Magnetic field measurement method, system, storage medium and electronic device

Abstract

The present invention relates to the field of magnetic field measurement technology, and in particular to a magnetic field measurement method, system, storage medium and electronic equipment. Left-handed circularly polarized light and right-handed circularly polarized light are used to control atomic quantum states and generate quantum interference effects in atomic Zeeman magneton energy levels, namely, electromagnetically induced absorption and electromagnetically induced transparency. The second transmitted light of the left-handed circularly polarized light changes with the angle between the light and the magnetic field direction, thereby measuring the magnitude of the external magnetic field while providing information on its direction. Calculations show that the light transmission peak line width (full width at half maximum) of the electromagnetically induced absorption can reach 0.6 of the Zeeman magneton energy level interval frequency, which also provides extremely high magnetic field measurement sensitivity.

Description

Technical Field

[0001] The present invention relates to the field of magnetic field measurement technology, and in particular to a magnetic field measurement method, system, storage medium and electronic equipment. Background Art

[0002] Optically pumped magnetic resonance is also a magnetic field measurement technique. This technique uses a beam of circularly polarized light to prepare atoms to a specific magnon energy level. A radio frequency field is then used to uniformly distribute the atomic population across the magnon energy levels. When the frequency difference between the RF field and the magnon energy levels is the same, the RF field can maximize the transfer of atomic population to other magnon energy levels. The circularly polarized light then continues to pump the atoms to an excited state, returning them to the ground state through spontaneous radiation, where the population accumulates again at a specific magnon energy level. During this dynamic process, when the frequency difference between the RF field and the magnon energy levels is the same, the pump light is absorbed the most, and the light detector observes the weakest transmitted light signal, which can also be used to indicate the magnitude of the magnetic field. Optically pumped magnetic resonance technology generally only provides information on the magnitude of the magnetic field and cannot directly determine its direction. The optical transmission absorption peak signal of optically pumped magnetic resonance also has a large linewidth, which limits its sensitivity. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the deficiencies of the existing technology and provide a magnetic field measurement method, system, storage medium and electronic equipment.

[0004] The technical solution of a magnetic field measurement method of the present invention is as follows:

[0005] Presetting the frequency of the left-handed circularly polarized light and the frequency of the right-handed circularly polarized light so that the left-handed circularly polarized light and the right-handed circularly polarized light are coupled to the ground state and excited state Zeeman magneton energy levels of the alkali metal atoms placed in the gas cell;

[0006] Simultaneously adjusting the frequency of the left-handed circularly polarized light and the frequency of the right-handed circularly polarized light to produce electromagnetically induced absorption;

[0007] determining a magnetic sub-level spacing frequency of the alkali metal atom according to first transmitted light of the left-handed circularly polarized light and the right-handed circularly polarized light passing through the gas cell;

[0008] Calculating the magnitude of the magnetic field at the location of the gas chamber according to the magnetic sub-energy level interval frequency of the alkali metal atoms;

[0009] The frequency of the right-handed circularly polarized light is set at a fixed frequency, the magnitude of the fixed frequency being equal to the transmission frequency between the g2 energy level of the ground state and the e2 energy level of the excited state of the alkali metal atom, wherein the transmission frequency is calculated based on the magnitude of the magnetic field, and the frequency of the left-handed circularly polarized light is adjusted so that the right-handed circularly polarized light produces electromagnetically induced transparency and the left-handed circularly polarized light produces electromagnetically induced absorption;

[0010] The direction of the magnetic field at the location of the air cell is determined according to the second transmitted light of the left-handed circularly polarized light passing through the air cell.

[0011] The beneficial effects of a magnetic field measurement method of the present invention are as follows:

[0012] Left-handed circularly polarized light and right-handed circularly polarized light are used to control the atomic quantum state and produce quantum interference effects in the atomic Zeeman magneton energy levels, namely the electromagnetically induced absorption phenomenon and the electromagnetically induced transparency phenomenon. The second transmitted light of the left-handed circularly polarized light will change with the angle between it and the direction of the magnetic field. In this way, the magnitude of the external magnetic field can be measured while providing information on the direction of the external magnetic field. Calculations show that the light transmission peak line width (full width at half maximum) of the electromagnetically induced absorption can reach 0.6 of the Zeeman magneton energy level interval frequency, which will also provide extremely high magnetic field measurement sensitivity.

[0013] The technical solution of a magnetic field measurement system of the present invention is as follows:

[0014] It includes a presetting module, a first adjusting module, a first determining module, a calculating module, a second adjusting module and a second determining module;

[0015] The presetting module is used to preset the frequency of left-handed circularly polarized light and the frequency of right-handed circularly polarized light so that the left-handed circularly polarized light and the right-handed circularly polarized light are coupled to the ground state and excited state Zeeman magneton energy levels of the alkali metal atoms placed in the gas cell;

[0016] The first adjustment module is used to: simultaneously adjust the frequency of the left-handed circularly polarized light and the frequency of the right-handed circularly polarized light to generate electromagnetic induced absorption;

[0017] The first determining module is configured to determine the magnetic sub-level interval frequency of the alkali metal atom according to the first transmitted light of the left-handed circularly polarized light and the right-handed circularly polarized light passing through the gas cell;

[0018] The calculation module is used to calculate the magnitude of the magnetic field at the location of the gas chamber according to the magnetic sub-level interval frequency of the alkali metal atoms;

[0019] The second adjustment module is used to: set the frequency of the right-handed circularly polarized light at a fixed frequency, the fixed frequency being equal to the transmission frequency between the g2 energy level of the ground state and the e2 energy level of the excited state of the alkali metal atom, wherein the transmission frequency is calculated according to the magnitude of the magnetic field, and the frequency of the left-handed circularly polarized light is adjusted to cause the right-handed circularly polarized light to produce electromagnetically induced transparency and the left-handed circularly polarized light to produce electromagnetically induced absorption;

[0020] The second determining module is configured to determine the direction of the magnetic field at the location of the air cell according to the second transmitted light of the left-handed circularly polarized light passing through the air cell.

[0021] The beneficial effects of a magnetic field measurement system of the present invention are as follows:

[0022] Left-handed circularly polarized light and right-handed circularly polarized light are used to control the atomic quantum state and produce quantum interference effects in the atomic Zeeman magneton energy levels, namely the electromagnetically induced absorption phenomenon and the electromagnetically induced transparency phenomenon. The second transmitted light of the left-handed circularly polarized light will change with the angle between it and the direction of the magnetic field. In this way, the magnitude of the external magnetic field can be measured while providing information on the direction of the external magnetic field. Calculations show that the light transmission peak line width (full width at half maximum) of the electromagnetically induced absorption can reach 0.6 of the Zeeman magneton energy level interval frequency, which will also provide extremely high magnetic field measurement sensitivity.

