A resonant dual-axis SERF atomic spin gyroscope based on pump light modulation

Abstract

The present invention relates to the technical field of SERF atomic spin gyroscopes, and discloses a resonant dual-axis SERF atomic spin gyroscope based on pump light modulation, which realizes the SERF state by manipulating the atomic ensemble to operate in a high temperature and weak magnetic environment. A beam of pump light modulated by the electron resonance frequency is used to realize electron resonance through an alkali metal gas chamber. Another beam of detection laser is used to extract the atomic spin precession signal through the alkali metal gas chamber, and then the optical rotation angle signal generated by the atoms in the gas chamber is extracted through a polarization-balanced beam splitting optical path. The optical rotation angle signal is converted into an electrical signal and input into a phase-locked amplifier. The phase-locked amplifier uses orthogonal demodulation with reference to the modulation frequency of the modulated pump light to realize dual-axis signal output. The present invention utilizes a beam of pump light modulated by the electron resonance frequency to manipulate the atomic ensemble to realize electron resonance, thereby improving the signal-to-noise ratio and precision of the atomic spin gyroscope, and simultaneously realizing the output of dual-axis signals by a single beam of detection light, which is conducive to the development of miniaturized and high-precision SERF atomic spin gyroscopes.

Description

Technical Field

[0001] The present invention relates to the technical field of SERF atomic spin gyroscopes, and in particular to a resonant dual-axis SERF atomic spin gyroscope based on pump light modulation. Background Art

[0002] Spin-exchange relaxation-free (SERF) atomic spin gyroscopes have the potential to achieve ultra-high precision while being miniaturized. They are widely used in scientific discoveries in basic research and technological innovations in engineering research, and have become one of the research hotspots in high-precision inertial measurement systems.

[0003] However, traditional SERF atomic spin gyroscopes still have some shortcomings in practical applications. Traditional SERF atomic spin gyroscopes use direct current mode or magnetic field modulation mode to achieve inertial measurement, which does not excite the electronic resonance of the atomic ensemble. This results in low output signal intensity and a low signal-to-noise ratio. This limits the measurement accuracy and stability of the gyroscope in practical applications. In addition, low-frequency noise has a significant impact on traditional SERF atomic spin gyroscopes, easily causing drift and distortion of the measurement signal, seriously affecting the reliability and accuracy of the measurement. Although SERF atomic spin gyroscopes based on magnetic field modulation effectively suppress low-frequency noise, they also introduce magnetic noise to a certain extent, which is not conducive to improving the accuracy and stability of the gyroscope. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a resonant dual-axis SERF atomic spin gyroscope based on pump light modulation. A beam of pump light modulated by the electron resonance frequency is used to manipulate the atomic ensemble to achieve electronic resonance, thereby enhancing the output signal, improving the signal-to-noise ratio, and effectively suppressing the influence of low-frequency noise. Dual-axis signal decoupling is then achieved through orthogonal demodulation by a phase-locked amplifier, which is conducive to the development of miniaturized and high-precision SERF atomic spin gyroscopes.

[0005] To achieve the above objectives, the present invention provides a resonant dual-axis SERF atomic spin gyroscope based on pump light modulation, comprising an atomic gas chamber, a non-magnetic temperature control system, a three-axis active magnetic compensation coil, a passive magnetic shielding system, an optical pumping system, a detection system, and a circuit system;

[0006] The atomic gas chamber is a sensitive core, and the interior of the atomic gas chamber is filled with alkali metal atoms and inert gas;

[0007] The non-magnetic temperature control system heats the atomic gas chamber to the operating temperature and maintains the temperature stability;

[0008] The passive magnetic shielding system is used to shield the atomic gas chamber from external magnetic fields, and the atomic gas chamber is located within the passive magnetic shielding system;

[0009] The three-axis active magnetic compensation coil performs active residual magnetic compensation on the residual magnetism in the passive magnetic shielding system and adjusts the gyroscope to a nuclear spin self-compensation state;

[0010] The optical pumping system generates a beam of pumping light modulated by the electron resonance frequency, wherein the pumping light is circularly polarized light, which is used to polarize the atoms in the atomic gas cell and achieve electron resonance;

[0011] The detection system is used to generate detection light perpendicular to the pumping direction. The detection light is linearly polarized light and is used to detect atomic spin precession signals.

