阅读说明：本技术 磁场梯度测量装置 (Magnetic field gradient measuring device ) 是由 张笑楠 杨仁福 魏小刚 杜艺杰 罗文浩 丛楠 于 2021-06-30 设计创作，主要内容包括：本申请涉及一种磁场梯度测量装置,包括激光处理模块、第一磁感应模块以及第二磁感应模块,将第一磁感应模块和第二磁感应模块设置于待测磁场中,第一磁感应模块包括第一原子气室、第一反光镜和第一探测器,第二磁感应模块包括第二原子气室、第二反光镜和第二探测器；本申请实施例中的磁场梯度测量装置,在每一个磁感应模块中均设置了反光镜,通过该反光镜使单向穿过磁感应模块中的原子气室的激光折返后,再次穿过原子气室,通过折返光路来增加激光经过原子气室的光程,进而增加与激光作用的原子数,能够有效降低原子气室的工作温度,提高梯度测量装置的灵敏度,且由于无需增加额外的隔热装置、系统功耗更低,能够降低磁场梯度测量装置的制作成本。(The application relates to a magnetic field gradient measuring device, which comprises a laser processing module, a first magnetic induction module and a second magnetic induction module, wherein the first magnetic induction module and the second magnetic induction module are arranged in a magnetic field to be measured; the magnetic field gradient measuring device in the embodiment of the application, the reflector is arranged in each magnetic induction module, after the laser passing through the atomic air chamber in the magnetic induction module in one direction is turned back through the reflector, the laser passes through the atomic air chamber again, the optical path of the laser passing through the atomic air chamber is increased through the light path turned back, the atomic number acting on the laser is increased, the working temperature of the atomic air chamber can be effectively reduced, the sensitivity of the gradient measuring device is improved, and the magnetic field gradient measuring device can be reduced due to the fact that an additional heat insulation device does not need to be added, the power consumption of the system is lower.)

1. A magnetic field gradient measurement apparatus, characterized in that the magnetic field gradient measurement apparatus comprises: the magnetic induction system comprises a laser processing module, a first magnetic induction module and a second magnetic induction module, wherein the first magnetic induction module and the second magnetic induction module are arranged in a magnetic field to be detected; the atoms in the first atomic gas cell and the second atomic gas cell are the same;

the laser processing module is configured to input a first optical signal to the first atomic gas chamber and the second atomic gas chamber, where a self frequency of the first optical signal is consistent with a transition frequency of the atom, and the first optical signal is an optical signal subjected to amplitude modulation;

the first detector is used for acquiring first intensity information of a second optical signal after the first optical signal is input by the laser processing module, and sending the first intensity information to the laser processing module; the second optical signal is formed after the first optical signal is input into the first atomic gas chamber and returns to the first atomic gas chamber through the first reflector, and the first intensity information includes the intensity of the second optical signal under the first optical signal after amplitude modulation;

the second detector is configured to obtain second intensity information of a third optical signal after the first optical signal is input by the laser processing module, and send the second intensity information to the laser processing module; the third optical signal is formed after the first optical signal is input into the second atomic gas chamber and returns to the second atomic gas chamber through the second reflector, and the second intensity information includes intensity of the third optical signal under the first optical signal after multiple amplitude modulations;

the laser processing module is further configured to determine a magnetic field gradient of the magnetic field to be measured according to the first intensity information, the second intensity information, the gyromagnetic ratio of the atom, and the distance information; wherein the distance information is a distance between the first atomic gas cell and the second atomic gas cell.

2. Magnetic field gradient measurement apparatus according to claim 1,

the laser processing module is specifically configured to determine a first precession frequency of an atom in the first atom gas chamber according to the first intensity information, and determine a second precession frequency of an atom in the second atom gas chamber according to the second intensity information;

the laser processing module is further configured to determine a magnetic field gradient of the magnetic field to be measured according to the first precession frequency, the second precession frequency, the gyromagnetic ratio of the atom, and the distance information.

3. Magnetic field gradient measurement apparatus according to claim 2,

the laser processing module is specifically configured to determine a magnetic field gradient of the magnetic field to be measured according to a difference between the first precession frequency and the second precession frequency, and a ratio between the gyromagnetic ratio of the atom and the distance information.

4. The magnetic field gradient measurement device of any of claims 1 to 3, wherein the laser processing module comprises: the laser device comprises a laser device, a laser control module and a laser beam splitter;

the laser is used for outputting the first optical signal, and the self frequency of the first optical signal is consistent with the transition frequency of the atom;

the laser control module is used for carrying out amplitude modulation on the first optical signal;

the laser beam splitter is used for splitting the first optical signal after amplitude modulation and respectively inputting the first optical signal into the first atomic gas chamber and the second atomic gas chamber.

5. The magnetic field gradient measurement device of claim 4, wherein the laser processing module further comprises: a laser transmission module;

the laser transmission module is configured to transmit the first optical signal output by the laser control module after amplitude modulation to the laser beam splitter, so that the first optical signal is split by the laser beam splitter and then is input to the first atomic gas chamber and the second atomic gas chamber respectively.

6. The magnetic field gradient measurement device of claim 5, wherein the laser processing module further comprises a first fiber coupler and a second fiber coupler, the first magnetic induction module further comprises a first birefringent single crystal waveplate, and the second magnetic induction module further comprises a second birefringent single crystal waveplate;

the first optical fiber coupler is used for coupling the first optical signal into the laser transmission module;

the second optical fiber coupler is used for collimating the first optical signal transmitted by the laser transmission module and then inputting the collimated first optical signal to the laser beam splitter;

the first birefringent single crystal wave plate is used for adjusting the polarization state of a first optical signal input to the first atomic gas chamber by the laser beam splitter into circularly polarized light and then inputting the circularly polarized light to the first atomic gas chamber;

and the second birefringent single crystal wave plate is used for adjusting the polarization state of the first optical signal input to the second atom air chamber by the laser beam splitter into circularly polarized light and then inputting the circularly polarized light to the second atom air chamber.