[0023] A storage medium of the present invention stores instructions, and when a computer reads the instructions, the computer executes any one of the above-mentioned magnetic field measurement methods.

[0024] An electronic device of the present invention includes a processor and the above-mentioned storage medium, wherein the processor executes instructions in the storage medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic flow chart of a magnetic field measurement method according to an embodiment of the present invention;

[0026] Figure 2 Schematic diagram of the interaction between light and magnetic field and atomic gas in the atomic gas chamber;

[0027] Figure 3 Schematic diagram of the interaction between rubidium atoms and circularly polarized light;

[0028] Figure 4 One of the schematic diagrams of the absorption curves of GLPC and GRPC;

[0029] Figure 5 The second schematic diagram of the absorption curves of GLPC and GRPC;

[0030] Figure 6The third schematic diagram of the absorption curves of GLPC and GRPC;

[0031] Figure 7 The fourth schematic diagram of the absorption curves of GLPC and GRPC;

[0032] Figure 8 The fifth schematic diagram of the absorption curves of GLPC and GRPC;

[0033] Figure 9 Schematic diagram 6 of the absorption curves of GLPC and GRPC;

[0034] Figure 10 This is the system device diagram;

[0035] Figure 11 This is a diagram showing the principle of interaction between left-handed polarized light and right-handed circularly polarized light and the energy levels of rubidium 87 atoms;

[0036] Figure 12 Schematic diagram of the structure of a magnetic field measurement system according to an embodiment of the present invention; DETAILED DESCRIPTION

[0037] like Figure 1 As shown, a magnetic field measurement method according to an embodiment of the present invention includes the following steps:

[0038] S1. Presetting the frequency of left-handed circularly polarized light and the frequency of right-handed circularly polarized light so that the left-handed circularly polarized light and the right-handed circularly polarized light are coupled to the ground state and excited state Zeeman magneton energy levels of the alkali metal atoms placed in the gas cell;

[0039] The alkali metal atom is a rubidium atom or a cesium atom. The alkali metal atom is described by taking the alkali metal rubidium 87 atom as an example. The ground state of the rubidium 87 atom is 87 R5S 1 / 2 F=2 energy level, the excited state of rubidium 87 atom is: 5P 1 / 2 F'=1 energy level, let the transition frequency from the ground state g3 energy level to the excited state e2 energy level be Initially, the frequency ω1 of the left-handed circularly polarized light and the frequency ω2 of the right-handed circularly polarized light can be set to because The zero-zero transmission frequency of the ground state and excited state Zeeman magneton energy levels is not affected by the external magnetic field and is a known constant;

[0040] S2. Simultaneously adjusting the frequencies of the left-handed circularly polarized light and the right-handed circularly polarized light to produce electromagnetically induced absorption. Specifically:

[0041] The frequency of left-handed circularly polarized light is reduced, and the frequency of right-handed circularly polarized light is increased at the same time. When the frequency of left-handed circularly polarized light is reduced to the transmission frequency equal to the g4 energy level of the ground state to the e2 energy level of the excited state, and the frequency of right-handed circularly polarized light is increased to the transmission frequency equal to the g2 energy level of the ground state to the e2 energy level of the excited state, both left-handed circularly polarized light and right-handed circularly polarized light will produce electromagnetic induced absorption phenomenon.

[0042] S3. Determine the magnetic sub-level interval frequency of the alkali metal atom based on the first transmitted light of the left-handed circularly polarized light and the right-handed circularly polarized light passing through the gas cell, specifically:

[0043] When left-handed and right-handed circularly polarized light produce electromagnetically induced absorption, the first transmitted light of the left-handed and right-handed circularly polarized light passing through the gas cell will have an absorption peak. This absorption peak can be observed by a photodetector. The frequency of the left-handed and right-handed circularly polarized light corresponding to this absorption peak can be used to determine the magnetic sub-energy level interval frequency of the alkali metal atom.

[0044] S4. Calculate the magnitude of the magnetic field at the location of the gas chamber based on the frequency of the magnetic sub-level intervals of the alkali metal atoms. Specifically:

[0045] According to the Zeeman effect, the frequency of the magnon energy level interval is determined by the magnitude of the external magnetic field, from which the magnitude of the magnetic field at the location of the gas chamber can be calculated.

[0046] S5. Setting the frequency of the right-handed circularly polarized light to a fixed frequency, the fixed frequency being equal to the transmission frequency between the g2 energy level of the ground state of the alkali metal atom and the e2 energy level of the excited state, wherein the transmission frequency is calculated based on the magnitude of the magnetic field, and adjusting the frequency of the left-handed circularly polarized light to cause the right-handed circularly polarized light to produce electromagnetically induced transparency and the left-handed circularly polarized light to produce electromagnetically induced absorption;

[0047] The transmission frequency calculated from the magnitude of the magnetic field is the transmission frequency between the g2 energy level of the ground state of the alkali metal atom and the e2 energy level of the excited state.

[0048] S6. Determine the direction of the magnetic field at the location of the air cell based on the second transmitted light of the left-handed circularly polarized light passing through the air cell. Specifically:

[0049] The electromagnetically induced transparency of right-handed circularly polarized light can be observed as the enhanced peak of the light transmitted through the atomic gas cell. The electromagnetically induced absorption of left-handed circularly polarized light can be observed as the absorbed peak of the light transmitted through the atomic gas cell. The enhanced peak corresponds to an enhanced transmitted light signal, while the absorbed peak corresponds to a weakened transmitted light signal. Therefore:

[0050] The angle between the absorption peak of the second transmitted light of the left-handed circularly polarized light passing through the gas cell and the polarization vector plane of the light and the direction of the static magnetic field can be determined. The angle can be determined by the peak value of the absorption peak. Thus the direction information of the external magnetic field.

[0051] Left-handed circularly polarized light and right-handed circularly polarized light are used to control the atomic quantum state and produce quantum interference effects in the atomic Zeeman magneton energy levels, namely the electromagnetically induced absorption phenomenon and the electromagnetically induced transparency phenomenon. The second transmitted light of the left-handed circularly polarized light will change with the angle between it and the direction of the magnetic field. In this way, the magnitude of the external magnetic field can be measured while providing information on the direction of the external magnetic field. Calculations show that the light transmission peak line width (full width at half maximum) of the electromagnetically induced absorption can reach 0.6 of the Zeeman magneton energy level interval frequency, which will also provide extremely high magnetic field measurement sensitivity.