[0012] Preferably, the circuit system includes a driving module and a phase-locked amplification module. On the one hand, the driving module drives the three-axis active magnetic compensation coil to actively compensate for the residual magnetism in the passive magnetic shielding system. On the other hand, it is used to generate a carrier signal with an electronic resonance frequency and apply it to the optical modulation module of the optical pumping system to optically modulate the pumping light to obtain pumping light carrying modulation information. The phase-locked amplification module is used to extract the transverse two-axis angular rate signals Ωx and Ωy from the precession signal and output them.

[0013] Preferably, the driving module includes a three-axis coil driving module and an optical modulation driving module, the three-axis coil driving module includes a module for applying magnetic fields Bx, By, and Bz along the X, Y, and Z axes respectively, the optical modulation driving module is used to generate a carrier signal of an electronic resonance frequency, and the phase-locked amplifier module has a signal input terminal, a reference angular frequency input terminal connected to the optical modulation driving module, and Ωx ​​and Ωy signal output terminals.

[0014] Preferably, the optical pumping system comprises a first laser, an optical modulation module, a first beam expander, a first laser power frequency control module and a λ / 4 wave plate optically connected in sequence;

[0015] The first laser emits a pumping laser, which is converted into modulated circularly polarized light by the optical modulation module, the first beam expander, and the first laser power frequency control module, and then by the λ / 4 wave plate, and then passes through the atomic gas cell to achieve the preparation and manipulation of the polarization state of the atomic ensemble;

[0016] The optical modulation module is one of an acousto-optic modulator, a magneto-optic modulator, an electro-optic modulator, and an optical attenuator.

[0017] Preferably, the detection system includes a second laser, a second beam expander, a second laser power frequency control module, a λ / 2 wave plate, a polarization beam splitter prism, a first photodetector, a second photodetector, and a differential detector optically connected in sequence; the atomic gas chamber is located between the second laser power frequency control module and the λ / 2 wave plate; the second detection laser emits a detection laser, which is converted into linearly polarized light by the second beam expander and the second laser power frequency control module, and passes through the atomic gas chamber in a direction perpendicular to the pumping light to achieve extraction of the atomic spin precession signal; the laser light passing through the gas chamber rotates its initial linear polarization plane by 45° by the λ / 2 wave plate, and then passes through the polarization beam splitter prism, the first photodetector, the second photodetector, and the differential detector to form a polarization balance differential module to extract the optical rotation angle signal generated in the gas chamber;

[0018] The operating frequency of the detection laser is detuned from the resonance peak of the atom to reduce the absorption of the laser by the atom and enhance the optical rotation angle signal.

[0019] Preferably, the electronic resonance frequency ω is expressed as follows:

[0020]

[0021] where γ e is the gyromagnetic ratio of alkali metal electrons, Q is the slowing factor, B e is the Fermi contact magnetic field generated by the spin polarization of alkali metal electrons, L z is the z-axis optical frequency shift.

[0022] Preferably, the x-axis angular rate Ωx and the y-axis angular rate Ωy in the transverse biaxial angular rate are extracted from the following expressions:

[0023]

[0024] is the AC component of the alkali metal electron polarization vector along the x-axis, Q is the slowing factor, R p0 is the steady-state optical pumping rate, γ e and γ n are the gyromagnetic ratios of alkali metal electrons and noble gas nuclei, is the total relaxation rate of alkali metal electrons, B e is the Fermi contact magnetic field generated by the spin polarization of alkali metal electrons, L z is the z-axis optical frequency shift.

[0025] The technical effects of the present invention are as follows: The present invention provides a resonant dual-axis SERF atomic spin gyroscope based on pump light modulation, which uses an alkali metal and an inert gas atomic ensemble as sensitive media, and realizes the SERF state by manipulating the atomic ensemble to work in a high temperature and weak magnetic environment. A beam of pump light modulated by the electron resonance frequency is emitted to the atomic ensemble through an alkali metal gas chamber, so that the atomic ensemble has a macroscopic direction in the inertial space, realizes electron resonance, enhances the output signal, and suppresses the influence of low-frequency noise on the system accuracy. Another beam of detection laser perpendicular to the pumping direction is used to extract the atomic spin precession signal through the alkali metal gas chamber, and then extracts the optical rotation angle signal generated by the atoms in the gas chamber through a polarization-balanced beam splitting optical path. The optical rotation angle signal is converted into an electrical signal by a differential detector and input into a phase-locked amplifier. The phase-locked amplifier uses orthogonal demodulation to realize dual-axis signal output with reference to the modulation frequency of the modulated pump light.