7. The magnetic field gradient measurement device of claim 6, wherein the laser processing module further comprises: a half wave plate;

the half wave plate is used for adjusting the linear polarization state of the first optical signal output by the second optical fiber coupler.

8. The magnetic field gradient measurement device of claim 7, wherein the laser processing module further comprises: a difference module;

the difference module is configured to receive the first intensity information sent by the first detector and the second intensity information sent by the second detector;

the difference module is further configured to send a difference result between the first intensity information and the second intensity information to the laser control module.

9. The magnetic field gradient measurement device of claim 4, wherein the laser control module comprises a laser modulator and a control unit;

the control unit is configured to control the laser modulator to output modulation signals with different frequencies, where the modulation signals are configured to perform amplitude modulation on the first optical signal.

10. The magnetic field gradient measurement device of claim 5, wherein the laser delivery module is a single mode polarization maintaining fiber.

Technical Field

The application relates to the technical field of magnetic field gradient measurement, in particular to a magnetic field gradient measuring device.

Background

With the development of magnetic field measurement technology, the requirements on the measurement accuracy of magnetic field intensity detection and magnetic field gradient detection are higher and higher, and the atomic optical pump gradiometer has the advantage of ultrahigh sensitivity, and has been widely applied to the field of weak magnetic precision measurement such as biomedicine and nondestructive inspection.

In the traditional technology, an atomic light pump gradiometer emits a single beam of laser through a laser light source, the beam is split to act on atomic gas chambers in a plurality of probes, the atomic gas chambers interact with atoms, the light intensity is detected by a detector, the lamor precession frequency of the atoms under different magnetic fields is identified according to light intensity signals, the magnetic field intensity is calculated according to the gyromagnetic ratio of alkali metal atoms, and finally the gradient of the magnetic field to be detected is determined.

In the current atomic light pump gradiometer, the volume of the atomic gas chamber is reduced after the probe is miniaturized, so the atomic number acted with the laser is generally required to be increased by increasing the temperature of the atomic gas chamber so as to ensure the sensitivity of the atomic light pump gradiometer. However, the high temperature of the atomic gas chamber can cause the working temperature of the probe to be high, the power consumption of the instrument is increased, and an additional heat insulation device is required, so that the cost of the atomic optical pump gradiometer is high.

Disclosure of Invention

Therefore, it is necessary to provide a gradiometer capable of increasing the atomic number acting on the laser at a lower temperature to improve the sensitivity of the gradiometer, solve the problems of large power consumption of the gradiometer due to the overhigh temperature of the atomic gas chamber and high instrument cost caused by the addition of an additional heat insulation device, reduce the power consumption of the atomic optical pump gradiometer, and reduce the manufacturing cost of the atomic optical pump gradiometer.

A magnetic field gradient measurement apparatus, comprising: the device comprises a laser processing module, a first magnetic induction module and a second magnetic induction module, wherein the first magnetic induction module and the second magnetic induction module are arranged in a magnetic field to be detected; the atoms in the first atomic gas chamber and the second atomic gas chamber are the same;

the laser processing module is used for inputting a first optical signal to the first atomic gas chamber and the second atomic gas chamber, the self frequency of the first optical signal is consistent with the transition frequency of atoms, and the first optical signal is an optical signal after amplitude modulation;

the first detector is used for acquiring first intensity information of the second optical signal after the first optical signal is input into the laser processing module and sending the first intensity information to the laser processing module; the second optical signal is formed after the first optical signal is input into the first atomic gas chamber and returns to the first atomic gas chamber through the first reflector; the first intensity information comprises the intensity of the second optical signal under the first optical signal after amplitude modulation;

the second detector is used for acquiring second intensity information of the third optical signal after the first optical signal is input into the laser processing module and sending the second intensity information to the laser processing module; the third optical signal is formed after the first optical signal is input into the second atomic gas chamber and returns to the second atomic gas chamber through the second reflector; the second intensity information includes intensity of a third optical signal under the first optical signal after amplitude modulation for a plurality of times;

the laser processing module is further used for determining the magnetic field gradient of the magnetic field to be detected according to the first intensity information, the second intensity information, the gyromagnetic ratio of atoms and the distance information; wherein the distance information is a distance between the first atomic gas cell and the second atomic gas cell.

In one embodiment, the laser processing module is specifically configured to determine a first precession frequency of atoms in the first atom gas cell based on the first intensity information, and determine a second precession frequency of atoms in the second atom gas cell based on the second intensity information;

and the laser processing module is also used for determining the magnetic field gradient of the magnetic field to be detected according to the first precession frequency, the second precession frequency, the gyromagnetic ratio of atoms and the distance information.

In one embodiment, the laser processing module is specifically configured to determine the magnetic field gradient of the magnetic field to be measured according to a difference between the first precession frequency and the second precession frequency, and a ratio of the gyromagnetic ratio of the atom to the distance information.

In one embodiment, the laser processing module comprises: the laser device comprises a laser device, a laser control module and a laser beam splitter;

the laser is used for outputting a first optical signal, and the self frequency of the first optical signal is consistent with the transition frequency of atoms;

the laser control module is used for carrying out amplitude modulation on the first optical signal;

and the laser beam splitter is used for splitting the first optical signal after the amplitude modulation and respectively inputting the first optical signal into the first atomic gas chamber and the second optical signal into the second atomic gas chamber.