[0052] Optionally, in the above technical solution, in S3, determining the magnetic sub-level interval frequency of the alkali metal atom according to the first transmitted light of the left-handed circularly polarized light and the right-handed circularly polarized light passing through the gas cell includes:

[0053] S30, detecting the first transmitted light using a photodetector to obtain an electrical signal corresponding to the first transmitted light, specifically:

[0054] The frequencies of left-handed circularly polarized light and right-handed circularly polarized light are initially set at the zero transmission frequency of the ground state and excited state magnon energy levels of the alkali metal atoms. At the same time, the frequency of the left-handed circularly polarized light is reduced and the frequency of the right-handed circularly polarized light is increased. Therefore, the first transmitted light passing through the atomic gas chamber is detected by a photodetector to obtain electrical signals corresponding to the first transmitted light of the left-handed and right-handed circularly polarized light.

[0055] S31, determining an absorption peak of the first transmitted light according to an electrical signal corresponding to the first transmitted light;

[0056] S32. Determine the magnetic sub-level interval frequency of the alkali metal atom according to the frequency of the left-handed circularly polarized light and the frequency of the right-handed circularly polarized light corresponding to the absorption peak of the first transmitted light.

[0057] Optionally, in the above technical solution, in S6, determining the direction of the magnetic field at the location of the air cell according to the second transmitted light of the left-handed circularly polarized light passing through the air cell includes:

[0058] S60: Detect the second transmitted light using a photodetector to obtain an electrical signal corresponding to the second transmitted light. Specifically:

[0059] Set the frequency of right-handed circularly polarized light from the ground state to the excited state of the atom Energy level transfer frequency. Because the frequency of the magnetic level interval is known, the ground state to the excited state The energy level transmission frequency can be calculated. Adjust the frequency of left-handed circularly polarized light. When the frequency of left-handed circularly polarized light is tuned to At the energy level transmission frequency, right-handed circularly polarized light undergoes electromagnetically induced transparency, and left-handed circularly polarized light undergoes electromagnetically induced absorption. Therefore, a photodetector is used to detect the second transmitted light of the left-handed circularly polarized light and obtain an electrical signal corresponding to the second transmitted light;

[0060] S61, determining an absorption peak of the second transmitted light according to an electrical signal corresponding to the second transmitted light;

[0061] S62. Determine the direction of the magnetic field at the location of the gas cell according to the peak value of the absorption peak of the second transmitted light. Specifically:

[0062] When the angle between the magnetic field and the polarization plane of the circularly polarized photoelectric vector decreases, the electromagnetically induced absorption of left-handed circularly polarized light is enhanced. Therefore, the left-handed circularly polarized light is absorbed more after passing through the gas cell. In this way, the amplitude of the second transmitted light absorption peak of the left-handed circularly polarized light measured by the photodetector is also larger. Therefore, the direction of the magnetic field at the location of the gas cell is determined based on the peak value of the absorption peak of the second transmitted light.

[0063] Optionally, in the above technical solution, the alkali metal atom is a rubidium atom or a cesium atom.

[0064] The measurement principle is as follows:

[0065] The alkali metal atom is a rubidium atom or a cesium atom, etc., and the rubidium atom is used as an example for explanation. Figure 2 As shown, left-handed circularly polarized light and right-handed circularly polarized light are coupled to rubidium atoms, generally rubidium 87 atoms, specifically 87 R5S 1 / 2 F=2→5P 1 / 2 F'=1 energy level transmission, the ground state of the rubidium atom is 87 R5S 1 / 2 F=2, excited state is 5P 1 / 2 F'=1.

[0066] Figure 2 In the figure, the middle cylinder represents the atomic gas cell, the xoz plane represents the plane of rotation of the electric field vector, the y-axis represents the direction of light propagation, represents the external magnetic field, represents the angle between the external magnetic field and the electric field vector plane, represents the linear polarization component after decomposition of the electric field vector, and represents the circular polarization component after decomposition of the electric field vector.

[0067] Figure 2 In the figure, a three-dimensional coordinate system is established with the center point of the air cell as the coordinate origin o. The y-axis of the three-dimensional coordinate system represents the propagation direction of left-handed circularly polarized light and right-handed circularly polarized light. The xoz plane is the position shown by the circle: it represents the rotation plane of the circularly polarized light electric field vector. represents the direction of the static magnetic field, It represents the angle between the plane of rotation of the electric field vector of light and the direction of the static magnetic field. represents the electric field vector, E represents the magnitude of the electric field vector, and E1 represents the magnitude of the circularly polarized light obtained after the decomposition of the original left-handed circularly polarized light. 1+ is the amplitude of the left-handed circularly polarized light obtained after decomposition, E 1- is the amplitude of right-handed circularly polarized light obtained after decomposition. It indicates that the linearly polarized light vector is obtained after the original circularly polarized light is decomposed. Represents the wave vector of the light field.

[0068] Left-handed circularly polarized light and right-handed circularly polarized light propagate in the same direction, and the electric field amplitudes of left-handed circularly polarized light and right-handed circularly polarized light are the same, both E, such as Figure 2 As shown, the circularly polarized light is decomposed into linear polarized light, left circularly polarized light and right circularly polarized light, thereby obtaining left circularly polarized light and right circularly polarized light, which are represented by the symbol σ + Represents left-handed circularly polarized light, using σ - represents right-handed circularly polarized light, ω1 represents the frequency of left-handed circularly polarized light, and ω2 represents the frequency of right-handed circularly polarized light. Left-handed circularly polarized light is abbreviated as LCPL and right-handed circularly polarized light is abbreviated as RCPL. LPL represents linearly polarized light, where:

[0069]

[0070] The above discussion on left-handed circularly polarized light σ + and right circularly polarized light σ - The formula shows that left-handed circularly polarized light and right-handed circularly polarized light can be decomposed again. + Can be decomposed into linearly polarized light E' L , left-handed circularly polarized light E 1+ and right circularly polarized light E 1- ; right circularly polarized light σ - Can be decomposed into linearly polarized light E″ L , left-handed circularly polarized light E 2+ and right circularly polarized light E 2- Combining the decomposed components gives the total linearly polarized light E L , total left-handed circularly polarized light E + and the total right-handed circularly polarized light E - The expression is as follows:

[0071]

[0072] For the convenience of research, the total left-handed circularly polarized light E +It is called GLPC, which converts the total right-handed circularly polarized light E - It is called GRPC. Rubidium atom 87 R5S 1 / 2 F=2→5P 1 / 2 F'=1 transmission interacts with circularly polarized light, such as Figure 3 As shown, Figure 3 In China, 5S 1 / 2 F=2 represents the ground state energy level. 1 / 2 F'=1 represents the excited state energy level. i is the ground state magnon energy level, i takes values from 1 to 5. e j is the excited state magnon energy level, j takes values from 1 to 3. Ω P ,Ω N and Ω L is the Rabi frequency of the coupling between the ground-state magnon energy level and the excited-state magnon energy level for left-handed circularly polarized light, right-handed circularly polarized light, and linearly polarized light. The arrowed lines indicate the corresponding transition channels, and δ is the ground-state magnon energy level separation.