[0026] The advantages of the present invention over the prior art are as follows: the present invention provides a resonant dual-axis SERF atomic spin gyroscope based on pump light modulation, which utilizes a beam of pump light modulated by the electron resonance frequency to manipulate the atomic ensemble to achieve alkali metal electron resonance, thereby enhancing the output signal and suppressing low-frequency noise, thereby improving the signal-to-noise ratio and precision of the atomic spin gyroscope. At the same time, a single beam of detection light can be used to output a dual-axis signal, which is conducive to the development of miniaturized and high-precision SERF atomic spin gyroscopes.

[0027] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic structural diagram of a resonant dual-axis SERF atomic spin gyroscope based on pump light modulation according to the present invention;

[0029] Reference numerals

[0030] 1. Atomic gas chamber; 2. Non-magnetic temperature control system; 3. Three-axis active magnetic compensation coil; 4. Passive magnetic shielding system; 5. Optical pumping system; 51. First laser; 52. Optical modulation module; 53. First beam expander; 54. First laser power frequency control module; 55. λ / 4 wave plate; 6. Detection system; 61. Second laser; 62. Second beam expander; 63. Second laser power frequency control module; 64. λ / 2 wave plate; 65. Polarization beam splitter; 66. First photodetector; 67. Second photodetector; 68. Differential detector; 7. Circuit system; 71. Drive module; 72. Phase-locked amplifier module; XYZ, coordinate axis; Ch1, provide reference signal for optical modulation module; Ch2, apply magnetic field along x-axis; Ch3, apply magnetic field along y-axis; Ch4, apply magnetic field along z-axis. DETAILED DESCRIPTION

[0031] The present invention will be described below with reference to the accompanying drawings and embodiments.

[0032] Figure 1 FIG. 1 is a schematic structural diagram of a resonant dual-axis SERF atomic spin gyroscope based on pump light modulation according to the present invention. Figure 1 As shown, an embodiment of the present invention provides a resonant dual-axis SERF atomic spin gyroscope based on pump light modulation, including an atomic gas chamber 1, a non-magnetic temperature control system 2, a three-axis active magnetic compensation coil 3, a passive magnetic shielding system 4, an optical pumping system 5, a detection system 6 and a circuit system 7; the atomic gas chamber 1 is a sensitive core, and the interior of the atomic gas chamber 1 is filled with alkali metal atoms and an inert gas; the non-magnetic temperature control system 2 heats the atomic gas chamber 1 to an operating temperature and maintains temperature stability; the passive magnetic shielding system 4 is used to shield the atomic gas chamber 1 from the external magnetic field, and the atomic gas chamber 1 is located in the passive magnetic shielding system 4; the three-axis active magnetic compensation coil 3 actively compensates for the residual magnetism in the passive magnetic shielding system 4 and adjusts the gyroscope to a nuclear spin self-compensation state; the optical pumping system 5 generates a beam of pumping light modulated by the electron resonance frequency, and the pumping light is circularly polarized light, which is used to polarize the atoms in the atomic gas chamber 1 and realize electron resonance; the detection system 6 is used to generate detection light perpendicular to the pumping direction, and the detection light is linearly polarized light, which is used to detect atomic spin precession signals.

[0033] The circuit system 7 includes a drive module 71 and a phase-locked amplifier module 72. The drive module 71 drives the three-axis active magnetic compensation coil 3 to actively compensate for the residual magnetism in the passive magnetic shielding system 4. On the other hand, it is used to generate a carrier signal of the electron resonance frequency and apply it to the optical modulation module 52 of the optical pumping system 5 to optically modulate the pumping light to obtain pumping light carrying modulation information. The phase-locked amplifier module 72 is used to extract the transverse two-axis angular rate signals Ωx and Ωy from the precession signal and output them.

