Atomic magnetometer probe based on hyperpolarization nuclear spin measurement magnetic field and detection method

Abstract

The atomic magnetometer probe comprises a probe body, a cavity used for containing an alkali metal gas chamber is formed in one end of the probe body, 3He atoms and alkali metal are filled in the gas chamber, a pump light hole and a probe hole are formed in the two side walls of the cavity respectively, and the pump light hole and the probe hole correspond to each other in position. The rectangular prism corresponds to the pump light hole, the photoelectric detector corresponds to the detection hole, and radio frequency magnetic field biplanar coils are arranged on the upper surface and the lower surface of the cavity; a heating optical fiber hole and a pumping optical fiber hole are formed in the other end of the probe main body, one end of a pumping laser optical fiber is inserted into the pumping optical fiber hole, the other end of the pumping laser optical fiber is connected with a pumping laser, one end of a heating laser optical fiber is inserted into the heating optical fiber hole, and the other end of the heating laser optical fiber is connected with a heating laser; pump light emitted by the pump laser enters the rectangular prism through the first light path structure, and laser emitted by the heating laser enters the gas chamber through the second light path structure.

Description

Technical Field

[0001] The invention relates to the technical field of strong magnetic field measurement, and in particular to an atomic magnetometer probe and a detection method for measuring magnetic field based on hyperpolarized nuclear spins. Background Art

[0002] With the development of quantum science and technology, ultra-high sensitive atomic magnetometers based on hyperpolarized nuclear spins have been proposed and experimentally verified. Due to their excellent measurement sensitivity, anti-interference and ultra-high absolute magnetic field measurement accuracy, they are widely used in the field of strong magnetic field measurement and calibration. Moreover, since they do not require additional shielding of the geomagnetic field, they have unique advantages over other types of magnetometers and are currently an important development direction for atomic magnetometers in the field of strong magnetic field measurement. Since the magnetic field generated by the large current in the UHV transmission line is strong, the hyperpolarized nuclear spin magnetometer can be used to measure the current in the UHV transmission line.

[0003] At present, most optically pumped magnetometers are used for extremely weak magnetic field measurements and magnetic field measurements within the earth. Atomic magnetometers use lasers with specific wavelengths to polarize the spin direction of atoms to achieve precise measurement of magnetic fields. Most magnetometers are used in zero-field measurement scenarios and are sensitive to the weak magnetic field of the detector itself. Therefore, a magnetic field shielding system is required to shield the influence of the earth's magnetic field on the magnetometer. This also makes the magnetometer system unable to have the characteristics of miniaturization and portability, limiting its application in natural environments. For example, the patent application document with publication number CN116819407A proposes an atomic magnetometer system that uses 131 The Xe nuclear spin is used for weak magnetic field measurement, and the spatial structure complexity of the coil is simplified by using a double-plane coil as a residual magnetism compensation structure, thereby reducing the volume of the magnetic field measurement probe. However, since this scheme is for weak magnetic field measurement, it is sensitive to the magnetism of the photodetector itself, so the probe needs to be placed in a magnetic shielding barrel, and additional optical path elements need to be set up to change the optical path to arrange the photodetector away from the alkali metal atomic gas chamber. Therefore, the atomic magnetometer system designed in this scheme still cannot be miniaturized, and in the optically pumped probe structure, the measurement accuracy is highest in the optical pumping direction, but due to the presence of various optical elements, the size in the pumping direction cannot be further reduced, resulting in the application scenario not being suitable for magnetic field measurement in small spaces.

[0004] In contrast, using hyperpolarized 3 The measurement of He nuclear spin in strong magnetic field (above 0.01T) is a new type of optically pumped magnetometer, and its structural design is the basis of the magnetometer. 3He nuclear spin magnetometers do not need to shield the earth's magnetic field when working, and can read output signals by modulating and demodulating the magnetic field through specific coils, which has the potential for miniaturization and portability. In particular, they can be used in strong magnetic fields, and can be used to measure the magnetic field generated by superconducting magnets, the magnetic field generated by ultra-high voltage transmission lines, and the magnetic field generated by large currents of hydro-turbine generators.