In one embodiment, the laser processing module further comprises: a laser transmission module;

and the laser transmission module is used for transmitting the amplitude-modulated first optical signal output by the laser control module to the laser beam splitter, so that the first optical signal is split by the laser beam splitter and then is respectively input to the first atom air chamber and the second atom air chamber.

In one embodiment, the laser processing module further comprises a first fiber coupler and a second fiber coupler, the first magnetic induction module further comprises a first birefringent single crystal waveplate, and the second magnetic induction module further comprises a second birefringent single crystal waveplate;

a first optical fiber coupler for coupling the first optical signal into the laser transmission module;

the second optical fiber coupler is used for collimating the first optical signal transmitted by the laser transmission module and then inputting the collimated first optical signal to the laser beam splitter;

the first double-refraction single crystal wave plate is used for adjusting the polarization state of a first optical signal input into the first atomic air chamber by the laser beam splitter into circularly polarized light and then inputting the circularly polarized light into the first atomic air chamber;

and the second birefringent single crystal wave plate is used for adjusting the polarization state of the first optical signal input into the second atom air chamber by the laser beam splitter into circularly polarized light and then inputting the circularly polarized light into the second atom air chamber.

In one embodiment, the laser processing module further comprises: a half wave plate;

and the half wave plate is used for adjusting the linear polarization state of the first optical signal output by the second optical fiber coupler.

In one embodiment, the laser processing module further comprises: a difference module;

the difference module is used for receiving first intensity information sent by the first detector and second intensity information sent by the second detector;

and the difference module is also used for sending the difference result of the first intensity information and the second intensity information to the laser control module.

In one embodiment, the laser control module comprises a laser modulator and a control unit;

and the control unit is used for controlling the laser modulator to output modulation signals with different frequencies, and the modulation signals are used for carrying out amplitude modulation on the first optical signals.

In one embodiment, the laser transmission module is a single-mode polarization maintaining fiber.

The magnetic field gradient measuring device comprises a laser processing module, a first magnetic induction module and a second magnetic induction module, wherein the first magnetic induction module and the second magnetic induction module are arranged in a magnetic field to be measured; the laser processing module inputs a first optical signal to the first atomic gas chamber and the second atomic gas chamber; after the laser processing module inputs the first optical signal, the first detector acquires first intensity information of a second optical signal formed after the first optical signal is input into the first atomic gas chamber and returned to the first atomic gas chamber through the first reflector, and sends the first intensity information to the laser processing module; after the laser processing module inputs the first optical signal, the second detector acquires second intensity information of a third optical signal formed after the first optical signal is input into the second atomic gas chamber and returned to the second atomic gas chamber through the second reflector, and sends the second intensity information to the laser processing module; the laser processing module determines the magnetic field gradient of the magnetic field to be measured according to the first intensity information, the second intensity information, the gyromagnetic ratio of the atoms and the distance information between the first atom air chamber and the second atom air chamber; that is to say, in the magnetic field gradient measuring apparatus in the embodiment of the present application, each magnetic induction module is provided with a reflective mirror, and the reflective mirror makes the laser passing through the atomic gas chamber in the magnetic induction module in one direction pass through the atomic gas chamber again after being turned back, and increases the optical path of the laser passing through the atomic gas chamber by the turn-back optical path, thereby increasing the atomic number acting on the laser, and being capable of effectively reducing the working temperature of the atomic gas chamber, so that the atoms in the atomic gas chamber still have more atoms interacting with the laser at a lower working temperature, and improving the sensitivity of the gradient measuring apparatus; in addition, after the temperature of the atomic gas chamber is reduced, the power consumption of the magnetic field gradient measuring device cannot be increased, and the magnetic field gradient measuring device in the embodiment of the application does not need to be additionally provided with a heat insulation device, so that the manufacturing cost of the magnetic field gradient measuring device can be reduced, and meanwhile, the structure in the embodiment is favorable for the miniaturization of the gas chamber structure.

Drawings

FIG. 1 is a schematic structural diagram of a magnetic field gradient measurement apparatus provided in an embodiment of the present application;

FIG. 2 is a schematic view of another structure of a magnetic field gradient measuring apparatus according to an embodiment of the present disclosure;

FIG. 3 is a schematic view of another structure of a magnetic field gradient measuring apparatus according to an embodiment of the present disclosure;

FIG. 4 is a schematic view of another structure of a magnetic field gradient measuring apparatus provided in an embodiment of the present application;

FIG. 5 is a schematic view of another structure of a magnetic field gradient measuring apparatus provided in an embodiment of the present application;

FIG. 6 is a schematic view of another structure of a magnetic field gradient measuring apparatus provided in an embodiment of the present application;

FIG. 7 is a schematic view of another structure of a magnetic field gradient measuring apparatus according to an embodiment of the present application;

fig. 8 is another schematic structural diagram of a magnetic field gradient measurement apparatus according to an embodiment of the present disclosure.

Description of reference numerals:

10: a laser processing module; 20: a first magnetic induction module; 30: a second magnetic induction module;

201: a first atomic gas cell; 202: a first reflective mirror; 203: a first detector;

301: a second atomic gas cell; 302: a second reflective mirror; 303: a second detector;

101: a laser; 102: a laser control module; 103: a laser beam splitter;

104: a laser transmission module; 105: a first fiber coupler; 106: a second fiber coupler;

204: a first birefringent single crystal waveplate; 304: a second birefringent single crystal wave plate;

107: a half wave plate; 108: a difference module;

1021: a laser modulator; 1022: a control unit.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

The magnetic field gradient measuring device provided by the embodiment of the application is suitable for the technical field of magnetic field gradient measurement, and the magnetic field gradient measuring device adopts the reflector to return the laser in the original path, so that the laser can pass through the atomic gas chamber in two directions, the effect of increasing the optical path of the laser is realized, namely, the atomic number acted with the laser can be increased; the magnetic field gradient measuring device can reduce the temperature of the atomic gas chamber, further reduce the cost of the gradiometer and improve the sensitivity and the accuracy of the gradiometer.

