CN112556678A - Method for measuring nuclear polarizability of atomic spin gyroscope based on adiabatic fast channel - Google Patents

Method for measuring nuclear polarizability of atomic spin gyroscope based on adiabatic fast channel Download PDF

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CN112556678A
CN112556678A CN202011332981.1A CN202011332981A CN112556678A CN 112556678 A CN112556678 A CN 112556678A CN 202011332981 A CN202011332981 A CN 202011332981A CN 112556678 A CN112556678 A CN 112556678A
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杜鹏程
全伟
段利红
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Beihang University
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Abstract

A method for measuring the nuclear polarizability of an atomic spin gyroscope based on an adiabatic fast channel comprises the steps of turning the macroscopic polarization direction of the nuclear spin by adopting the adiabatic fast channel, measuring the resonance frequency difference value of outer-layer electrons before and after turning by adopting an electron paramagnetic resonance mode to determine the nuclear spin polarizability, and accurately measuring the nuclear polarizability of the atomic gyroscope in real time in situ without damage during online work, so that the miniaturization of the gyroscope and the accurate control of the nuclear polarizability in a closed loop are facilitated.

Description

Method for measuring nuclear polarizability of atomic spin gyroscope based on adiabatic fast channel
Technical Field
The invention relates to a technology for measuring the nuclear polarizability by an atomic gyroscope, in particular to a method for measuring the nuclear polarizability by an atomic spin gyroscope based on an adiabatic fast channel.
Background
The atomic Spin gyroscope based on Spin-Exchange Relaxation-Free (SERF) technology has the characteristics of high theoretical precision, small volume, low cost, small dynamic range and the like, and is suitable for a future platform type inertial navigation system. The main core element for realizing the fixed axis property of the atomic spin gyro is the macroscopic polarization of atomic nuclei. The SERF type atomic gyroscope realizes alkali metal electron spin polarization through circularly polarized light, then realizes nuclear hyperpolarization through atomic spin exchange collision, and when an external compensation magnetic field and a magnetic field formed by nuclear polarization and the like are in large reversal, alkali metal outer layer electrons are not interfered by the external magnetic field and are only influenced by external rotation, so that inertial measurement is realized. The nuclear polarization intensity is a key point influencing the performance of the atomic spin gyro, and how to effectively and accurately measure the nuclear polarization intensity is a key point for realizing the quantitative optimization of the high-performance gyro and a basis for realizing the closed-loop control of the nuclear polarization in the atomic gyro.
In general, measurement is performed by using Free Induced Decay (FID), which requires applying a step magnetic field in a direction transverse to the polarization of the atomic nucleus, detecting a precession signal of the magnetic moment of the atomic nucleus under the magnetic field, and obtaining the relative strength of the polarization of the atomic nucleus through the precession signal of the magnetic moment of the atomic nucleus. However, such a detection method has the following disadvantages: 1. the influence of the background noise of the transverse magnetic field on the detection result cannot be shielded; 2. only the proportional change of the nuclear spin polarization intensity can be obtained, and the nuclear spin polarization intensity cannot be accurately measured; 3. the detection light is introduced to carry out indirect measurement, and various noises in the detection process are inevitably coupled; 4. the FID measurement is non-nondestructive every time, and online nondestructive real-time measurement cannot be realized. The problems can cause that the nuclear spin polarization can not be accurately measured, and meanwhile, the closed-loop control of the nuclear spin polarization strength can not be realized, so that the axis type of the gyroscope can not be controlled in a closed-loop manner, and the zero-offset stability of the gyroscope is influenced.
Disclosure of Invention
Aiming at the defects or shortcomings of the prior art, the invention provides a method for measuring the nuclear polarizability of an atomic spin gyroscope based on an adiabatic fast channel.