[0073] The ground-state Zeeman sublevel spacing frequency of rubidium atoms is represented by δ, and the excited-state Zeeman sublevel spacing frequency is represented by δ / 3. Taking into account the Clebsch-Gordan effect (CG effect), the Rabi frequencies for each transition for left-handed circularly polarized light, right-handed circularly polarized light, and linearly polarized light are shown in Table 1 below.

[0074] Table 1:

[0075]

[0076] like Figure 3 As shown, where Ω p Indicates left-handed circularly polarized light E + The Rabi frequency that causes the energy level transition, subscript 1-6 represents Figure 3 The corresponding energy level transition, for example, 5 represents left-handed circularly polarized light E 1+ The Rabi frequency that causes the transition from the ground state energy level g5 to the excited state energy level e1, 6 represents left-handed circularly polarized light E 2+ The Rabi frequency that causes the transition from the ground state energy level g5 to the excited state energy level e1. Ω N Indicates right-handed polarized light E - The Rabi frequency that causes the energy level transition, subscript 1-6 represents Figure 3 The Rabi frequency corresponding to the energy level transition. L Indicates linearly polarized light E L The Rabi frequency that causes the energy level transition, subscript 1-6 represents Figure 3 The corresponding energy level transition, for example, 1 represents linearly polarized light Rabi frequency that causes the transition from the ground state energy level g2 to the excited state energy level e3, 2 represents linearly polarized light The Rabi frequency that causes the transition from the ground state energy level g2 to the excited state energy level e3. Assume represents the transmission frequency from the ground state energy level g3 to the excited state energy level e2, which is set as: The frequency of LCPL can be written as ω1=ω-Δ1, and the frequency of RCPL can be written as ω2=ω+Δ2, where Δ1 is the detuning amount, which represents the left-handed circularly polarized light σ + The frequency ω1 is related to the transmission frequency The difference. Similarly, Δ2 is also the detuning amount, which means right-handed circularly polarized light σ - The frequency ω2 is related to the transmission frequency g1, g2, g3, g4, g5 represent the energy levels of the ground state Zeeman magnetons; e1, e2, e3 represent the energy levels of the excited state Zeeman magnetons. The interaction Hamiltonian H of the system under the spin wave approximation is int It can be written as:

[0077]

[0078] The main equation of the system in the interaction picture is: Where ρ is the density matrix element and Γ is the total spontaneous emission rate of an excited state Zeeman magneton energy level. e is the excited state projection operator, expressed as P e =|e1><e1|+|e2><e2|+|e3><e3|. The system has 8 sub-energy levels, so there are 64 equations in total, among which the 6 equations related to light absorption are as follows:

[0079] 1)

[0080] 2)

[0081] 3)

[0082] 4)

[0083] 5)

[0084] 6)

[0085] in represents the ground state magnon energy level g i and the excited state magnon energy level e j The density matrix element of , i takes values from 1 to 5 to represent different ground state magnon energy levels, and j takes values from 1 to 3 to represent different excited state magnon energy levels. represents the ground state magnon energy level g m and g nThe density matrix elements of , m and n take values from 1 to 5 to represent different ground state magnon energy levels. represents the excited state magnon energy level e k and e l The density matrix elements of k and l take values of 1 to 3 to represent different excited state magnon energy levels. The above set of equations, i.e., the six equations related to light absorption, can be solved using the Runge-Kutta numerical method. Since the equations contain time-dependent exponential terms, the numerical solutions will also oscillate with time. We can find the average value of the numerical solutions over a period of time to reveal the physical properties of the system. The results shown in this application are all time-averaged results. Electric susceptibility of rubidium 87 atomic gas dielectric in atomic gas chamber It is expressed by the following formula:

[0086]

[0087] Where N represents the density of rubidium 87 atoms in the atomic gas chamber, Indicates that the electron moves from the ground state energy level g i To the excited state energy level e j The dipole momentum of the transition. ε0 is the dielectric constant of vacuum. represents the ground state magnon energy level g i and the excited state magnon energy level e j The density matrix element of the electric susceptibility is α. The real and imaginary parts of the electric susceptibility correspond to the dispersion and absorption properties of the rubidium 87 atomic gas medium in the atomic gas chamber. + ) and the total right-handed circularly polarized light GRPC (α - ) corresponds to the following density matrix elements:

[0088]

[0089]

[0090] In the above formula, imag represents the imaginary part of the result of the expression. The above formula shows that the coefficient of absorption of left and right circularly polarized light when passing through the atomic gas cell is proportional to this imaginary part. First, assume that the detuning amounts Δ1 and Δ2 change simultaneously, and the spontaneous emission rate Γ of an excited state Zeeman level is set to 1. Other physical quantities are in Γ units. The frequency difference of the ground state Zeeman sublevel is δ = 1. Initially, the frequencies of left-handed circularly polarized light and right-handed circularly polarized light can be set to The ground state and excited state energy level transmission frequency is not affected by the external magnetic field and is a constant value. The detuning amount Δ1 and Δ2 changes from 0.98 to 1.02. When Δ1=Δ2=1, the frequency of RCPL is equal to Transmission frequency, the frequency of LCPL is equal to Transmission frequency. Figure 4In the example, it is assumed that the RabiRabi frequency from the ground state to the excited state is is 2. Assume that the ground state magnon energy level splitting δ is 6.8×10 5 Hz, Figure 4 The results in the figure are obtained after 0.13s time averaging.

[0091] Figure 4 The curve showing the change of the absorption coefficient of the total left-handed circularly polarized light (GLPC) and the total right-handed circularly polarized light (GRPC) when passing through the atomic gas cell with the detuning amount of light (light frequency). The Rabi frequency is (a) (b) (c) (d) Jiao Ru Figure 2 As shown. Figure 4 (a) It can be seen that when the angle When the detuning values Δ1 and Δ2 change from 0.98 to 1.02, the absorption of GLPC and GRPC is zero. The reason is that the energy level transition corresponding to linearly polarized light (LPL) does not exist, so the coherence of the system remains stable when the detuning values Δ1 and Δ2 change. Figure 4 (b) Figure 4 (c) Figure 4 (d) It can be seen that due to the existence of LPL transitions, the coherence of the system changes dramatically with the change of detuning Δ1 and Δ2. The absorption curve of light is dispersive. The line width of the absorption curve is about 0.6 of the Zeeman sublevel spacing frequency. If the Zeeman sublevel spacing frequency is 6.8×10 5 Hz, the line width of the light absorption curve is 40Hz. Rabi frequency The case of 0.2 is shown in Figure 5 middle.

[0092] Figure 4 In the curve, the absorption coefficient of left-handed (LCPL) and right-handed circularly polarized light (RCPL) passing through the atomic gas cell changes with the detuning amount of light, that is, the frequency of light. When Δ1=Δ2=1, the frequency of RCPL is equal to Transmission frequency, the frequency of LCPL is equal to Transmission frequency. The Rabi frequency of light is is 2. At this time, the absorption curve of visible light is dispersive and has an extremely narrow line width. (a) (b) (c) (d) The angle is the angle between the plane of the light's electric vector and the direction of the magnetic field, such as Figure 2 shown.