[0005] The core unit of the optically pumped hyperpolarized magnetometer is the measuring probe, which needs to have the characteristics of miniaturization and simple structure. Therefore, it is urgent to design an atomic magnetometer probe structure based on hyperpolarized nuclear spin measurement of magnetic field, which has the ability to work in an open environment and its size is further reduced compared to existing structures. Summary of the invention

[0006] The technical problem to be solved by the present invention is how to significantly reduce the size of the magnetic field probe of the quantum current sensor.

[0007] The present invention solves the above technical problems by the following technical means:

[0008] The present invention proposes an atomic magnetometer probe for measuring magnetic field based on hyperpolarized nuclear spin, comprising a probe body, one end of which is provided with a cavity for accommodating an alkali metal gas chamber, the alkali metal gas chamber being filled with 3 He atoms and alkali metals, the two side walls of the cavity are respectively provided with corresponding pump light holes and detection holes, the right angle prism is arranged corresponding to the pump light holes, the photodetector is arranged corresponding to the detection holes, and the upper and lower surfaces of the cavity are both provided with radio frequency magnetic field double plane coils;

[0009] A heating fiber hole and a pump fiber hole are provided at the other end of the probe body, one end of the pump laser fiber is inserted into the pump fiber hole, and the other end of the pump laser fiber is connected to the pump laser, one end of the heating laser fiber is inserted into the heating fiber hole, and the other end of the heating laser fiber is connected to the heating laser; the pump light emitted by the pump laser is incident on the right-angle prism through the first optical path structure, and the laser light emitted by the heating laser is incident on the alkali metal gas chamber through the second optical path structure.

[0010] Further, the first optical path structure includes a λ / 2 wave plate, a polarization beam splitter prism and a first optical fiber coupler in a coaxial state, the first optical fiber coupler is connected to a second optical fiber coupler via an optical fiber, an optical lens is arranged on the outgoing light path of the second optical fiber coupler, and a λ / 4 wave plate is arranged on the outgoing light path of the optical lens;

[0011] The outgoing light of the λ / 4 wave plate is incident on the right-angle prism, the pump light hole and the detection hole and propagates to the photodetector.

[0012] Furthermore, the second optical path structure includes a third fiber coupler and a fourth fiber coupler connected via optical fibers, the third fiber coupler is arranged on the output light path of the heating laser, and the output light of the fourth fiber coupler propagates to the alkali metal gas chamber.

[0013] Furthermore, the probe body is also provided with an optical lens hole bracket, a λ / 4 wave plate hole bracket and a prism base, the optical lens is arranged on the optical lens hole bracket, the λ / 4 wave plate is arranged on the λ / 4 wave plate hole bracket, and the right-angle prism is arranged on the prism base.

[0014] Furthermore, an air chamber fixing hole is arranged in the cavity, and the alkali metal air chamber is installed in the air chamber fixing hole.

[0015] Furthermore, the cavity is a thermal insulation chamber, and an air chamber cover is provided on the thermal insulation chamber.

[0016] Furthermore, a temperature sensor is arranged on the air chamber cover plate.

[0017] Furthermore, the probe is formed by 3D printing, and the material is PEEK plastic.

[0018] In addition, the present invention also proposes a method for performing strong magnetic field detection using the atomic magnetometer probe based on hyperpolarized nuclear spin magnetic field measurement as described above, the method comprising:

[0019] The output pulse time of the radio frequency amplifier is controlled by the host computer to generate a radio frequency pulse signal of variable length to be loaded into the radio frequency magnetic field double plane coil, so that the radio frequency magnetic field double plane coil controls the nuclear power in the alkali metal gas chamber. 3 The spin of the He atom deviates from the direction of the magnetic field to be measured by a certain angle, and the nuclear spin magnetic moment produces a magnetic field signal with a precession frequency;

[0020] Processing the free induction decay signal of the magnetic field signal to obtain a processed free induction decay signal;

[0021] The processed free induction decay signal is digitized and stored in the host computer.

[0022] Furthermore, the control of the output pulse time of the radio frequency amplifier by the host computer to generate a radio frequency pulse signal of variable length to be loaded to the radio frequency magnetic field double-plane coil includes:

[0023] Apply a radio frequency field with a frequency of ω0 to the magnetic field to be measured Set the time t so that the magnetic moment Rotated around the z-axis to an angle α, where the RF field Perpendicular to the magnetic field to be measured, the relationship between the nuclear spin pointing angle α and the pulse duration t is:

[0024] t=α / γB1

[0025] Where γ is the rotating magnetic ratio, B1 is the RF pulse magnetic field The amplitude of .