In the prior art, laser penetrates through an atom air chamber in a single direction, and after a probe is miniaturized, the atomic gas chamber is small in size, so that the optical path of the laser penetrating through the atom air chamber is short, the atomic number acted with the laser is small, and the sensitivity of a gradiometer is low; when the atomic number acted with the laser is increased by increasing the temperature of the atomic gas chamber, the problem that the working temperature of the atomic gas chamber and the probe is overhigh can occur; in practical use, the atomic gas chamber or the probe needs to be additionally provided with a heat insulation device, and the increase of the heat insulation device causes the manufacturing cost of the gradiometer to be higher.

Therefore, the magnetic field gradient measuring device provided by the embodiment of the application can solve the problem that the cost of a gradiometer is high due to the fact that the temperature of an atomic gas chamber is too high and a heat insulation device needs to be added in the prior art; in the magnetic field gradient measuring device in the embodiment, each probe is provided with a reflector, laser which passes through the atomic gas chamber in one direction is folded back through the reflector and then passes through the atomic gas chamber again, the optical path of the laser passing through the atomic gas chamber is increased through a folded light path, and the number of atoms which act with the laser is increased; by the scheme, the working temperature of the atomic gas chamber can be effectively reduced, so that atoms in the atomic gas chamber still have more atom-laser interaction at a lower working temperature, and the sensitivity of the gradient measuring device is improved; in addition, after the temperature of the atomic gas chamber is reduced, the power consumption of the magnetic field gradient measuring device cannot be increased, an additional heat insulation device does not need to be added, and the cost of the gradient measuring device can be reduced.

The following describes the technical solutions of the present application and how to solve the above technical problems with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a magnetic field gradient measurement apparatus according to an embodiment of the present application. As shown in fig. 1, the magnetic field gradient measuring apparatus includes: the system comprises a laser processing module 10, a first magnetic induction module 20 and a second magnetic induction module 30, wherein the first magnetic induction module 20 and the second magnetic induction module 30 are arranged in a magnetic field to be detected, the first magnetic induction module 20 comprises a first atom air chamber 201, a first reflector 202 and a first detector 203, and the second magnetic induction module 30 comprises a second atom air chamber 301, a second reflector 302 and a second detector 303; the atoms in the first atom gas cell 201 and the second atom gas cell 301 are the same; the laser processing module 10 is configured to input a first optical signal to the first atomic gas cell 201 and the second atomic gas cell 301, where the self frequency of the first optical signal is consistent with the transition frequency of an atom, and the first optical signal is an optical signal after amplitude modulation; the first detector 203 is configured to obtain first intensity information of the second optical signal after the laser processing module 10 inputs the first optical signal, and send the first intensity information to the laser processing module 10; the second optical signal is formed after the first optical signal is input into the first atomic gas cell 201 and returns to the first atomic gas cell 201 through the first reflective mirror 202, and the first intensity information includes the intensity of the second optical signal under the first optical signal after amplitude modulation; the second detector 303 is configured to obtain second intensity information of the third optical signal after the laser processing module 10 inputs the first optical signal, and send the second intensity information to the laser processing module 10; the third optical signal is formed after the first optical signal is input into the second atomic gas cell 301 and returns to the second atomic gas cell 301 through the second reflector 302, and the second intensity information includes the intensity of the third optical signal under the first optical signal after amplitude modulation; the laser processing module 10 is further configured to determine a magnetic field gradient of the magnetic field to be measured according to the first intensity information, the second intensity information, the gyromagnetic ratio of the atom, and the distance information; wherein the distance information is the distance between the first atom gas cell 201 and the second atom gas cell 202.

Alternatively, the atoms in the first and second atomic gas chambers 201 and 301 may be alkali metal atoms, such as: potassium (K) atoms, rubidium (Rb) atoms, cesium (Cs) atoms, and the like, the atomic transition frequencies of different types of alkali metal atoms are different, and the self frequencies of the first optical signals acting on the first atomic gas cell 201 and the second atomic gas cell 301 can be determined according to the types of atoms in the first atomic gas cell 201 and the second atomic gas cell 301; that is to say, the self frequency of the first optical signal needs to be consistent with the atomic transition frequency, and only when the self frequency of the first optical signal is equal to the atomic transition frequency and the first optical signal passes through the first atomic gas cell 201 and the second atomic gas cell 301, the energy level transition of the atoms in the first atomic gas cell 201 and the second atomic gas cell 301 can occur, so as to implement atomic polarization; then, the atoms in the first atom air chamber 201 and the second atom air chamber 301 perform Larmor precession under the action of the magnetic field to be detected; optionally, the first optical signal may be circularly polarized light or linearly polarized light, and the atoms in the first atom gas cell 201 and the second atom gas cell 202 may be rubidium atoms.

In addition, the first optical signal is an optical signal subjected to amplitude modulation, that is, the first optical signal does not continuously act on the first atomic gas cell 201 and the second atomic gas cell 301, but intermittently acts on the first atomic gas cell 201 and the second atomic gas cell 301 according to a certain amplitude modulation frequency; the laser processing module 10 can control the amplitude modulation frequencies of the first optical signal input into the first atomic gas cell 201 and the second atomic gas cell 301, and the first optical signals under different modulation frequencies all act on the first atomic gas cell 201 and the second atomic gas cell 301 at the same time.