[0093] Figure 5 The curve showing the change of the absorption coefficient of GLPC and GRPC as they pass through the atomic gas cell with the detuning amount of light (light frequency) is shown. (a) (b) (c) from Figure 5 It can be seen that the absorption curves of GLPC and GRPC show the type of electromagnetic induced absorption (EIA). The absorption peak of light is more prominent under weak light conditions. And as the angle The decrease in EIA increases the amplitude. LPL, GLPC and GRPC form an N-type transmission channel, so the ground state coherence is adjusted. The quantum constructive interference between LPL and the circularly polarized light transition channel is the reason for the formation of EIA. If LCPL and RCPL are The transmission frequency begins to change, and when the frequency change is equal to the frequency difference of the Zeeman magneton energy level, an absorption peak appears, and the line width of the absorption peak is about 0.5 of the 100,000th of the Zeeman magneton energy level frequency interval. Figure 3 and Figure 5 The results provide an effective means to measure the external magnetic field. The extremely narrow light absorption linewidth provides high magnetic field measurement sensitivity, while the amplitude of the absorption curve provides directional information of the external magnetic field.

[0094] Figure 5 middle, Figure 5 The absorption coefficient of left-handed (LCPL) and right-handed circularly polarized light (RCPL) passing through the atomic gas cell varies with the detuning amount (frequency) of the light. The Rabi frequency of the light is (a) (b) (c) The absorption curves of GLPC and GRPC exhibit electromagnetically induced absorption (EIA), with the absorption peak being more pronounced under weak light conditions. EIA has an extremely narrow linewidth, making it extremely sensitive to changes in the energy level spacing of the Zeeman magneton. This allows for precise measurements of weak magnetic fields.

[0095] The detuning amount Δ2 is fixed at 1, and the detuning amount Δ1 varies around 1.

[0096] Since the magnon energy level spacing can be measured, Δ2 can be set to 1 (equal to the magnon energy level spacing frequency), and the detuning amount Δ1 is changed from 0.8 to 1. Figure 6 middle The angle is

[0097] Figure 6 The curve showing the change of the absorption coefficient of GLPC and GRPC as they pass through the atomic gas cell with the detuning amount of light (light frequency) is shown. (a)G=0.1; (b)G=0.2; (c)G=0.3. Figure 6 It shows that there is electromagnetically induced transparency for GRPC. As the optical power of RCPL increases, the line width of electromagnetically induced transparency also increases. The frequency of RCPL is set at Transmission frequency. When the LCPL frequency is tuned to When transmitting frequency, the coherent transmission channel and is established, so the electromagnetically induced transparency phenomenon occurs. Figure 7 middle The angle is

[0098] Figure 6 In the figure, the absorption coefficient of left-handed (LCPL) and right-handed circularly polarized light (RCPL) changes with the detuning amount of light (light frequency) when passing through the atomic gas cell, where the detuning amount of right-handed circularly polarized light Δ2=1, and the detuning amount of left-handed circularly polarized light Δ1 changes. The Rabi frequencies of light are (a) G = 0.1; (b) G = 0.2; and (c) G = 0.3. It can be seen that for right-handed circularly polarized light, the absorption curve exhibits an electromagnetically induced transparency type, and the linewidth widens with increasing optical power.

[0099] Figure 7 The curve showing the change of the absorption coefficient of GLPC and GRPC as they pass through the atomic gas cell with the detuning amount of light (light frequency) is shown. (a) G = 0.1; (b) G = 0.2; (c) G = 0.3. Figure 7 We can see that the electromagnetically induced absorption phenomenon is present for GLPC and the electromagnetically induced transparency phenomenon is present for GRPC, and the two phenomena exist simultaneously. The line width of the electromagnetically induced transparency is significantly wider than that of the electromagnetically induced absorption. The absorption curves of GLPC and GRPC are Figure 8 Further explained in.

[0100] Figure 7 This is a curve showing the absorption coefficient of left-handed (LCPL) and right-handed circularly polarized light (RCPL) changing with the detuning amount (light frequency) of light when passing through the atomic gas cell, where the detuning amount of right-handed circularly polarized light is Δ2=1, and the detuning amount of left-handed circularly polarized light is Δ1. The Rabi frequencies of light are (a) G = 0.1; (b) G = 0.2; and (c) G = 0.3. Electromagnetic induced absorption (EIA) occurs for left-handed circularly polarized light, while EIA occurs for right-handed circularly polarized light. Both phenomena coexist. The linewidth of EIA is much narrower than that of EIA, which is highly advantageous for precise magnetic field measurements.

[0101] Figure 8The curve showing the change of the absorption coefficient of GLPC and GRPC as they pass through the atomic gas cell with the detuning amount of light (light frequency) is shown. (a) G = 0.1; (b) G = 0.3. Figure 8 The line width of the electromagnetically induced absorption of GLPC is about 0.05 of the Zeeman frequency of the interval between adjacent magnon energy levels. Figure 3 The electron transition channel between energy levels has been explained. An N-type transmission channel is formed. When part of the GLPC light and When the transition channel resonates, the quantum constructive interference between the GLPC and LPL components causes the electromagnetically induced absorption effect. To confirm this physical analysis, we consider the angle Compared with the angle In this case, the LPL light component will be enhanced, from which it can be deduced that the electromagnetic induced absorption phenomenon will be enhanced. Figure 9 The calculation results confirm this analysis.

[0102] Figure 8 The middle curve shows the absorption coefficient of left-handed (LCPL) and right-handed circularly polarized light (RCPL) when passing through the atomic gas cell as the light detuning amount (light frequency) changes, where the detuning amount of right-handed circularly polarized light Δ2 = 1, and the detuning amount of left-handed circularly polarized light Δ1 changes. The Rabi frequencies of light are (a) G = 0.1 and (b) G = 0.3. It can be seen that the electromagnetically induced absorption curve of left-handed circularly polarized light has an extremely narrow linewidth.

[0103] Figure 9 The curve showing the change of the absorption coefficient of GLPC and GRPC as they pass through the atomic gas cell with the detuning amount of light (light frequency) is shown. (a), (b) G = 0.1; (c), (d) G = 0.3. Figure 9 The middle curve shows the absorption coefficient of left-handed (LCPL) and right-handed circularly polarized light (RCPL) when passing through the atomic gas cell as the light detuning amount (light frequency) changes, where the detuning amount of right-handed circularly polarized light Δ2 = 1, and the detuning amount of left-handed circularly polarized light Δ1 changes. The Rabi frequency of light is (a), (b) G = 0.1; (c), (d) G = 0.3. Figure 9 and Figure 8 By comparison, it can be seen that as the angle between the electric vector plane and the magnetic field direction increases becomes smaller, and the electromagnetically induced absorption signal of left-handed circularly polarized light is enhanced, which means that the amplitude of the electromagnetically induced absorption signal of light can be used to indicate the direction of the external magnetic field.