[0026] Furthermore, the processing of the free induction decay signal of the magnetic field signal to obtain a processed free induction decay signal includes:

[0027] The free induction decay signal is extracted, amplified, and denoised to obtain a processed free induction decay signal.

[0028] The advantages of the present invention are:

[0029] (1) The conventional optically pumped magnetometer probe needs to set up additional optical path elements to change the optical path and arrange the photodetector away from the alkali metal atom gas chamber. Due to the presence of various optical components, the size of the probe cannot be reduced along the pump light direction, resulting in the application scenario being not suitable for magnetic field measurement in a small space. The present invention further optimizes various optical elements while ensuring the specific polarization state and spot size of the pump laser. By changing the optical path structure, such as designing and adding a right-angle prism to change the propagation direction of the pump light, rearranging the polarization element, heating the placement of the laser fiber, etc., and reducing a right-angle prism optical component, the size of the probe in the pump light direction is further compressed, so that the size of the improved probe in the pump polarization direction is reduced by more than 2 times compared with the conventional probe.

[0030] (2) The present invention uses a dual-plane coil to control the spatial angle of the nuclear spin and extract the precession signal of the nuclear spin. The pickup coil picks up the electric field signal and then processes and reads the magnetic field information to be measured. The optical detector is used to monitor the laser power fluctuation of the pump laser, thereby reducing the error introduced by the optical signal fluctuation and removing the limitation that the probe needs a shielding tube, thereby further expanding the application scenarios of the probe.

[0031] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of an atomic magnetometer probe for measuring magnetic field based on hyperpolarized nuclear spins proposed in one embodiment of the present invention;

[0033] Figure 2 It is a schematic diagram of the main structure of an atomic magnetometer probe in one embodiment of the present invention;

[0034] Figure 3 is a schematic diagram of the optical path of an atomic magnetometer probe in one embodiment of the present invention;

[0035] Figure 4 is a schematic diagram of signal acquisition of an atomic magnetometer probe in one embodiment of the present invention;

[0036] Figure 5 The present invention is a flowchart of an embodiment of the present invention, which is based on the atomic magnetometer probe for measuring the magnetic field of hyperpolarized nuclear spins to perform strong magnetic field detection.

[0037] In the figure:

[0038] 1-heating laser fiber, 2-pumping laser fiber, 3-photodetector, 4-double plane coil, 5-air chamber cover, 6-probe body, 7-heating fiber hole, 8-pumping fiber hole, 9-optical lens hole bracket, 10-λ / 4 wave plate hole bracket, 11-prism base, 12-pumping light hole, 13-cover buckle, 14-air chamber fixing hole, 15-detection hole, 16-host computer, 17-data transceiver system board, 18-cavity, 19-alkali metal air chamber, 20-right angle prism, 21-first fiber coupler, 22-polarization beam splitter prism, 23-λ / 2 wave plate, 24-pumping laser, 25-heating laser, 26-third fiber coupler, 27-λ / 4 wave plate, 28-optical lens, 29-second fiber coupler, 30-fourth fiber coupler. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] like Figure 1 to Figure 2 As shown, the first embodiment of the present invention proposes an atomic magnetometer probe for measuring magnetic field based on hyperpolarized nuclear spin, which includes a probe body 6, and a cavity 18 for accommodating an alkali metal gas chamber 19 is opened at one end of the probe body 6, and the alkali metal gas chamber 19 is filled with 3 He atoms and alkali metal atoms, the two side walls of the cavity 18 are respectively provided with corresponding pump light holes 12 and detection holes 15, the right angle prism 20 is arranged corresponding to the pump light holes 12, the photodetector 3 is arranged corresponding to the detection holes 15, and the upper and lower surfaces of the cavity 18 are both provided with radio frequency magnetic field double plane coils 4;

[0041] A heating fiber hole 7 and a pumping fiber hole 8 are provided at the other end of the probe body 6, one end of the pumping laser fiber 2 is inserted into the pumping fiber hole 8, and the other end of the pumping laser fiber 2 is connected to the pumping laser 24, one end of the heating laser fiber 1 is inserted into the heating fiber hole 7, and the other end of the heating laser fiber 1 is connected to the heating laser 25; the pumping light emitted by the pumping laser 24 is incident on the right-angle prism 20 through the first optical path structure, and the laser light emitted by the heating laser 25 is incident on the alkali metal gas chamber 19 through the second optical path structure.