The technical solution of the invention is as follows:
the method for measuring the nuclear polarizability of the atomic spin gyroscope based on the adiabatic fast channel is characterized in that the nuclear spin macroscopic polarization direction of the atomic spin gyroscope is in the same direction as pump light when the atomic spin gyroscope works, the nuclear spin macroscopic polarization direction is overturned by the adiabatic fast channel, so that the magnetic field change sensed by outer electrons of alkali metal atoms in an alkali metal gas chamber of the atomic spin gyroscope is only corresponding to the magnetic field change formed by the nuclear spin polarization, the resonance frequency difference of the outer electrons before and after overturning is measured by adopting an electron paramagnetic resonance mode, and the nuclear spin polarizability is determined by utilizing the resonance frequency difference.
The method for measuring the nuclear polarizability by the atomic spin gyroscope comprises the following steps:
step 1, heating an alkali metal gas chamber in an atomic spinning gyroscope to a working temperature, and compensating a magnetic field by adopting a magnetic field cross modulation compensation technology when atoms in the alkali metal gas chamber are polarized to a stable state by laser so as to enable the gyroscope to work at a gyroscope compensation point;
step 2, opening the electron paramagnetic resonance radio frequency coil, generating a radio frequency range capable of covering the electron ground state Zeeman energy level of the outermost layer of the alkali metal element at the outer magnetic field splitting interval, scanning the radio frequency field frequency generated by the radio frequency coil from small to large or from large to small, and recording the radio frequency f when the alkali metal gas chamber emits the strongest fluorescence1；
Step 3, opening the heat-insulating fast channel coil, constructing a quantum heat-insulating fast channel, and turning the spin polarization direction of the atomic nuclei in the alkali metal gas chamber through the quantum heat-insulating fast channel;
step 4, repeating the operation of step 2, and recording the nuclear spin poleChange the radio frequency f when the alkali metal air chamber after the direction reversal sends out the strongest fluorescence2；
And 5, obtaining the spin polarizability of the nuclei by using the following formula:
Figure BDA0002796319950000021
in the formula, C is a dimensionless constant, and is related to the shape of the gas cell, and is constant when the shape is fixed. geKnown quantity of g factor, μ, of electron eBIs Bohr magneton, I is atomic nuclear spin quantum number,
Figure BDA0002796319950000022
is the Planck constant, k0Is a dimensionless constant, μ, depending on the temperature and the type of alkali metalatomIs the magnetic moment of the nucleus, natomIs the particle number concentration of the nucleus, PatomIs the nuclear spin polarizability of the nucleus.
Alkali metal air chamber is located and is equipped with the shielding section of thick bamboo center of manganese zinc ferrite ring, be provided with three-dimensional magnetic field coil in the manganese zinc ferrite ring, the alkali metal air chamber with from interior and set gradually EPR coil and AFP coil outward between the three-dimensional magnetic field coil, AFP coil connection AFP signal generator, EPR coil connection EPR signal generator, the side of alkali metal air chamber is provided with the second photoelectric detector, the photic side of alkali metal air chamber loops through 1/4 wave plate, the group of lenses of expanding the beam, polarization beam splitter prism, 1/2 wave plate, steady power executor and polarizer connection pumping laser.
The polarization beam splitter prism is connected with an electronic control unit through a first photoelectric detector, and the power stabilizing actuator is connected with the electronic control unit.
EPR signal generator connects frequency meter and attenuator respectively, feedback controller is connected to the attenuator, feedback controller connects phase-locked amplifier and EPR controller respectively, phase-locked amplifier connects respectively second photoelectric detector with the EPR controller.