[0034] The driving module 71 includes a three-axis coil driving module and an optical modulation driving module. The three-axis coil driving module includes a module for applying magnetic fields Bx, By, and Bz along the X, Y, and Z axes respectively. The optical modulation driving module is used to generate a carrier signal of an electronic resonance frequency. The phase-locked amplifier module 72 has a phase-locked amplifier module signal input terminal, a reference angular frequency input terminal connected to the optical modulation driving module, and Ωx ​​and Ωy signal output terminals.

[0035] The optical pumping system 5 includes a first laser 51 , an optical modulation module 52 , a first beam expander 53 , a first laser power frequency control module 54 and a λ / 4 wave plate 55 , which are optically connected in sequence.

[0036] The first laser 51 emits a pumping laser, which passes through the optical modulation module 52, the first beam expander 53 and the first laser power frequency control module 54, and then is converted into modulated circularly polarized light through the λ / 4 wave plate 55, and passes through the atomic gas chamber 1 to realize the preparation and manipulation of the polarization state of the atomic ensemble.

[0037] The optical modulation module 52 is one of an acousto-optic modulator, a magneto-optic modulator, an electro-optic modulator, and an optical attenuator.

[0038] The detection system 6 includes a second laser 61, a second beam expander 62, a second laser power frequency control module 63, a λ / 2 wave plate 64, a polarization beam splitter 65, a first photodetector 66, a second photodetector 67, and a differential detector 68, which are optically connected in sequence. The atomic gas cell 1 is located between the second laser power frequency control module 63 and the λ / 2 wave plate 64. The second detection laser 61 emits a detection laser, which is converted into linearly polarized light by the second beam expander 62 and the second laser power frequency control module 63. The detection laser passes through the atomic gas cell 1 in a direction perpendicular to the pumping light to extract the atomic spin precession signal. The laser light passing through the gas cell rotates its initial linear polarization plane by 45° by the λ / 2 wave plate 64, and then passes through the polarization beam splitter prism 65, the first photodetector 66, the second photodetector 67, and the differential detector 68 to form a polarization balance differential module to extract the optical rotation angle signal generated in the gas cell.

[0039] The operating frequency of the detection laser is detuned from the resonance peak of the atom to reduce the absorption of the laser by the atom and enhance the optical rotation angle signal.

[0040] The electron resonance frequency ω is expressed as follows:

[0041]

[0042] where γ e is the gyromagnetic ratio of alkali metal electrons, Q is the slowing factor, B e is the Fermi contact magnetic field generated by the spin polarization of alkali metal electrons, L z is the z-axis optical frequency shift.

[0043] The x-axis angular rate Ωx and the y-axis angular rate Ωy in the transverse two-axis angular rate are extracted from the following expressions:

[0044]

[0045] is the AC component of the alkali metal electron polarization vector along the x-axis, Q is the slowing factor, R p0 is the steady-state optical pumping rate, γ e and γ n are the gyromagnetic ratios of alkali metal electrons and noble gas nuclei, is the total relaxation rate of alkali metal electrons, B e is the Fermi contact magnetic field generated by the spin polarization of alkali metal electrons, L z is the z-axis optical frequency shift.

[0046] A method for using a resonant dual-axis SERF atomic spin gyroscope based on pump light modulation includes the following steps:

[0047] Step 1: Install the resonant dual-axis SERF atomic spin gyroscope based on pump light modulation on the carrier platform, turn on the non-magnetic electric heating system, heat it to the specified temperature, turn on the three-axis active magnetic compensation coil 3, and accurately compensate the residual magnetism in the passive magnetic shielding system 4 to near zero magnetism to achieve the SERF state.

[0048] Step 2: Turn on the first laser 501 of the optical pumping system 5 and the second laser 601 of the detection system 6. Then, configure the driver module 701 of the circuit system 7 and the optical modulation module 502 of the optical pumping system 5 to achieve pump light modulation. The corresponding pumping rate can be expressed as , where is the steady-state optical pumping rate and is the electron resonance frequency. The modulated pump light gives the atomic ensemble a macroscopic orientation in inertial space, achieving electron resonance, increasing the output signal, and isolating the impact of low-frequency noise on system accuracy and stability. The detection laser extracts the atomic spin precession signal through the alkali metal gas chamber.