[0042] It should be noted that, in this embodiment, a radio frequency magnetic field double-plane coil 4 is arranged on the upper and lower surfaces of the alkali metal gas chamber 19, and a pulse magnetic field is applied to the radio frequency magnetic field double-plane coil 4 to excite 3 The He nuclear spin deviates from the direction of the strong magnetic field to be measured, and the electric field signal is picked up and processed to read the information of the strong magnetic field to be measured. Since the current generated in the coil is detected, it is not sensitive to the weak current of the photodetector 3. Therefore, there is no need to put the probe into the magnetic shielding barrel, and there is no need to set up additional optical path elements to change the optical path to arrange the photodetector 3 away from the alkali metal atom gas chamber; therefore, this embodiment can further optimize various optical elements under the premise of ensuring the specific polarization state and spot size of the pump laser, and change the propagation direction of the pump light, rearrange the polarization element, heat the placement of the laser fiber 1, etc. by changing the optical path structure, such as designing and adding a right-angle prism 20 to change the direction of pump light propagation, rearrange the polarization element, and reduce the placement of a right-angle prism 20 optical components to further compress the size of the probe light in the pumping direction, so that the size of the improved probe in the pump polarization direction is reduced by more than 2 times compared with the traditional probe.

[0043] As a further preferred technical solution, Figure 3 to Figure 4 As shown, the first optical path structure includes a λ / 2 wave plate 23 in a coaxial state, a polarization beam splitter prism 22 and a first fiber coupler 21, the first fiber coupler 21 is connected to a second fiber coupler 29 via an optical fiber, an optical lens 28 is arranged on the outgoing light path of the second fiber coupler 29, and a λ / 4 wave plate 27 is arranged on the outgoing light path of the optical lens 28;

[0044] The outgoing light of the λ / 4 wave plate 27 is incident on the right-angle prism 20 and propagates through the pump light hole 12 and the detection hole 15 to the photodetector 3 .

[0045] Specifically, the pump laser 24 emits a laser of corresponding wavelength, and adjusts the laser power and polarization state through the λ / 2 wave plate 23 and the polarization splitter prism 22 in turn. Then, the laser is loaded onto the probe through the first fiber coupler 21 and the second fiber coupler 29. The beam size and circular polarization state of the pump laser are adjusted through the optical lens 28 and the λ / 2 wave plate 23 on the probe. Then, the pump laser changes its propagation direction through the right-angle prism 20 and is incident on the alkali metal gas chamber 19 to polarize the 3He atoms. The transmitted pump light detects the laser power fluctuation through the photodetector 3.

[0046] As a further preferred technical solution, Figure 3 to Figure 4 As shown, the second optical path structure includes a third fiber coupler 26 and a fourth fiber coupler 30 connected via optical fibers. The third fiber coupler 26 is arranged on the outgoing light path of the heating laser 25 , and the outgoing light of the fourth fiber coupler 30 propagates to the alkali metal gas chamber 19 .

[0047] Specifically, the heating laser 25 injects the heating laser into the alkali metal gas chamber 19 through the third fiber coupler 26 and the fourth fiber coupler 30, so that the alkali metal gas chamber 19 reaches the required working temperature. Compared with the traditional heat convection conduction heating, the present embodiment adopts the laser heating gas chamber, which reduces the complexity of the system and only needs to add a deep hole corresponding to the size of the heating fiber on the probe.

[0048] As a further preferred technical solution, the probe body 6 is also provided with an optical lens 28 hole bracket 9, a λ / 4 wave plate 27 hole bracket 10 and a prism base 11, the optical lens 28 is arranged on the optical lens 28 hole bracket 9, the λ / 4 wave plate 27 is arranged on the λ / 4 wave plate 27 hole bracket 10, and the right-angle prism 20 is arranged on the prism base 11.