The invention has the following technical effects: the invention relates to a method for measuring the nuclear polarizability of an atomic spin gyroscope based on an adiabatic fast channel, which is characterized in that the macroscopic polarization direction of a nucleus of the atomic spin gyroscope is in the same direction as polarized pump light when the atomic gyroscope works, a quantum adiabatic fast channel is constructed at the moment, the macroscopic polarization direction of the nucleus is turned over, the magnetic field change sensed by electrons on the outer layer of an alkali metal atom is only caused by the magnetic field change formed by the polarized magnetic moment of the nucleus, the change of the electron resonance frequency before and after turning over is measured by adopting an electron paramagnetic resonance mode at the moment, and the nuclear polarizability of the atom of the atomic gyroscope can be accurately measured in an in-situ lossless manner in real time. Meanwhile, the method adopts gas chamber fluorescence, namely detection, not only adds a new detection means, but also gets rid of dependence on a detection light closed-loop control light path and a detection light closed-loop control circuit, reduces the complexity of the system, is beneficial to miniaturization of the gyroscope and accurate control of the nuclear polarizability in a closed loop, and can further optimize the background magnetic field size and gradient of the atomic gyroscope on the basis of the nuclear polarizability.
The principle of the invention is as follows: the electron paramagnetic resonance frequency of the alkali metal atoms in the atomic gyroscope can be used for measuring the polarization rate of atomic nuclei, mainly the frequency shift of the Zeeman energy level of the alkali metal atoms is influenced by a magnetic field formed after the atomic nuclei are polarized, and the physical quantity related to the electron paramagnetic resonance frequency of the alkali metal atoms can be obtained by researching the evolution equation of the density matrix rho of the alkali metal along with time. Density matrix ρ and polarizability of nuclei PatomHaving a determined correspondence.
Drawings
FIG. 1 is a schematic flow chart of a method for measuring the nuclear polarizability based on an adiabatic fast channel atomic spin gyroscope. Fig. 1 includes the following steps: step 1, when an atomic gyroscope works, the nuclear spin macroscopic polarization direction is generally consistent with the emitting direction of pump light, a quantum heat insulation rapid channel is constructed, and the nuclear macroscopic polarization direction is turned over; and 2, according to the fact that the magnetic field change sensed by electrons at the outermost layer of the alkali metal atoms is only the magnetic field change formed by nuclear polarization in the whole process, the electron paramagnetic resonance mode is adopted to measure the change of the electron resonance frequency before and after overturning, and the nuclear polarization rate of the atomic gyroscope can be accurately measured in real time in an in-situ lossless mode, so that the dependence on an atomic gyroscope detection optical path system is eliminated, the complexity of the system is reduced, and the atomic gyroscope is beneficial to miniaturization and closed-loop accurate control of the nuclear polarization rate.
FIG. 2 is another schematic flow chart of the method for measuring the nuclear polarizability based on the adiabatic fast channel atomic spin gyroscope. Fig. 2 includes the following steps: step 1, heating an alkali metal gas chamber of a gyroscope to a working temperature, compensating a magnetic field by adopting a magnetic field cross modulation compensation technology, and enabling the gyroscope to work at a gyroscope compensation point; step 2, opening a radio frequency coil of electron paramagnetic resonance, setting a proper radio frequency scanning range RF, scanning a radio frequency magnetic field from small to large (or from large to small), and recording the radio frequency f _1 when the fluorescence is strongest; step 3, opening a coil of the heat insulation fast channel, inputting proper parameters to construct the heat insulation fast channel, and turning the spin polarization direction of the atomic nucleus; step 4, opening a radio frequency coil of electron paramagnetic resonance, setting a proper radio frequency scanning range RF, scanning a radio frequency magnetic field from small to large (or from large to small), and recording the radio frequency f _2 when the fluorescence is strongest; step 5, reversing the spin polarization direction of the atomic nuclei again, and recording the radio frequency f _0 when the fluorescence is strongest; and accurately calculating the polarizability of the nuclei by using a corresponding formula.
FIG. 3 is a schematic diagram of a system architecture utilized to implement the adiabatic fast channel-based atomic spin gyroscope nuclear polarizability measurement method of the present invention.