[0104] Figure 9 For Figure 9 (a) and (b), the Rabi frequency is G = 0.1. Figure 9(c) and (d) Rabi frequency is G = 0.3. and Figure 8 In comparison, we can see Figure 9 The electromagnetically induced absorption signal is significantly enhanced, which can be understood from the perspective that the GLPC and LPL light components are enhanced. Figure 9 The extremely narrow linewidth electromagnetically induced absorption signal will provide high sensitivity to changes in the external magnetic field and can be used for precise measurement of weak external magnetic fields.

[0105] By studying the interaction between two beams of left-handed circularly polarized light and right-handed circularly polarized light and rubidium-87 atoms, a scheme for measuring weak magnetic fields using electromagnetically induced absorption and electromagnetically induced transparent quantum interference effects is proposed. There are two methods. The first method is to change the frequency of left-handed and right-handed circularly polarized light at the same time to observe the electromagnetically induced absorption phenomenon. The absorption peak line width of the light is extremely narrow, reaching 0.06 of the frequency interval of the magnon energy level, which will provide extremely high external magnetic field measurement sensitivity. The second method is to couple the right-handed circularly polarized light to 87 Rb 5S 1 / 2 F=2→5P 1 / 2 F'=1 transition When the angle between the magnetic field and the polarization plane of light is 90 degrees, electromagnetically induced transparency (EMIT) is observed for right-handed circularly polarized light. When the angle between the magnetic field and the polarization plane of light is not 90 degrees, EMIT and EMIA are simultaneously observed for both left-handed and right-handed circularly polarized light. The linewidth of EMIA is only 0.05% of the magnon energy level spacing, and the signal amplitude of EMIA varies with the angle between the magnetic field and the polarization plane of light. This provides a highly sensitive method for precisely measuring the magnitude and direction of external magnetic fields.

[0106] A magnetic field measurement solution of the present application is described through another embodiment, including:

[0107] S100, coupling rubidium-87 atoms using two beams of left-handed circularly polarized light and right-handed circularly polarized light 87 R5S 1 / 2 F=2→5P 1 / 2 F'=1 energy level transition. Assume that the transition frequency from the ground state Zeeman magnon energy level to the excited state magnon energy level is Assume that the frequency interval of the magnon energy level is set to δ = 1. At this time, the frequencies of left-handed circularly polarized light and right-handed circularly polarized light can be written as ω1 = ω-Δ1 and ω2 = ω + Δ2. Δ1 and Δ2 are the detuning amounts. Initially, the frequencies of left-handed circularly polarized light and right-handed circularly polarized light can be set to The transmission frequency of the ground state and excited state energy levels is not affected by the external magnetic field and is a certain value;

[0108] S101, adjust the frequency of left-handed circularly polarized light and right-handed circularly polarized light at the same time, the method is to increase the frequency of left-handed circularly polarized light and reduce the frequency of right-handed circularly polarized light, when Δ1=Δ2=1, that is, Δ1 and Δ2 are equal to the magnon energy level interval frequency, the right-handed circularly polarized light is equal to Transmission frequency, left-handed circularly polarized light is equal to Transmission frequency. At this time, the electromagnetically induced absorption phenomenon of left-handed circularly polarized light and right-handed circularly polarized light can be observed. Using a photodetector to observe the transmitted light, the absorption peak of light can be observed. If the magnetic energy level interval δ is 6.8×10 5 Hz, and the line width of the light absorption peak is 40Hz. When observing the light absorption peak, it is necessary to average the signal within a certain period of time to eliminate the oscillation of the signal. δ is 6.8×10 5 The average time of the signal at Hz is 0.13 seconds. Because the laser frequency after frequency adjustment is known and the initial laser frequency is known, the magnon energy level interval frequency can be calculated from the laser frequency when the electromagnetic induced absorption peak appears, that is, the external magnetic field size can be deduced. The extremely narrow line width of the light absorption peak will provide high sensitivity for detecting external magnetic fields, such as Figure 11 As shown in the figure, the schematic diagram of the coupling between light and the energy level of rubidium 87 atoms. The incident left-handed and right-handed circularly polarized light can be decomposed into three components, namely left-handed, linearly polarized and right-handed circularly polarized light. The coupling of various polarized light components with the ground state magnon energy level and excited state magnon energy level of rubidium 87 atoms is shown in the figure above. i Represents the ground state magnon energy level, i from 1 to 5 means there are 5 different magnon energy levels. i Represents the excited state magnon energy level, i from 1 to 3 means there are 3 different magnon energy levels. 1 / 2 F=2 means ground state, 5P 1 / 2 F'=1 indicates an excited state.

[0109] S102, the magnon energy level interval frequency can be determined by S101, so that the frequency of right-handed circularly polarized light can be set at The transmission frequency is due to The transmission frequency can be calculated. At this time, adjust the frequency of the left-handed circularly polarized light. When the frequency of the left-handed circularly polarized light is tuned to When transmitting at a specific frequency, different quantum interference effects occur depending on the angle between the magnetic field and the polarization plane of the light's electric vector. When the angle between the magnetic field and the light's polarization plane is 90 degrees, electromagnetically induced transparency occurs for right-handed circularly polarized light. As the angle decreases, electromagnetically induced absorption occurs for left-handed circularly polarized light. Furthermore, as this angle decreases, the electromagnetically induced absorption signal becomes stronger, and the peak amplitude of the light absorption measured by the photodetector also increases, providing information about the direction of the external magnetic field. The signal measured in step 3 also needs to be averaged, with the same averaging time as in step S101.

[0110] The absorption measurement of light can be done by splitting the transmitted light into two optical paths, and then using two light detectors to detect the absorption of left-handed and right-handed circularly polarized light respectively. The inspection of circularly polarized light can be achieved by combining a linear polarizer and a quarter-wave plate, such as Figure 10 shown. Figure 10 In the coordinate system, the cylinder in the middle is the rubidium atom gas cell, the xoz coordinate plane is the plane of rotation of the electric field vector of light, and the y-axis represents the direction of light propagation. represents the electric field vector, represents the magnetic field vector. The angle between the electric field vector plane and the magnetic field direction. Quarter-wave plates and polarizers are used for light splitting, separating left-handed and right-handed circularly polarized light from a mixture of the two. For example, the photodetector above detects left-handed circularly polarized light, while the photodetector below detects right-handed circularly polarized light.