[0049] As a further preferred technical solution, an air chamber fixing hole 14 is arranged in the cavity 18 , and the alkali metal air chamber 19 is installed in the air chamber fixing hole 14 .

[0050] In this embodiment, two apertures are designed on the probe body 6 located below the right-angle prism 20 to fix the wave plate and the optical lens 28 to adjust and maintain the polarization state of the pump light, and the diameter of the pump light spot can be adjusted by replacing the optical lens 28 with different focal lengths.

[0051] Specifically, in this embodiment, one end of the heating laser fiber 1 is connected to the heating laser 25, and the other end is inserted into the heating fiber hole 7. Similarly, one end of the pump laser fiber 2 is connected to the pump laser 24, and the other end is inserted into the pump fiber hole 8. The designed aperture corresponds to the fiber diameter. The photodetector 3 is installed near the pump light hole 12, and the pump light is incident on the photodetector 3 through the light hole to realize real-time monitoring of the pump light power. Then, the optical lens 28 and the λ / 4 wave plate 27 are installed on the corresponding optical lens 28 hole bracket 9 and the λ / 4 wave plate 27 hole bracket 10. The polarization axis of the pump light can be adjusted by rotating the wave plate, so that the angle between the polarization axis of the pump light and the fast axis or slow axis of the glass slide is 45 degrees. The optical lens 28 with different focal lengths can be replaced to control the pump light spot diameter. The right-angle prism 20 can be fixed to the prism base 11 by gel to change the pump light propagation path. The alkali metal gas chamber 19 is installed on the gas chamber fixing hole 14, and its position is adjusted so that the pump light is incident on the central area of ​​the gas chamber, and then fixed by gel. Finally, the gas chamber cover 5 is snapped onto the cover buckle 13 to seal the gas chamber space and reduce the temperature loss in the gas chamber area.

[0052] In actual use, the atomic magnetometer probe is set in the strong magnetic environment to be measured for high-resolution measurement of strong magnetic fields. Double-plane coils 4 are installed at the front and back of the gas chamber to control the nuclear spin so that the nuclear spin deviates from the direction of the magnetic field to be measured by a certain angle. The nuclear spin will precess in the external magnetic field, and the nuclear spin magnetic moment will generate a magnetic field signal of the precession frequency. Then the double-plane coil 4 will also take into account the function of the pickup coil to measure the nuclear spin precession signal; the data transceiver system board 17 connects the double-plane coil 4 on the probe to the data processing system outside the strong magnetic field environment through a data line, and measures the precession frequency by demodulating the signal. The upper computer 16 is controlled to realize the measurement of the magnetic field size of the strong magnetic environment, and the magnetic field gradient measurement is realized by moving the probe.

[0053] In this embodiment, the electric field signal is picked up by the pickup coil and then processed to read the magnetic field information to be measured, and the laser power fluctuation of the pump laser 24 is monitored by the photodetector 3, thereby reducing the error introduced by the optical signal fluctuation. Therefore, the magnetism of the photodetector 3 itself does not affect the measurement accuracy, and the limitation of the shielding barrel required for the probe can be removed. There is no need for additional optical path elements to change the optical path to move the photodetector 3 away from the air chamber, which can greatly reduce the size of the probe. In addition, by integrating the heating laser, pump laser, and radio frequency magnetic field double-plane coil 4, the polarized atoms are pumped to achieve hyperpolarization of the nuclear spin. Without affecting the magnetic field measurement accuracy of the magnetometer, the probe size is further reduced, so that the application scenarios of the probe are further expanded.

[0054] As a further preferred technical solution, the cavity 18 is a thermal insulation chamber, and an air chamber cover plate 5 is provided on the thermal insulation chamber.

[0055] It should be noted that after the air chamber is installed, the cover plate above the air chamber seals the cavity 18 where the air chamber is located through the buckle designed on the probe, thereby improving the thermal insulation of the air chamber cavity 18. Subsequently, a temperature sensor can still be placed on the cover plate to realize real-time monitoring of the air chamber temperature.

[0056] As a further preferred technical solution, the probe is formed by 3D printing, and the material is PEEK plastic.