The reference numbers are listed below: 1-pump laser; 2-a polarizer; 3-power-stabilizing actuator; 4-1/2 wave plates (half-wave plates); 5-a polarization beam splitter prism; 6-a first photodetector; 7-an electronic control unit; 8-a beam expanding lens group; 9-1/4 wave plates; 10-a shielding cylinder; 11-manganese zinc ferrite ring; 12-a three-dimensional magnetic field coil; 13-AFP coil (Adiabatic Fast Passage, quantum Adiabatic Fast Passage); 14-EPR coil (Electron paramagnetic resonance); 15-a second photodetector; 16-an AFP signal generator; 17-a lock-in amplifier; 18-an EPR controller; 19-a feedback controller; 20-an attenuator; 21-an EPR signal generator; 22-a frequency meter; 23-alkali metal gas cell.
Detailed Description
The invention is explained below with reference to the figures (fig. 1-3) and the examples.
FIG. 1 is a schematic flow chart of a method for measuring the nuclear polarizability based on an adiabatic fast channel atomic spin gyroscope. FIG. 2 is another schematic flow chart of the method for measuring the nuclear polarizability based on the adiabatic fast channel atomic spin gyroscope. FIG. 3 is a schematic diagram of a system architecture utilized to implement the adiabatic fast channel-based atomic spin gyroscope nuclear polarizability measurement method of the present invention. Referring to fig. 1 to 3, the method for measuring the nuclear polarization rate by using the atomic spin gyroscope based on the adiabatic fast channel is characterized in that the nuclear spin macroscopic polarization direction of the atomic spin gyroscope is in the same direction as the pumping light when the atomic spin gyroscope works, the nuclear spin macroscopic polarization direction is reversed by using the adiabatic fast channel, the magnetic field change sensed by the outer layer electrons of the alkali metal atoms in the alkali metal gas chamber of the atomic spin gyroscope is only corresponding to the magnetic field change formed by the nuclear spin polarization, the resonance frequency difference of the outer layer electrons before and after the reversal is measured by using the electron paramagnetic resonance mode, and the nuclear spin polarization rate is determined by using the resonance frequency difference.
The method for measuring the nuclear polarizability by the atomic spin gyroscope comprises the following steps: step 1, heating an alkali metal gas chamber in an atomic spinning gyroscope to a working temperature, and compensating a magnetic field by adopting a magnetic field cross modulation compensation technology when atoms in the alkali metal gas chamber are polarized to a stable state by laser so as to enable the gyroscope to work at a gyroscope compensation point; step 2, opening the electron paramagnetic resonance radio frequency coil, generating a radio frequency range capable of covering the electron ground state Zeeman energy level of the outermost layer of the alkali metal element at the outer magnetic field splitting interval, scanning the radio frequency field frequency generated by the radio frequency coil from small to large or from large to small, and recording the radio frequency f when the alkali metal gas chamber emits the strongest fluorescence1(ii) a Step 3, opening the heat-insulating fast channel coil, constructing a quantum heat-insulating fast channel, and turning the spin polarization direction of the atomic nuclei in the alkali metal gas chamber through the quantum heat-insulating fast channel; and 4, repeating the operation of the step 2, and recording the most emitted alkali metal gas chamber after the spin polarization direction of the atomic nuclei is reversedRadio frequency f in intense fluorescence2(ii) a And 5, obtaining the spin polarizability of the nuclei by using the following formula:
Figure BDA0002796319950000051
in the formula, C is a dimensionless constant, and is related to the shape of the gas cell, and is constant when the shape is fixed. geKnown quantity of g factor, μ, of electron eBIs Bohr magneton, I is atomic nuclear spin quantum number,
Figure BDA0002796319950000052
is the Planck constant, k0Is a dimensionless constant, μ, depending on the temperature and the type of alkali metalatomIs the magnetic moment of the nucleus, natomIs the particle number concentration of the nucleus, PatomIs the nuclear spin polarizability of the nucleus.