After passing through the first atomic gas chamber 201, the first optical signal returns through the first reflector 202 in the original path, and passes through the first atomic gas chamber 201 again to form a second optical signal, and the first detector 203 acquires the intensity of the second optical signal; for the first optical signals with different modulation frequencies, the first detector 203 can detect the intensity of a second optical signal formed under the action of the first optical signals with different modulation frequencies, so as to obtain first intensity information of the second optical signal; the first intensity information includes intensities of the second optical signals at different modulation frequencies, that is, intensities of the second optical signals under the amplitude-modulated first optical signals.

The first optical signal passes through the second atomic gas chamber 301, returns in the original path through the second reflector 302, passes through the second atomic gas chamber 301 again to form a third optical signal, and the second detector 303 acquires the intensity of the third optical signal; for the first optical signals with different modulation frequencies, the second detector 303 may detect the intensity of a third optical signal formed under the action of the first optical signals with different modulation frequencies, to obtain second intensity information of the third optical signal; the second intensity information includes intensities of the third optical signals at different modulation frequencies, that is, intensities of the third optical signals under the amplitude-modulated first optical signals.

Next, the laser processing module 10 may determine the magnetic field gradient of the magnetic field to be measured according to the first intensity information sent by the first detector 203, the second intensity information sent by the second detector 303, the gyromagnetic ratio of the atom, and the distance information between the first atom gas cell 201 and the second atom gas cell 301.

The magnetic field gradient measuring device comprises a laser processing module, a first magnetic induction module and a second magnetic induction module, wherein the first magnetic induction module and the second magnetic induction module are arranged in a magnetic field to be measured; the laser processing module inputs first optical signals corresponding to different input frequencies to the first atomic gas chamber and the second atomic gas chamber; after the laser processing module inputs the first optical signal, the first detector acquires first intensity information of a second optical signal formed after the first optical signal is input into the first atomic gas chamber and returned to the first atomic gas chamber through the first reflector, and sends the first intensity information to the laser processing module; after the laser processing module inputs the first optical signal, the second detector acquires second intensity information of a third optical signal formed after the first optical signal is input into the second atomic gas chamber and returned to the second atomic gas chamber through the second reflector, and sends the second intensity information to the laser processing module; the laser processing module determines the magnetic field gradient of the magnetic field to be measured according to the first intensity information, the second intensity information, the gyromagnetic ratio of the atoms and the distance information between the first atom air chamber and the second atom air chamber; that is to say, in the magnetic field gradient measuring apparatus in the embodiment of the present application, each magnetic induction module is provided with a reflective mirror, and the reflective mirror makes the laser passing through the atomic gas chamber in the magnetic induction module in one direction pass through the atomic gas chamber again after being turned back, and increases the optical path of the laser passing through the atomic gas chamber by the turn-back optical path, so as to increase the atomic number acting on the laser, thereby effectively reducing the temperature of the atomic gas chamber, so that the atoms in the atomic gas chamber still have more atoms interacting with the laser at a lower temperature, and improving the sensitivity of the gradient measuring apparatus; in addition, after the temperature of the atomic gas chamber is reduced, the power consumption of the magnetic field gradient measuring device cannot be increased, and the magnetic field gradient measuring device in the embodiment of the application does not need to be additionally provided with a heat insulation device, so that the manufacturing cost of the magnetic field gradient measuring device can be reduced, and meanwhile, the structure in the embodiment is favorable for the miniaturization of the gas chamber structure.

In one embodiment, the laser processing module 10 is specifically configured to determine a first precession frequency of atoms in the first atom gas cell 201 according to the first intensity information, and determine a second precession frequency of atoms in the second atom gas cell 301 according to the second intensity information; and determining the magnetic field gradient of the magnetic field to be measured according to the first precession frequency, the second precession frequency, the gyromagnetic ratio of the atoms and the distance information between the first atom air chamber 201 and the second atom air chamber 301.

Because the first atom gas cell 201 and the second atom gas cell 301 are located at different positions of the magnetic field to be measured, there may be differences in the magnetic fields at the different positions, and therefore, under the action of different magnetic fields, the atoms in the first atom gas cell 201 and the second atom gas cell 301 have different precession frequencies of the atoms in the two atom gas cells.

Optionally, the laser processing module 10 may determine an intensity peak in the first intensity information according to the first intensity information, and determine a frequency corresponding to the intensity peak as a first precession frequency of the atom in the first atom gas cell 201; the laser processing module 10 may adjust the amplitude modulation frequency of the first optical signal according to the first intensity information sent by the first detector 203, so that when the amplitude modulation frequency of the first optical signal is the same as the precession frequency of the atom in the first atom gas chamber 201 under the action of the magnetic field to be detected, the intensity of the second optical signal detected by the first detector 203 reaches a peak value; when the laser processing module 10 determines an intensity peak value according to the first intensity information sent by the first detector 203, the amplitude modulation frequency of the first optical signal corresponding to the intensity peak value is the first precession frequency of the atom in the first atom gas chamber 201 under the magnetic field to be measured.

Similarly, the laser processing module 10 may determine an intensity peak in the second intensity information according to the second intensity information, and determine a frequency corresponding to the intensity peak as a second precession frequency of the atom in the second atom gas cell 301; the laser processing module 10 may adjust the amplitude modulation frequency of the first optical signal according to the second intensity information sent by the second detector 303, so that when the amplitude modulation frequency of the first optical signal is the same as the precession frequency of the atom in the second atom gas chamber 301 under the action of the magnetic field to be detected, the intensity of the third optical signal detected by the second detector 303 reaches a peak value; when the laser processing module 10 determines the intensity peak value according to the second intensity information sent by the second detector 303, the amplitude modulation frequency of the first optical signal corresponding to the intensity peak value is the second precession frequency of the atom in the second atom gas chamber 301 in the magnetic field to be measured.