[0057] It should be noted that the overall structure of the probe is formed through 3D printing and the material is PEEK plastic, which greatly improves the temperature resistance and structural strength of the probe.

[0058] In addition, if Figure 5 As shown, the second embodiment of the present invention proposes a method for performing strong magnetic field detection using the atomic magnetometer probe based on hyperpolarized nuclear spin measurement magnetic field described in the first embodiment, the method comprising the following steps:

[0059] S10, controlling the output pulse time of the radio frequency amplifier by the host computer to generate a radio frequency pulse signal of variable length to be loaded into the radio frequency magnetic field double plane coil, so that the radio frequency magnetic field double plane coil controls the nuclear power in the alkali metal gas chamber 3 The spin of the He atom deviates from the direction of the magnetic field to be measured by a certain angle, and the nuclear spin magnetic moment produces a magnetic field signal with a precession frequency;

[0060] S20, processing the free induction decay signal of the magnetic field signal to obtain a processed free induction decay signal;

[0061] S30, digitizing the processed free induction decay signal and storing it in the host computer.

[0062] In this embodiment, the atomic magnetometer probe is set in the strong magnetic environment to be measured for high-resolution measurement of strong magnetic fields. Double-plane coils are installed at the front and back of the gas chamber to control the nuclear spin so that the nuclear spin deviates from the direction of the magnetic field to be measured by a certain angle. The nuclear spin will precess in the external magnetic field, and the nuclear spin magnetic moment will generate a magnetic field signal with a precession frequency. Then the double-plane coil also takes on the function of a pickup coil to measure the nuclear spin precession signal. The measurement of the magnetic field size in the strong magnetic environment is achieved through the control of the host computer, and the magnetic field gradient measurement is achieved by moving the probe.

[0063] As a further preferred technical solution, the step S10: controlling the output pulse time of the radio frequency amplifier by the host computer to generate a radio frequency pulse signal of variable length to be loaded to the radio frequency magnetic field double-plane coil includes:

[0064] Apply a radio frequency field with a frequency of ω0 to the magnetic field to be measured Set the time t so that the magnetic moment Rotated around the z-axis to an angle α, where the RF field Perpendicular to the magnetic field to be measured, the relationship between the duration t of the radio frequency pulse signal and the nuclear spin deviation angle α is:

[0065] t=α / γB1

[0066] Where γ is the rotating magnetic ratio, B1 is the RF pulse magnetic field The amplitude of .

[0067] For example, when the rotation angle is π / 2, the required pulse signal duration t 1 / 2 for:

[0068]

[0069] After rotating the precession into the transverse plane using such a π / 2 pulse, the induced current can be picked up from the precession using a pick-up coil. The signal from the coil is called the free induction decay (FID) signal, providing a measure of the B0 magnetic field.

[0070] As a further preferred technical solution, the free induction decay signal of the magnetic field signal is processed to obtain a processed free induction decay signal, including:

[0071] The free induction decay signal is extracted, amplified, and denoised to obtain a processed free induction decay signal.

[0072] Specifically, in this embodiment, a signal processing module may be used to process the free induction decay signal. The signal processing module includes a bandpass filter, an amplifier, a mixer and a preamplifier connected in sequence.

[0073] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0074] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0075] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An atomic magnetometer probe for measuring magnetic fields based on hyperpolarized nuclear spins, characterized in that: The probe body comprises a probe body, wherein one end of the probe body is provided with a cavity for accommodating an alkali metal gas chamber, wherein the alkali metal gas chamber is filled with 3 He atoms and alkali metals, the two side walls of the cavity are respectively provided with corresponding pump light holes and detection holes, the right angle prism is arranged corresponding to the pump light holes, the photodetector is arranged corresponding to the detection holes, and the upper and lower surfaces of the cavity are both provided with radio frequency magnetic field double plane coils; A heating fiber hole and a pump fiber hole are provided at the other end of the probe body, one end of the pump laser fiber is inserted into the pump fiber hole, and the other end of the pump laser fiber is connected to the pump laser, one end of the heating laser fiber is inserted into the heating fiber hole, and the other end of the heating laser fiber is connected to the heating laser; the pump light emitted by the pump laser is incident on the right-angle prism through the first optical path structure, and the laser light emitted by the heating laser is incident on the alkali metal gas chamber through the second optical path structure.