[0111] Electromagnetically induced transparency (EMIT) and electromagnetically induced absorption (EMIA) are quantum interference effects that can be applied to quantum precision measurements, such as the precise measurement of magnetic fields in atomic magnetometers. Typically, in optical experiments like EMI, two laser beams of different frequencies are used to create quantum coherence in atoms, distributing them at different energy levels to achieve ground-state or excited-state coherence. When applied to magnetic field measurements, one laser frequency is typically fixed while the other is swept. When the laser frequency resonates with the Zeeman magnon energy levels, quantum coherence can be achieved between the atomic magnon energy levels. The resulting quantum destructive interference effect weakens or even eliminates the absorption of light by the atomic medium. A transmission peak is observed by the light detector, indicating the spacing between the magnon energy levels and, therefore, the magnitude of the external magnetic field can be inferred. Magnetic field measurements based on EMI typically only reflect the magnitude of the magnetic field. Measuring the direction of the magnetic field requires multiple probes or more complex techniques.

[0112] In quantum optics and quantum information technology experiments, quantum interference effect is an important resource and has important application value in the fields of physical precision measurement. 87 R5S 1 / 2 F=2→5P 1 / 2 At the F'=1 energy level, electromagnetically induced absorption and electromagnetically induced transparency effects can be observed simultaneously for the two beams of left-handed and right-handed circularly polarized light at some light transmission angles.

[0113] Existing technologies for preparing atomic quantum interference effects, such as the electromagnetic induction effect, use multiple laser beams of different frequencies to couple different energy levels of atoms. When the light resonates with the atomic energy level, a coherent state is prepared in the atomic energy level, causing the electron transition to undergo quantum interference destructive effect, and obtaining the transmission peak of the outgoing light to indicate the size of the external magnetic field. Usually, this can only obtain information about the size of the magnetic field, and cannot directly indicate the direction of the magnetic field. The optically pumped magnetic resonance technology uses optical pumping to obtain the polarized state of the atomic energy state, and then uses a radio frequency field to transfer the atomic population. When the radio frequency field resonates with the atomic magnetic energy level, the maximum atomic population transfer effect is obtained, and the absorption of the pump light is also the strongest, thereby indicating the size of the external magnetic field. The quantum interference effect is not used, and the sensitivity of the external magnetic field measurement is limited by the line width of the light transmission peak, and the direction information of the external magnetic field cannot be directly obtained.

[0114] The present invention utilizes two beams of left-handed and right-handed circularly polarized laser light to realize the control of atomic quantum states and generate quantum interference effects in the atomic Zeeman magneton energy levels. Under certain light transmission angles, electromagnetically induced absorption and electromagnetically induced transparency effects can be simultaneously observed for these two beams of light, and the light transmission peak changes with the angle between the light and the magnetic field direction. In this way, the magnitude of the external magnetic field can be measured while providing information on the direction of the external magnetic field. Calculations show that the light transmission peak line width (full width at half maximum) of the electromagnetically induced absorption can reach 0.6 of the Zeeman magneton energy level interval frequency, which will also provide extremely high magnetic field measurement sensitivity.

[0115] In the above embodiments, although the steps are numbered S1, S2, etc., these are only specific embodiments given in this application. Those skilled in the art can adjust the execution order of S1, S2, etc. according to actual conditions, which is also within the scope of protection of the present invention. It can be understood that in some embodiments, some or all of the above embodiments may be included.

[0116] like Figure 12 As shown, a magnetic field measurement system 200 according to an embodiment of the present invention includes a presetting module 210, a first adjustment module 220, a first determination module 230, a calculation module 240, a second adjustment module 250 and a second determination module 260;

[0117] The presetting module 210 is used to preset the frequency of the left-handed circularly polarized light and the frequency of the right-handed circularly polarized light so that the left-handed circularly polarized light and the right-handed circularly polarized light are coupled to the ground state and excited state Zeeman magneton energy levels of the alkali metal atoms placed in the gas cell;

[0118] The first adjustment module 220 is used to adjust the frequency of the left-handed circularly polarized light and the frequency of the right-handed circularly polarized light to generate electromagnetic induced absorption.

[0119] The first determining module 230 is configured to determine the magnetic sub-level interval frequency of the alkali metal atom according to the first transmitted light of the left-handed circularly polarized light and the right-handed circularly polarized light passing through the gas cell;

[0120] The calculation module 240 is used to calculate the magnitude of the magnetic field at the location of the gas chamber according to the interval frequency of the magnetic sub-energy levels of the alkali metal atoms;

[0121] The second adjustment module 250 is used to set the frequency of the right-handed circularly polarized light to a fixed frequency, the fixed frequency being equal to the transmission frequency between the g2 energy level of the ground state of the alkali metal atom and the e2 energy level of the excited state, wherein the transmission frequency is calculated according to the magnitude of the magnetic field, and the frequency of the left-handed circularly polarized light is adjusted to cause the right-handed circularly polarized light to produce electromagnetically induced transparency and the left-handed circularly polarized light to produce electromagnetically induced absorption;

[0122] The second determining module 260 is configured to determine the direction of the magnetic field at the location of the air cell according to the second transmitted light of the left-handed circularly polarized light passing through the air cell.

[0123] Left-handed circularly polarized light and right-handed circularly polarized light are used to control the atomic quantum state and produce quantum interference effects in the atomic Zeeman magneton energy levels, namely the electromagnetically induced absorption phenomenon and the electromagnetically induced transparency phenomenon. The second transmitted light of the left-handed circularly polarized light will change with the angle between it and the direction of the magnetic field. In this way, the magnitude of the external magnetic field can be measured while providing information on the direction of the external magnetic field. Calculations show that the light transmission peak line width (full width at half maximum) of the electromagnetically induced absorption can reach 0.6 of the Zeeman magneton energy level interval frequency, which will also provide extremely high magnetic field measurement sensitivity.

[0124] Optionally, in the above technical solution, the first determining module 230 is specifically configured to:

[0125] detecting the first transmitted light using a photodetector to obtain an electrical signal corresponding to the first transmitted light;

[0126] determining an absorption peak of the first transmitted light according to an electrical signal corresponding to the first transmitted light;

[0127] The magnetic sub-level interval frequency of the alkali metal atom is determined according to the frequency of the left-handed circularly polarized light and the frequency of the right-handed circularly polarized light corresponding to the absorption peak of the first transmitted light.

[0128] Optionally, in the above technical solution, the second determining module 260 is specifically configured to:

[0129] detecting the second transmitted light using a photodetector to obtain an electrical signal corresponding to the second transmitted light;

[0130] determining an absorption peak of the second transmitted light according to an electrical signal corresponding to the second transmitted light;

[0131] The direction of the magnetic field at the location of the gas cell is determined according to the peak value of the absorption peak of the second transmitted light.

[0132] Optionally, in the above technical solution, the alkali metal atom is a rubidium atom or a cesium atom.