After determining the first precession frequency of the atom in the first atom air chamber 201 under the magnetic field to be detected, the laser processing module 10 may determine, according to the ratio of the first precession frequency to the gyromagnetic ratio of the atom, a first magnetic field strength at the position of the first atom air chamber 201, and after determining the second precession frequency of the atom in the second atom air chamber 301 under the magnetic field to be detected, may determine, according to the ratio of the second precession frequency to the gyromagnetic ratio of the atom, a second magnetic field strength at the position of the second atom air chamber 301; further, the laser processing module 10 may determine the magnetic field gradient of the magnetic field to be measured according to the difference between the first magnetic field strength and the second magnetic field strength and the ratio of the distance between the first atomic gas chamber 201 and the second atomic gas chamber 301.

Optionally, the laser processing module 10 may further determine the magnetic field gradient of the magnetic field to be measured according to a difference between the first precession frequency and the second precession frequency, and a ratio between the gyromagnetic ratio of the atom and the distance information between the first atom gas cell 201 and the second atom gas cell 301.

In this embodiment, the laser processing module determines a first precession frequency of an atom in the first atom gas chamber according to the first intensity information, determines a second precession frequency of an atom in the second atom gas chamber according to the second intensity information, and determines a magnetic field gradient of the magnetic field to be measured according to the first precession frequency, the second precession frequency, a gyromagnetic ratio of the atom, and distance information between the first atom gas chamber and the second atom gas chamber; determining a first precession frequency of atoms in the first atomic gas chamber under the action of a magnetic field to be detected according to intensity information of first optical signals with different amplitude modulation frequencies and second optical signals after the first atomic gas chamber respectively acts on the first optical signals, and determining a second precession frequency of atoms in the second atomic gas chamber under the action of the magnetic field to be detected according to intensity information of first optical signals with different amplitude modulation frequencies and third optical signals after the second atomic gas chamber respectively acts on the first optical signals and the second optical signals; furthermore, the magnetic field gradient of the magnetic field to be measured is determined according to the first precession frequency, the second precession frequency, the gyromagnetic ratio of the atoms and the distance between the first atom gas chamber and the second atom gas chamber, and the calculation accuracy of the magnetic field gradient of the magnetic field to be measured can be improved.

In one embodiment, as shown in FIG. 2, the laser processing module 10 includes: a laser 101, a laser control module 102, and a laser beam splitter 103; a laser 101 for outputting a first optical signal whose own frequency coincides with a transition frequency of an atom; the laser control module 102 is configured to perform amplitude modulation on the first optical signal; and the laser beam splitter 103 is configured to perform beam splitting processing on the amplitude-modulated first optical signal, and input the first optical signal and the amplitude-modulated first optical signal to the first atomic gas cell 201 and the second atomic gas cell 301 respectively.

Alternatively, the frequency of the first optical signal output by the laser 101 may be determined according to the atom types of the first atom gas cell 201 and the second atom gas cell 301, that is, the frequency of the first optical signal output by the laser 101 is equal to the frequency of the atomic energy level transition, so that when the first optical signal acts on the first atom gas cell 201 and the second atom gas cell 301, the atoms in the first atom gas cell 201 and the second atom gas cell 301 can perform the energy level transition under the action of the first optical signal; optionally, in the embodiment of the present application, the atoms in the first atom gas cell 201 and the second atom gas cell 202 may be rubidium atoms, and the laser 101 may be a semiconductor laser.

After the laser 101 outputs the first optical signal, the laser control module 102 may perform amplitude modulation on the first optical signal through the laser control module 102, so that the first optical signal may intermittently act on the first atomic gas cell and the second atomic gas cell through different amplitude modulation frequencies; alternatively, the laser control module 102 may be a switch module having a switch characteristic, and the switch module may continuously perform the opening and closing operations under the control of a controller or a processor, so that the first optical signal may intermittently act on the first atomic gas cell and the second atomic gas cell.

After the laser control module 102 outputs the first optical signal after amplitude modulation, the first optical signal is subjected to beam splitting processing by the laser beam splitter 103, so that the first optical signal can be simultaneously input into the first atom gas cell 201 and the second atom gas cell 301, and further the first optical signal can interact with atoms in the first atom gas cell, and the first optical signal can also interact with atoms in the second atom gas cell. Alternatively, the laser beam splitter may be a polarizing beam splitter prism.

In this embodiment, the laser processing module includes a laser, a laser control module and a laser beam splitter, the laser outputs a first optical signal whose own frequency is consistent with the transition frequency of the atom, the laser control module performs amplitude modulation on the first optical signal, and the first optical signal and the second optical signal are respectively input to the first atom air chamber and the second atom air chamber after being split by the laser beam splitter; the function of the laser processing module is realized through the modularized structural design, the development difficulty of the laser processing module can be reduced, and the overall reliability of the laser processing module is improved.

In one embodiment, as shown in fig. 3, the laser processing module 10 further comprises: a laser transmission module 104; the laser transmission module 104 is configured to transmit the amplitude-modulated first optical signal output by the laser control module 102 to the laser beam splitter 103, so that the first optical signal is split by the laser beam splitter 103 and then is input to the first atom gas cell 201 and the second atom gas cell 301, respectively.

Alternatively, the laser transmission module 30 in this embodiment may be a polarization maintaining fiber, for example: single mode polarization maintaining fiber, multimode polarization maintaining fiber, etc.; in addition, the first optical signal may be linearly polarized light, and after the first optical signal passes through the polarization maintaining fiber, the polarization state of the first optical signal output by the polarization maintaining fiber and the polarization state of the first optical signal input to the polarization maintaining fiber can be kept consistent.