2. The atomic magnetometer probe for measuring magnetic field based on hyperpolarized nuclear spins according to claim 1, characterized in that: The first optical path structure includes a λ / 2 wave plate, a polarization beam splitter prism and a first optical fiber coupler in a coaxial state, the first optical fiber coupler is connected to a second optical fiber coupler via an optical fiber, an optical lens is arranged on the outgoing light path of the second optical fiber coupler, and a λ / 4 wave plate is arranged on the outgoing light path of the optical lens; The outgoing light of the λ / 4 wave plate is incident on the pump light hole and the detection hole through the right-angle prism and propagates to the photodetector.

3. The atomic magnetometer probe for measuring magnetic field based on hyperpolarized nuclear spins according to claim 1, characterized in that: The second optical path structure includes a third optical fiber coupler and a fourth optical fiber coupler connected via optical fibers. The third optical fiber coupler is arranged on the outgoing light path of the heating laser, and the outgoing light of the fourth optical fiber coupler propagates to the alkali metal gas chamber.

4. The atomic magnetometer probe for measuring magnetic field based on hyperpolarized nuclear spins as claimed in claim 2, characterized in that: The probe body is also provided with an optical lens hole bracket, a λ / 4 wave plate hole bracket and a prism base, the optical lens is arranged on the optical lens hole bracket, the λ / 4 wave plate is arranged on the λ / 4 wave plate hole bracket, and the right-angle prism is arranged on the prism base.

5. The atomic magnetometer probe for measuring magnetic field based on hyperpolarized nuclear spins according to claim 1, characterized in that: An air chamber fixing hole is arranged in the cavity, and the alkali metal air chamber is installed in the air chamber fixing hole.

6. The atomic magnetometer probe for measuring magnetic field based on hyperpolarized nuclear spins according to claim 1, characterized in that: The cavity is a heat-insulating chamber, and an air chamber cover is arranged on the heat-insulating chamber.

7. The atomic magnetometer probe for measuring magnetic field based on hyperpolarized nuclear spins according to claim 6, characterized in that: A temperature sensor is arranged on the air chamber cover plate.

8. The atomic magnetometer probe for measuring magnetic field based on hyperpolarized nuclear spins according to any one of claims 1 to 7, characterized in that: The probe is formed by 3D printing and is made of PEEK plastic.

9. A method for strong magnetic field detection using the atomic magnetometer probe based on hyperpolarized nuclear spin measurement magnetic field according to any one of claims 1 to 8, characterized in that: The method comprises: The output pulse time of the radio frequency amplifier is controlled by the host computer to generate a radio frequency pulse signal of variable length to be loaded into the radio frequency magnetic field double plane coil, so that the radio frequency magnetic field double plane coil controls the nuclear power in the alkali metal gas chamber. 3 The spin of the He atom deviates from the direction of the magnetic field to be measured by a certain angle, and the nuclear spin magnetic moment produces a magnetic field signal with a precession frequency; Processing the free induction decay signal of the magnetic field signal to obtain a processed free induction decay signal; The processed free induction decay signal is digitized and stored in the host computer.

10. The method for strong magnetic field detection using an atomic magnetometer probe based on hyperpolarized nuclear spin magnetic field measurement according to claim 9, characterized in that: The output pulse time of the radio frequency amplifier is controlled by the host computer to generate a radio frequency pulse signal of variable length to be loaded to the radio frequency magnetic field double-plane coil, including: Apply a radio frequency field with a frequency of ω0 to the magnetic field to be measured Set the time t so that the magnetic moment Rotated around the z-axis to an angle α, where the RF field Perpendicular to the magnetic field to be measured, the relationship between the nuclear spin pointing angle α and the pulse duration t is: t=α / γB1 Where γ is the rotating magnetic ratio, B1 is the RF pulse magnetic field The amplitude of .

11. The method for strong magnetic field detection using an atomic magnetometer probe based on hyperpolarized nuclear spin magnetic field measurement according to claim 9, characterized in that: The step of processing the free induction decay signal of the magnetic field signal to obtain a processed free induction decay signal comprises: The free induction decay signal is extracted, amplified, and denoised to obtain a processed free induction decay signal.

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