Referring to fig. 3, alkali metal air chamber 23 is located and is equipped with the shielding section of thick bamboo 10 center of manganese zinc ferrite ring 11 in, be provided with three-dimensional magnetic field coil 12 in the manganese zinc ferrite ring 11, alkali metal air chamber 23 with from interior and AFP coil 13 that has set gradually between the three-dimensional magnetic field coil 12, AFP coil 13 connects AFP signal generator 16, EPR signal generator 21 is connected to EPR coil 14, the side of alkali metal air chamber 23 is provided with second photoelectric detector 15, the photic side of alkali metal air chamber 23 loops through 1/4 wave plate 9, expands beam lens group 8, polarization beam splitter prism 5, 1/2 wave plate 4, steady power executor 3 and polarizer 2 and connects pumping laser 1. The polarization beam splitter prism 5 is connected with an electronic control unit 7 through a first photoelectric detector 6, and the power stabilizing actuator 3 is connected with the electronic control unit 7. EPR signal generator 21 connects frequency meter 22 and attenuator 20 respectively, feedback controller 19 is connected to attenuator 20, phase-locked amplifier 17 and EPR controller 18 are connected respectively to feedback controller 19, phase-locked amplifier 17 connects respectively second photoelectric detector 15 with EPR controller 18.
A method for accurately measuring the polarizability of nuclei of an atomic gyroscope during online working is characterized by comprising the following steps:
(1) heating an alkali metal gas chamber of a gyroscope to a working temperature, compensating a magnetic field by adopting a magnetic field cross modulation compensation technology when the laser polarizes atoms to a stable state, and working the gyroscope at a gyroscope compensation point;
(2) opening a radio frequency coil for electron paramagnetic resonance, scanning the frequency of a radio frequency field, scanning from small to large (or from large to small), and recording the working frequency f _1 of the radio frequency coil when the fluorescence is strongest;
(3) opening a coil for generating an adiabatic fast channel, inputting proper parameters to construct the adiabatic fast channel, and turning the spin polarization direction of atomic nuclei;
(4) repeating the operation in the step (2), and recording the working frequency f _2 of the radio frequency coil when the fluorescence is strongest;
(5) and (3) repeating the steps (3) and (2), recording the working frequency f _0 of the radio frequency coil when the fluorescence is strongest, and finishing the online measurement of the spin polarization of the gyroscope nuclei.
And recording different fluorescence light intensities along with the change of the working frequency of the radio frequency coil, and recording the radio frequency value when the fluorescence light intensity is strongest. Proper parameters are input into the heat insulation fast channel coil to construct a heat insulation fast channel and realize the inversion of the spin polarization direction of the atomic nucleus.
A method for measuring the polarizability of nuclear based on an adiabatic fast channel atomic spin gyroscope is realized by the following steps: (1) heating an alkali metal gas chamber of a gyroscope to a working temperature, compensating a magnetic field by adopting a magnetic field cross modulation compensation technology when the laser polarizes atoms to a stable state, and working the gyroscope at a gyroscope compensation point; (2) opening a radio frequency coil for electron paramagnetic resonance, generating a radio frequency range which can cover the electron ground state Zeeman energy level at the outermost layer of the alkali metal element at the outer magnetic field splitting interval, scanning the radio frequency field frequency generated by the radio frequency coil from small to large (or from large to small), and recording the radio frequency f _1 when the fluorescence is strongest; (3) opening a coil for generating an adiabatic fast channel, inputting proper parameters to construct the adiabatic fast channel, and turning the spin polarization direction of atomic nuclei; (4) repeating the operation in the step (2), and recording the working frequency f _2 of the radio frequency coil when the fluorescence is strongest; (5) and (3) repeating the steps (3) and (2), recording the working frequency f _0 of the radio frequency coil when the fluorescence is strongest, and finishing the online measurement of the spin polarization of the nuclei by the gyroscope at the moment. (6) The above-mentioned frequency values are substituted into the following formula,
f2-f1＝2Δv (1)
Figure BDA0002796319950000061
where C is a dimensionless constant associated with the shape of the chamber, which is constant when the shape is fixed. geG factor of electrons, μBIs Bohr magneton, I is atomic nuclear spin quantum number,
Figure BDA0002796319950000062
is the Planck constant, k0Is a dimensionless constant, depending on the temperature and the type of alkali metal, muatomIs the magnetic moment of the corresponding nucleus, natomIs the particle number concentration of the corresponding nucleus, PatomIs the polarizability of the nuclei. The polarizability of the corresponding nuclei can be accurately calculated.