In this embodiment, through setting up laser transmission module for laser control module passes through laser transmission module and is connected with the laser beam splitter, can realize the separation of laser instrument and magnetic induction module, improves magnetic field gradient measuring device's design flexibility.

In one embodiment, as shown in FIG. 4, the laser processing module 10 further comprises a first fiber coupler 105 and a second fiber coupler 106, the first magnetic induction module 20 further comprises a first birefringent single crystal waveplate 204, and the second magnetic induction module 30 further comprises a second birefringent single crystal waveplate 304; a first optical fiber coupler 105 for coupling the first optical signal into the laser transmission module 104; a second optical fiber coupler 106, configured to collimate the first optical signal transmitted by the laser transmission module 104 and input the collimated first optical signal to the laser beam splitter 103; the first birefringent single crystal wave plate 204 is configured to adjust the polarization state of the first optical signal input to the first atomic gas chamber 201 by the laser beam splitter 103 into circularly polarized light, and input the circularly polarized light to the first atomic gas chamber 201; the second birefringent single crystal waveplate 304 is configured to adjust the polarization state of the first optical signal input to the second atomic gas cell 301 by the laser beam splitter 103 into circularly polarized light, and then input the circularly polarized light to the second atomic gas cell 301.

Specifically, the laser 101 outputs a first optical signal with a linearly polarized light, the first optical signal passes through the laser control module 102, is coupled into the first optical fiber coupler 105, is transmitted to the second optical fiber coupler 106 through the laser transmission module 104, is collimated by the second optical fiber coupler 106 and is output, the output first optical signal is split by the laser beam splitter 103, one of the output first optical signal passes through the first birefringent single crystal wave plate 204, converts the linear polarization state of the first optical signal into a circular polarization state, forms a circularly polarized light, is input into the first atomic gas chamber 201, is reflected by the first reflective mirror 202, passes through the first atomic gas chamber 201 again, then is re-converted into the linearly polarized light by the first birefringent single crystal wave plate 204, forms a second optical signal, and the intensity of the second optical signal is detected by the first detector 203; the other beam passes through the second birefringent single crystal wave plate 304, converts the linear polarization state of the first optical signal into a circular polarization state, forms circularly polarized light, is input into the second atom air chamber 301, is reflected by the second reflective mirror 302, passes through the second atom air chamber 301 again, then passes through the second birefringent single crystal wave plate 304 to convert the circularly polarized light into linearly polarized light again, forms a third optical signal, and is detected by the second detector 303 to detect the intensity of the third optical signal; alternatively, the first birefringent single-crystal wave plate 204 and the second birefringent single-crystal wave plate 304 may be λ/4 wave plates, such as: the quarter-wave plate can realize conversion between linearly polarized light and circularly polarized light.

In this embodiment, by adding the first optical fiber coupler, the second optical fiber coupler, the first birefringent single crystal wave plate and the second birefringent single crystal wave plate, a process that the laser outputs a single beam of linearly polarized light to act on two atomic air chambers to measure the magnetic field gradient can be realized, specifically, the transmission of the single beam of linearly polarized light is realized through the optical fiber coupler and the polarization maintaining optical fiber, and the polarization state of the linearly polarized light is changed through the birefringent single crystal wave plate, so that the optical signal acting on the atomic air chambers is circularly polarized light, and then the gradient of the magnetic field to be measured is determined through the intensity of the optical signal after the double action of the return optical path and the atomic air chambers, so that the diversity of the magnetic field gradient measuring device is increased.

In one embodiment, as shown in fig. 5, the laser processing module 10 further includes: a half wave plate 107; and a half wave plate 107 for adjusting the linear polarization state of the first optical signal output by the second fiber coupler 106.

Specifically, after the second fiber coupler 106 decouples the first optical signal, the first optical signal passes through the half-wave plate 107, the linear polarization state of the first optical signal can be adjusted, and then the adjusted first optical signal passes through the first birefringent single-crystal wave plate 204 and the second birefringent single-crystal wave plate 304 after being split by the laser beam splitter 103. Optionally, the half-wave plate 107 may also be located between the laser control module 102 and the first fiber coupler 105, that is, after the laser control module 102 outputs the first optical signal, the linear polarization state of the first optical signal is adjusted by the half-wave plate 107, so that the effect of circularly polarized light obtained after the first optical signal passes through the first birefringent single crystal wave plate 204 and the second birefringent single crystal wave plate 304 is better; it should be noted that the relative positions and angles between the half-wave plate 107 and the first and second birefringent single-crystal wave plates 204 and 304 can be properly adjusted according to the polarization state of the actual optical signal to obtain circularly polarized light.

In this embodiment, by adding the half-wave plate to the laser processing module, the polarization state of the output first optical signal can be adjusted, so that the effect of circularly polarized light obtained after the first optical signal passes through the birefringent single crystal wave plate is better, and the output effect of circularly polarized light can be improved.

In one embodiment, as shown in fig. 6, the laser processing module 10 further includes: a difference module 108; a difference module 108, configured to receive the first intensity information sent by the first detector 203 and the second intensity information sent by the second detector 303; the difference module 108 is further configured to send a difference result of the first intensity information and the second intensity information to the laser control module 102.

Specifically, the first detector 203 may input first intensity information of the second optical signal under the action of the detected first optical signal with different modulation frequencies into the differential module 108, and the second detector 303 may also input second intensity information of the third optical signal under the action of the detected first optical signal with different modulation frequencies into the differential module 108, where at the same time, the differential module 108 receives the intensity of the second optical signal and the intensity of the third optical signal under the action of the first optical signal with the same modulation frequency as the first intensity information and the second intensity information; optionally, the difference module 108 may be a difference amplifier, and after performing difference and amplification processing on the intensity of the second optical signal and the intensity of the third optical signal at the same modulation frequency, send the difference to the laser control module 102, so that the laser control module 102 determines the difference between the first precession frequency and the second precession frequency according to the difference result.

