the first PID controller), the target value of PID1 is set to 0, and its control quantity is converted into an analog signal through DAC4 and loaded on the z-axis coil to generate a DC compensation magnetic field to cancel the remanence in the z-axis direction, thus completing the remanence compensation in the z-axis direction;

[0088] For the x-axis remanence compensation module, the demodulation signal is multiplied with the reference signal The frequency of the reference signal 2 is ω y and is processed through a low-pass filter 2 to form a DC signal and input to PID2 (i.e., the second PID controller), the target value of PID2 is set to 0, and its control quantity is converted into an analog signal through DAC5 and loaded on the x-axis coil to generate a DC compensation magnetic field to cancel the remanence in the x-axis direction, thus completing the remanence compensation in the x-axis direction;

[0089] For the y-axis remanence compensation module, the demodulation signal is multiplied with the reference signal The frequency of the reference signal 3 is ω xand is processed with a low-pass filter 2 to form a DC signal and input to a PID3 (i.e., the third PID controller). The target value of the PID3 is set to 0, and its control quantity is converted into an analog signal via a DAC6 and loaded on the y-axis coil to generate a DC compensation magnetic field to cancel the residual magnetism in the y-axis direction, thereby completing the residual magnetism compensation in the y-axis direction;

[0090] After the outputs of the PID1, PID2, and PID3 are stable, turn off the outputs of the detection signal 1 and the detection signal 2 to complete the synchronous compensation of the three-axis residual magnetism.

[0091] This embodiment provides a fast and automated three-axis residual magnetism synchronous closed-loop compensation system for a full-optical small SERF atomic magnetometer. The start and end moments of the three-axis residual magnetism compensation module compensation process are synchronous, which can effectively suppress the inaccurate three-axis residual magnetism compensation caused by the non-orthogonality of the internal coils of the probe. This system takes the main controller, ADC, and DAC chips as the core and realizes the three-axis residual magnetism synchronous closed-loop compensation of the SERF atomic magnetometer with high precision and speed.

[0092] Based on the three-axis residual magnetism closed-loop compensation method and system for a full-optical small SERF atomic magnetometer provided by the present invention, fast three-axis residual magnetism compensation can be realized in 5 - 10 s fully automatically. As Figure 8 shown, magnetic fields of ±25 nT are applied in the x, y, and z three-axis directions respectively. A compensation accuracy of 3.5 pT can be achieved in the sensitive axis z-axis direction, and 20.3 pT and 69.4 pT can be achieved in the non-sensitive axis x-axis and y-axis directions respectively.

[0093] Embodiment 3

[0094] An electronic device, as Figure 9 shown, includes: a memory on which program code is stored; a processor connected to the memory, and when the program code is executed by the processor, a method for synchronous compensation of three-axis residual magnetism of a full-optical small atomic magnetometer is implemented. For a detailed description of the method, reference can be made to the corresponding description in the above method embodiment, and details will not be repeated here.

[0095] Embodiment 4

[0096] A computer-readable storage medium, as Figure 10 shown, on which program instructions are stored, and when the program instructions are executed by a processor, a method for synchronous compensation of three-axis residual magnetism of a full-optical small atomic magnetometer is implemented. For a detailed description of the method, reference can be made to the corresponding description in the above method embodiment, and details will not be repeated here.

[0097] The number of devices and the processing scale described here are used to simplify the description of the present invention. Applications, modifications, and variations of the present invention will be obvious to those skilled in the art.

[0098] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and the illustrated and described examples here.

[0099] The devices, electronic devices, non-volatile computer storage media, and methods provided in the embodiments of this specification are corresponding. Therefore, the devices, electronic devices, and non-volatile computer storage media also have beneficial technical effects similar to those of the corresponding methods. Since the beneficial technical effects of the methods have been described in detail above, the beneficial technical effects of the corresponding devices, electronic devices, and non-volatile computer storage media will not be elaborated here.

[0100] Those skilled in the art also know that in addition to implementing the controller in the form of pure computer-readable program code, the method steps can be logically programmed to enable the controller to be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, etc. to achieve the same functions. Therefore, such a controller can be regarded as a hardware component, and the devices included therein for implementing various functions can also be regarded as the structures within the hardware component. Or even, the devices for implementing various functions can be regarded as both software units for implementing the method and the structures within the hardware component.

[0101] The systems, devices, or units illustrated in the above embodiments can be specifically implemented by computer chips or entities, or by products with certain functions. For the convenience of description, when describing the above devices, they are divided into various units according to functions and described separately. Of course, when implementing one or more embodiments of this specification, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0102] Those skilled in the art should understand that the embodiments of this specification can be provided as methods, systems, or computer program products. Therefore, the embodiments of this specification can take the form of completely hardware embodiments, completely software embodiments, or embodiments combining software and hardware aspects. Moreover, the embodiments of this specification can take the form of computer program products implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program code.

[0103] This specification is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the specification. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to produce a machine, such that the instructions executed by the processors of the computer or other programmable data processing devices generate means for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or in multiple blocks.

[0104] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufacture including instruction means that implement the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or in multiple blocks.

[0105] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or in multiple blocks.

[0106] It should also be noted that the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, commodity or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, commodity or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, commodity or device comprising the element.