The principle of the invention is as follows: the electron paramagnetic resonance frequency of the alkali metal atoms in the atomic gyroscope can be used for measuring the polarization rate of atomic nuclei, mainly the frequency shift of the Zeeman energy level of the alkali metal atoms is influenced by a magnetic field formed after the atomic nuclei are polarized, and the physical quantity related to the electron paramagnetic resonance frequency of the alkali metal atoms can be obtained by researching the evolution equation of the density matrix rho of the alkali metal along with time:
Figure BDA0002796319950000071
wherein A is the hyperfine constant of the alkali metal,
Figure BDA0002796319950000075
is an alkali metal nuclear spin operator and is,
Figure BDA0002796319950000076
is an alkali metal electron spin operator, ωeAnd ωIZeeman frequencies, K, of electrons and nuclei, respectivelySEIs the spin exchange rate, Γ, of the alkali metal electron spin and the working nuclear spinSEIs a parameter of the frequency shift and,
Figure BDA0002796319950000079
is the nuclear spin of the working nuclei, alpha,
Figure BDA00027963199500000710
is an operator of the spin of the alkali metal nuclei,
Figure BDA0002796319950000072
other factors which are not related to the working nucleus but have influence on the time-dependent evolution of the density matrix, such as alkali metal-to-metal spin exchange, optical pumping process and the like. In the above formula contain
Figure BDA00027963199500000711
The two terms of (1) are main reasons for the Zeeman frequency shift of the alkali metal atoms caused by the working nuclei, and comprise a real part term and an imaginary part term, wherein the real part term can affect the Zeeman frequency shift of the alkali metal only after a second-order effect, and the effect can be ignored relative to the imaginary part term, so that only the effect generated by the imaginary part term is considered.
When the direction of polarization of the working nuclei is taken into account along the Z-axis, i.e.
Figure BDA0002796319950000073
The effect of the imaginary part on the zeeman shift can now be equated to a superimposed magnetic field:
BSE＝(2ΓSEKSEh/geμB)Kz (4)
the resulting EPR frequency shift is:
Figure BDA0002796319950000074
produced by polarising working atomic nucleiThe classical magnetic field also has an influence on the paramagnetic resonance frequency of the alkali metal, and the equivalent field strength BMThe magnitude is proportional to the magnetic moment M of the working atomic nucleus, which has the value:
BM＝C·M (6)
wherein C is a dimensionless constant related to the shape of the working chamber. The magnetic moment of the nucleus of the working atom can be written as:
M＝μatom·natomPatom (7)
wherein muatomIs the magnetic moment of the nucleus of the working atom, natomIs the density of the nuclei of the working atoms in units of Amagat (pressure of the working atomic gas at 0 ℃, 1Amagat or 1amg ═ 2.69 × 10)19cm-3is the density of an ideal gas at standard temperature and pressure)，PatomIs the nuclear polarizability of the working nuclei. The EPR frequency shift for this corresponding alkali electron is:
Figure BDA0002796319950000081
the frequency shift in both cases is proportional to the polarizability and density of the working atomic nuclei, so that a dimensionless constant k, which is dependent only on temperature and alkali metal species, can be redefined0Will KSEAlso included, the correspondence between frequency shift and polarization of the working nuclei can be obtained:
Figure BDA0002796319950000082
to measure the value of Δ v, the direction of the nuclear spin polarization of the working nuclei needs to be reversed. The EPR frequencies before and after inversion were measured separately with a difference of 2 Δ v. At the moment, the corresponding polarization rate of the working atomic nuclei can be accurately calculated. Taking a spherical gas cell as an example, equation 9 can be calculated:
Figure BDA0002796319950000083
compared with the prior art, the invention has the advantages that: in general, measurement is performed by using Free Induced Decay (FID), which requires applying a step magnetic field in a direction transverse to the polarization of a nuclear nucleus, detecting a precession signal of a nuclear magnetic moment under the magnetic field, and obtaining the relative strength of the polarization of the nuclear nucleus through the nuclear magnetic moment precession signal. However, such a detection method has the following disadvantages: 1. the influence of the background noise of the transverse magnetic field on the detection result cannot be shielded; 2. only the proportional change of the nuclear spin polarization intensity can be obtained, and the nuclear spin polarization intensity cannot be accurately measured; 3. the detection light is introduced for indirect measurement, and various noises in the detection process are inevitably coupled; 4. the FID measurement is non-nondestructive every time, and the online real-time measurement cannot be realized. The problems can cause that the nuclear spin polarization can not be accurately measured, and meanwhile, the closed-loop control of the nuclear spin polarization strength can not be realized, so that the fixed axis type of the gyroscope can not be controlled in a closed-loop manner, and the zero-offset stability of the gyroscope is poor. The method comprises the steps of utilizing a quantum thermal insulation process to turn the macroscopic polarization direction of the nucleus, wherein the magnetic field change sensed by outer electrons of alkali metal atoms is only caused by the magnetic field change formed by the polarization of the nucleus, and the change of the electron resonance frequency before and after turning is measured in an electron paramagnetic resonance mode, so that the nuclear polarization rate of the atomic gyroscope during online work can be accurately measured in a real-time in-situ lossless manner. Meanwhile, the method can enable the atomic gyroscope to be detected only by adopting gas chamber fluorescence, adds a new detection means, gets rid of dependence on a detection light closed-loop control light path and a detection light closed-loop control circuit, reduces the system complexity, is beneficial to the miniaturization of the gyroscope and the closed-loop accurate control of the nuclear polarizability, and can further optimize the background magnetic field size and the gradient of the atomic gyroscope on the basis.
The method comprises the following specific implementation steps:
(1) the gyroscope alkali metal gas chamber 23 is heated to the working temperature, a beam of circularly polarized pumping light polarizes alkali metal electrons, the alkali metal electrons polarize inert gas nuclei through spin exchange, when the nuclei polarize to a stable state, a magnetic field cross modulation compensation technology is adopted to compensate the magnetic field, and at the moment, the gyroscope works at a gyroscope compensation point. The light output by the pumping laser 1 passes through a power stabilizing system consisting of a polarizer 2, a power stabilizing actuator 3, an 1/2 glass slide 4, a polarization beam splitter prism 5, a photoelectric detector 6 and an electronic control unit 7, so that power closed-loop control is realized. Then converted into circularly polarized light with the spot diameter equal to the diameter of the air chamber through the beam expanding lens group 8 and 1/4 slide glass 9. An alkali metal gas chamber 23 is installed inside the shield cylinder 10 and the manganese-zinc ferrite ring 11. Around the gas cell, there are distributed three-dimensional magnetic field coils 12, An (AFP) coil 13 for creating quantum Adiabatic channels, an (EPR) coil 14 for Electron paramagnetic resonance detection, and a photodetector 15 placed around the gas cell 23 for detecting fluorescence information.