In this embodiment, the difference module is added to the laser processing module, so that the first detector inputs the acquired first intensity information and the acquired second intensity information of the second detector into the difference module, and after a difference result is obtained, the difference result is sent to the laser control module, thereby reducing the working pressure of the original integrated laser processing module and improving the processing efficiency of the laser processing module.

In one embodiment, as shown in fig. 7, the laser control module 102 includes a laser modulator 1021 and a control unit 1022; a control unit 1022, configured to control the laser modulator 1021 to output a modulation signal with different frequencies, where the modulation signal is used to perform amplitude modulation on the first optical signal.

Alternatively, the control unit 1022 may control the laser modulator 1021 to output a modulation signal with different frequencies, where the modulation signal may be a square wave signal or a sinusoidal signal, and the modulation signal may perform amplitude modulation on the first optical signal output by the laser 101, that is, implement a switching characteristic on the first optical signal, so that the first optical signal may be input to the first atomic gas cell 201 and the second atomic gas cell 301 at certain time intervals, and generate an intermittent action with both the first atomic gas cell 201 and the second atomic gas cell 301.

Optionally, the control unit 1022 is further configured to receive first intensity information of the second optical signal sent by the first detector 202 and second intensity information of the third optical signal sent by the second detector 302, and obtain an intensity peak of the first intensity information and an intensity peak of the second intensity information through analysis of the first intensity information and the second intensity information, respectively, so as to determine a first precession frequency corresponding to the intensity peak of the first intensity information and a second precession frequency corresponding to the intensity peak of the second intensity information.

Optionally, the control unit 1022 may further control the laser modulator 1021 to output modulation signals with different frequencies according to the first intensity information or the second intensity information, that is, the amplitude modulation frequency of the first optical signal may be adjusted according to a variation of the intensity of the second optical signal in the first intensity information with the amplitude modulation frequency of the first optical signal, so that the intensity of the second optical signal reaches a peak value, and further, the first precession frequency of the atom in the first atom gas cell is determined; the amplitude modulation frequency of the first optical signal can also be adjusted according to the variation condition of the intensity of the third optical signal in the second intensity information along with the amplitude modulation frequency of the first optical signal, so that the intensity of the third optical signal reaches a peak value, and further the second precession frequency of the atoms in the second atom gas chamber is determined.

In this embodiment, the laser control module is decomposed into the laser modulator and the control unit, the control unit controls the laser modulator to output modulation signals with different frequencies, the first optical signal is subjected to amplitude modulation through the modulation signals, and the laser control module is further refined, so that the integration level of the laser control module can be reduced, and the design flexibility of the laser control module is improved.

In one embodiment, as shown in fig. 8, an alternative implementation of the magnetic field gradient measuring apparatus includes: the laser comprises a laser, a laser modulator, a first optical fiber coupler, a polarization maintaining optical fiber, a second optical fiber coupler, a first half wave plate, a first polarization splitting prism, a first quarter wave plate, a first atom air chamber, a first reflective mirror, a first detector, a second half wave plate, a second polarization splitting prism, a second quarter wave plate, a second atom air chamber, a second reflective mirror, a second detector, a differential amplifier and a control unit.

Specifically, the laser outputs a first optical signal with the frequency consistent with the transition frequency of the atom, after the amplitude modulation is carried out by the laser modulator, the light is coupled into the optical fiber by the first optical fiber coupler, then transmitted to the second optical fiber coupler by the polarization maintaining optical fiber, collimated by the second optical fiber coupler and output to the first one-half wave plate for linear polarization state adjustment, then split by the first polarization splitting prism, and after beam splitting, one beam of the first optical signal is converted into circularly polarized light after passing through the first quarter-wave plate, passes through the first atom air chamber, returns through the first reflector, passes through the first atom air chamber again, after the first light signal is interacted with atoms in the first atom air chamber, the first light signal is converted into linearly polarized light through the first quarter-wave plate to form a second light signal, and after the second light signal passes through the first polarization beam splitting prism, the intensity of the second light signal is detected by the first detector; the other beam of the first optical signal is subjected to linear polarization state adjustment through a second half wave plate, then is subjected to laser reflection through a second polarization splitting prism, is converted into circularly polarized light after passing through a second quarter wave plate, passes through a second atom air chamber, returns through a second reflector, passes through the second atom air chamber again, is interacted with atoms in the second atom air chamber, is converted into linearly polarized light through the second quarter wave plate to form a third optical signal, and is subjected to second polarization splitting prism to detect the intensity of the third optical signal by a second detector; then, the first detector inputs the intensity of the detected second optical signal and the intensity of the third optical signal detected by the second detector into a differential amplifier for differential processing, and sends a differential result to a control unit, the control unit controls a laser modulator according to the differential result to adjust the amplitude modulation frequency of the first optical signal until a first precession frequency and a second precession frequency are respectively obtained, and then the gradient of the magnetic field to be measured is calculated according to the first precession frequency, the second precession frequency, the gyromagnetic ratio of atoms and the distance between the first atomic gas chamber and the second atomic gas chamber.

The magnetic field gradient measuring device in the embodiment has a simple structure, is easy to realize, can reduce the working temperature of the atomic gas chamber, reduces the cost of the magnetic field gradient measuring device, and improves the sensitivity and the accuracy of the magnetic field gradient measuring device.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.