[0107] This specification can be described in the general context of computer-executable instructions executed by a computer, such as program units. Generally, program units include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The specification can also be practiced in a distributed computing environment where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program units can be located in local and remote computer storage media including storage devices.

[0108] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the key point of each embodiment is to illustrate the differences from other embodiments. In particular, for system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and reference can be made to the corresponding parts of the method embodiments for the relevant content.

[0109] The above is only for the embodiments of this specification and is not intended to limit one or more embodiments of this specification. For those skilled in the art, various changes and modifications can be made to one or more embodiments of this specification. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of one or more embodiments of this specification shall be included within the scope of the claims of one or more embodiments of this specification.

Claims

1. A method for synchronously compensating the residual magnetism of three axes of an all-optical small atomic magnetometer, characterized in that, It includes the following steps: Apply a modulated alternating current signal to the sensitive axis of the atomic magnetometer; Apply weak detection signals with different frequencies to the non-sensitive axes of the atomic magnetometer; Generate a demodulation signal for the output signal of the atomic magnetometer according to the frequency of the modulated alternating current signal; Process the demodulation signal in combination with the frequency of the weak detection signal to generate a DC signal corresponding to each direction; Apply a DC magnetic field to each direction according to the DC signal corresponding to each direction to form a closed loop, so that the corresponding DC signal is zero, and complete the remanence compensation for each direction; Turn off the output of the weak detection signal in the non-sensitive axis direction to complete the three-axis remanence synchronous compensation; The sensitive axis is perpendicular to the direction of light and is set as the z-axis; The number of non-sensitive axes is two, perpendicular to the sensitive axis, and are the x-axis and y-axis respectively; The step of generating a demodulation signal for the output signal of the atomic magnetometer according to the frequency of the modulated alternating current signal includes: Generate a demodulation signal for the output signal of the photodiode of the atomic magnetometer through a first lock-in amplifier, and the reference signal frequency of the first lock-in amplifier is the same as the frequency of the modulated alternating current signal in the z-axis direction; The demodulation signal after lock-in amplification is synchronously output to the three axes for remanence compensation; The step of processing the demodulation signal in combination with the frequency of the weak detection signal to generate a DC signal corresponding to each direction includes: Perform low-pass filtering on the demodulation signal to form a first DC signal and output it to a first PID controller; Generate a second DC signal for the demodulation signal through a second lock-in amplifier and output it to a second PID controller, and the reference signal frequency of the second lock-in amplifier is the same as the frequency of the detection signal applied in the y-axis direction; Generate a third DC signal for the demodulation signal through a third lock-in amplifier and output it to a third PID controller, and the reference signal frequency of the third lock-in amplifier is the same as the frequency of the detection signal applied in the x-axis direction; The step of applying a DC magnetic field to each direction according to the DC signal corresponding to each direction to form a closed loop, so that the corresponding DC signal is zero, and complete the remanence compensation for each direction includes: The first PID controller forms a closed loop by applying a DC magnetic field to the z-axis coil to make the first DC signal zero, and completes the remanence compensation in the z-axis direction; The second PID controller forms a closed loop by applying a DC magnetic field to the x-axis coil to make the second DC signal zero, and completes the remanence compensation in the x-axis direction; The third PID controller forms a closed loop by applying a DC magnetic field to the y-axis coil to make the third DC signal zero, and completes the remanence compensation in the y-axis direction.

2. A method for synchronously compensating the three-axis remanence of an all-optical small atomic magnetometer according to claim 1, characterized in that: The target values of the first PID controller, the second PID controller, and the third PID controller are all set to 0.

3. A method for synchronously compensating the three-axis residual magnetism of an all-optical small atomic magnetometer as described in claim 1, characterized in that: The specific step of turning off the output of the weak detection signal in the non-sensitive axis direction is to turn off the weak detection signals in the x-axis and y-axis directions.

4. A computer-readable storage medium, characterized in that, It stores program instructions, and when the program instructions are executed by a processor, the method described in any one of claims 1 to 3 is implemented.

5. A three-axis residual magnetic synchronous compensation system for an all-optical small atomic magnetometer, which implements the method according to any one of claims 1 to 3, characterized in that: It includes a main controller, multiple digital-to-analog conversion chips, a transimpedance amplifier circuit, and an analog-to-digital conversion chip; wherein, The transimpedance amplifier circuit is used to perform A / V conversion on the output signal of the atomic magnetometer probe, digitize it through the analog-to-digital conversion chip, and input the digital detection signal into the main controller; The main controller is used to generate a modulation AC signal, a weak detection signal, and a PID controller signal. The modulation AC signal, the weak detection signal, and the PID controller signal are all converted into analog signals through the corresponding digital-to-analog conversion chips and respectively output to the sensitive axis coil and the non-sensitive axis coil of the atomic magnetometer; and process the digital detection signal according to the frequency of the modulation AC signal to generate a demodulation signal, and process the demodulation signal in combination with the frequency of the weak detection signal to generate a DC signal corresponding to each direction. Apply a DC magnetic field to each direction according to the DC signal corresponding to each direction in combination with the PID controller signal to form a closed loop, so that the corresponding DC signal is zero, complete the remanence compensation in each direction, and turn off the output of the weak detection signal in the non-sensitive axis direction to complete the three-axis remanence synchronous compensation.

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