[0133] The parameters and steps of each unit module in the magnetic field measurement system 200 of the present invention to achieve corresponding functions can be referred to the parameters and steps in the embodiment of the magnetic field measurement method above, and will not be repeated here.

[0134] A storage medium according to an embodiment of the present invention stores instructions, and when a computer reads the instructions, the computer executes any one of the above-mentioned magnetic field measurement methods.

[0135] An electronic device according to an embodiment of the present invention includes a processor and the above-mentioned storage medium, wherein the processor executes instructions in the storage medium. The electronic device can be a computer, a mobile phone, etc.

[0136] Those skilled in the art will appreciate that the present invention may be implemented as a system, method or computer program product.

[0137] Therefore, the present disclosure may be embodied in the following forms: entirely in hardware, entirely in software (including firmware, resident software, microcode, etc.), or in a combination of hardware and software, generally referred to herein as a "circuit," "module," or "system." Furthermore, in some embodiments, the present disclosure may be embodied in the form of a computer program product embodied in one or more computer-readable media, wherein the computer-readable media contains computer-readable program code.

[0138] Any combination of one or more computer-readable media can be used. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or component, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, device, or device.

[0139] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A magnetic field measurement method, characterized in that: include: Presetting the frequency of the left-handed circularly polarized light and the frequency of the right-handed circularly polarized light so that the left-handed circularly polarized light and the right-handed circularly polarized light are coupled to the ground state and excited state Zeeman magneton energy levels of the alkali metal atoms placed in the gas cell; Simultaneously adjusting the frequency of the left-handed circularly polarized light and the frequency of the right-handed circularly polarized light to produce electromagnetically induced absorption; determining a magnetic sub-level spacing frequency of the alkali metal atom according to first transmitted light of the left-handed circularly polarized light and the right-handed circularly polarized light passing through the gas cell; Calculating the magnitude of the magnetic field at the location of the gas chamber according to the magnetic sub-energy level interval frequency of the alkali metal atoms; The frequency of the right-handed circularly polarized light is set at a fixed frequency, the magnitude of which is consistent with the ground state of the alkali metal atom. g2 Energy level to excited state e2 The transmission frequencies between the energy levels are equal, wherein the transmission frequency is calculated based on the magnitude of the magnetic field, and the frequency of the left-handed circularly polarized light is adjusted to cause the right-handed circularly polarized light to produce electromagnetically induced transparency and the left-handed circularly polarized light to produce electromagnetically induced absorption; The direction of the magnetic field at the location of the air cell is determined according to the second transmitted light of the left-handed circularly polarized light passing through the air cell.

2. A magnetic field measurement method according to claim 1, characterized in that: Determining the magnetic sub-level spacing frequency of the alkali metal atom according to the first transmitted light of the left-handed circularly polarized light and the right-handed circularly polarized light passing through the gas cell comprises: detecting the first transmitted light using a photodetector to obtain an electrical signal corresponding to the first transmitted light; determining an absorption peak of the first transmitted light according to an electrical signal corresponding to the first transmitted light; The magnetic sub-level interval frequency of the alkali metal atom is determined according to the frequency of the left-handed circularly polarized light and the frequency of the right-handed circularly polarized light corresponding to the absorption peak of the first transmitted light.

3. A magnetic field measurement method according to claim 2, characterized in that: Determining the direction of the magnetic field at the location of the air cell according to the second transmitted light of the left-handed circularly polarized light passing through the air cell comprises: detecting the second transmitted light using a photodetector to obtain an electrical signal corresponding to the second transmitted light; determining an absorption peak of the second transmitted light according to the electrical signal corresponding to the second transmitted light; The direction of the magnetic field at the location of the gas cell is determined according to the peak value of the absorption peak of the second transmitted light.

4. A magnetic field measurement method according to any one of claims 1 to 3, characterized in that: The alkali metal atom is a rubidium atom or a cesium atom.

5. A magnetic field measurement system, characterized in that: It includes a presetting module, a first adjusting module, a first determining module, a calculating module, a second adjusting module and a second determining module; The presetting module is used to preset the frequency of left-handed circularly polarized light and the frequency of right-handed circularly polarized light so that the left-handed circularly polarized light and the right-handed circularly polarized light are coupled to the ground state and excited state Zeeman magneton energy levels of the alkali metal atoms placed in the gas cell; The first adjustment module is used to: simultaneously adjust the frequency of the left-handed circularly polarized light and the frequency of the right-handed circularly polarized light to generate electromagnetic induced absorption; The first determining module is configured to determine the magnetic sub-level interval frequency of the alkali metal atom according to the first transmitted light of the left-handed circularly polarized light and the right-handed circularly polarized light passing through the gas cell; The calculation module is used to calculate the magnitude of the magnetic field at the location of the gas chamber according to the magnetic sub-level interval frequency of the alkali metal atoms; The second adjustment module is used to set the frequency of the right-handed circularly polarized light to a fixed frequency, the magnitude of the fixed frequency being related to the ground state of the alkali metal atom. g2 Energy level to excited state e2 The transmission frequencies between the energy levels are equal, wherein the transmission frequency is calculated based on the magnitude of the magnetic field, and the frequency of the left-handed circularly polarized light is adjusted to cause the right-handed circularly polarized light to produce electromagnetically induced transparency and the left-handed circularly polarized light to produce electromagnetically induced absorption; The second determining module is configured to determine the direction of the magnetic field at the location of the air cell according to the second transmitted light of the left-handed circularly polarized light passing through the air cell.

6. A magnetic field measurement system according to claim 5, characterized in that: The first determining module is specifically configured to: detecting the first transmitted light using a photodetector to obtain an electrical signal corresponding to the first transmitted light; determining an absorption peak of the first transmitted light according to an electrical signal corresponding to the first transmitted light; The magnetic sub-level interval frequency of the alkali metal atom is determined according to the frequency of the left-handed circularly polarized light and the frequency of the right-handed circularly polarized light corresponding to the absorption peak of the first transmitted light.

7. A magnetic field measurement system according to claim 6, characterized in that: The second determining module is specifically configured to: detecting the second transmitted light using a photodetector to obtain an electrical signal corresponding to the second transmitted light; determining an absorption peak of the second transmitted light according to the electrical signal corresponding to the second transmitted light; The direction of the magnetic field at the location of the gas cell is determined according to the peak value of the absorption peak of the second transmitted light.

8. A magnetic field measurement system according to any one of claims 5 to 7, characterized in that: The alkali metal atom is a rubidium atom or a cesium atom.

9. A storage medium, characterized in that: The storage medium stores instructions, and when a computer reads the instructions, the computer is enabled to execute a magnetic field measurement method according to any one of claims 1 to 4.

10. An electronic device, characterized in that: The device comprises a processor and the storage medium according to claim 9, wherein the processor executes instructions in the storage medium.

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