(2) The EPR controller 18 is turned on, signals are sent to the phase-locked amplifier 17 and the feedback controller 19, the signals are input into the EPR signal generator 20 after passing through the attenuator 20, the EPR coil 14 generates a corresponding radio frequency magnetic field, the radio frequency magnetic field is scanned within the range of the radio frequency magnetic field, the radio frequency magnetic field is scanned from small to large (or from large to small), and the radio frequency f _1 when the fluorescence is strongest is recorded by the frequency meter 22;
(3) and opening an AFP signal generator 16 to generate a quantum adiabatic channel and turn the polarization direction of the atomic nucleus.
(4) Closing the AFP coil controller, repeating the step (2), and recording the radio frequency f _2 with the strongest fluorescence;
(5) and (4) repeating the step (3) again to open the quantum adiabatic channel and restore the polarization direction of the atomic nucleus. Meanwhile, repeating the step (2) and recording the radio frequency f _0 when the fluorescence is strongest;
finally, the frequency value is substituted into the following formula:
f2-f1＝2Δv
Figure BDA0002796319950000091
thus completing the measurement of the polarizability of the atomic nucleus.
Those skilled in the art will appreciate that the invention may be practiced without these specific details. It is pointed out here that the above description is helpful for the person skilled in the art to understand the invention, but does not limit the scope of protection of the invention. Any such equivalents, modifications and/or omissions as may be made without departing from the spirit and scope of the invention may be resorted to.

Claims (2)

1. The method for measuring the nuclear polarizability of the atomic spin gyroscope based on the adiabatic fast channel is characterized in that the nuclear spin macroscopic polarization direction of the atomic spin gyroscope is in the same direction as pump light when the atomic spin gyroscope works, the nuclear spin macroscopic polarization direction is overturned by the adiabatic fast channel, so that the magnetic field change sensed by outer electrons of alkali metal atoms in an alkali metal gas chamber of the atomic spin gyroscope is only corresponding to the magnetic field change formed by the nuclear spin polarization, the resonance frequency difference of the outer electrons before and after overturning is measured by adopting an electron paramagnetic resonance mode, and the nuclear spin polarizability is determined by utilizing the resonance frequency difference.
2. The adiabatic fast channel-based atomic spin gyroscope measuring nuclear polarizability method of claim 1, wherein the atomic spin gyroscope measuring nuclear polarizability method comprises the steps of:
step 1, heating an alkali metal gas chamber in an atomic spinning gyroscope to a working temperature, and compensating a magnetic field by adopting a magnetic field cross modulation compensation technology when atoms in the alkali metal gas chamber are polarized to a stable state by laser so as to enable the gyroscope to work at a gyroscope compensation point;
step 2, opening the electron paramagnetic resonance radio frequency coil, generating a radio frequency range capable of covering the electron ground state Zeeman energy level of the outermost layer of the alkali metal element at the outer magnetic field splitting interval, scanning the radio frequency field frequency generated by the radio frequency coil from small to large or from large to small, and recording the radio frequency f when the alkali metal gas chamber emits the strongest fluorescence1；
Step 3, opening the heat-insulating fast channel coil, constructing a quantum heat-insulating fast channel, and turning the spin polarization direction of the atomic nuclei in the alkali metal gas chamber through the quantum heat-insulating fast channel;
step 4, repeating the operation of the step 2, and recording the radio frequency f when the alkali metal gas chamber with the reversed nuclear spin polarization direction emits the strongest fluorescence2；
And 5, obtaining the spin polarizability of the nuclei by using the following formula:
Figure FDA0002796319940000011
in the formula, C is a dimensionless constant, and is related to the shape of the gas cell, and is constant when the shape is fixed. geKnown quantity of g factor, μ, of electron eBIs Bohr magneton, I is atomic nuclear spin quantum number,
Figure FDA0002796319940000012
is the Planck constant, k0Is a dimensionless constant, μ, depending on the temperature and the type of alkali metalatomIs the magnetic moment of the nucleus, natomIs the particle number concentration of the nucleus, PatomIs the nuclear spin polarizability of the nucleus.
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