[0049] Step 3: After the system signal is stable, the three-axis active magnetic compensation coil 3 is used to apply a compensation magnetic field in the z direction to adjust the gyroscope to the nuclear spin self-compensation state, so that it automatically tracks the changes in the external magnetic field for magnetic field compensation.

[0050] In step 4, the detection laser extracts the optical rotation angle signal generated by the atoms in the gas chamber through the polarization-balanced beam splitting optical path. The electrical signal converted by the differential detector 608 is input into the phase-locked amplifier 702. The phase-locked amplifier 702 refers to the modulation frequency of the modulated pump light and uses orthogonal demodulation to realize the output of the dual-axis measurement signal using a single beam of detection laser.

[0051] The contents not described in detail in the specification of the present invention belong to the prior art known to those skilled in the art.

[0052] It is noted that the above description is intended to help those skilled in the art understand the present invention, but is not intended to limit the scope of protection of the present invention. Any equivalent substitution, modification, improvement, and / or simplification of the above description that does not depart from the essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A resonant dual-axis SERF atomic spin gyroscope based on pump light modulation, characterized by: It includes atomic gas chamber, non-magnetic temperature control system, three-axis active magnetic compensation coil, passive magnetic shielding system, optical pumping system, detection system and circuit system; The atomic gas chamber is a sensitive core, and the interior of the atomic gas chamber is filled with alkali metal atoms and inert gas; The non-magnetic temperature control system heats the atomic gas chamber to the operating temperature and maintains the temperature stability; The passive magnetic shielding system is used to shield the atomic gas chamber from external magnetic fields, and the atomic gas chamber is located within the passive magnetic shielding system; The three-axis active magnetic compensation coil performs active residual magnetic compensation on the residual magnetism in the passive magnetic shielding system and adjusts the gyroscope to a nuclear spin self-compensation state; The optical pumping system generates a beam of pumping light modulated by the electron resonance frequency, wherein the pumping light is circularly polarized light, which is used to polarize the atoms in the atomic gas cell and achieve electron resonance; The detection system is used to generate detection light perpendicular to the pumping direction, and the detection light is linearly polarized light, which is used to detect atomic spin precession signals; The circuit system includes a driving module and a phase-locked amplifier module. The driving module, on the one hand, drives the three-axis active magnetic compensation coil to actively compensate for the residual magnetism in the passive magnetic shielding system. On the other hand, it is used to generate a carrier signal with an electronic resonance frequency and apply it to the optical modulation module of the optical pumping system to optically modulate the pumping light to obtain pumping light carrying modulation information. The phase-locked amplifier module is used to extract and output the transverse two-axis angular rate signals Ωx and Ωy from the precession signal. The x-axis angular rate Ωx and the y-axis angular rate Ωy in the transverse biaxial angular rate are extracted from the following expressions: The polarization vector of alkali metal electrons is along AC component of the shaft, is the slowing factor, is the steady-state optical pumping rate, and are the gyromagnetic ratios of alkali metal electrons and noble gas nuclei, is the total relaxation rate of alkali metal electrons, is the Fermi contact magnetic field generated by the spin polarization of alkali metal electrons. for Axis optical frequency shift.

2. The resonant dual-axis SERF atomic spin gyroscope based on pump light modulation according to claim 1, characterized in that: The driving module includes a three-axis coil driving module and an optical modulation driving module. The three-axis coil driving module includes a module for applying magnetic fields Bx, By, and Bz along the X, Y, and Z axes respectively. The optical modulation driving module is used to generate a carrier signal of an electronic resonance frequency. The phase-locked amplifier module has a signal input terminal, a reference angular frequency input terminal connected to the optical modulation driving module, and Ωx ​​and Ωy signal output terminals.

3. The resonant dual-axis SERF atomic spin gyroscope based on pump light modulation according to claim 1, characterized in that: The optical pumping system includes a first laser, an optical modulation module, a first beam expander, a first laser power frequency control module and a λ / 4 wave plate optically connected in sequence; The first laser emits a pumping laser, which is converted into modulated circularly polarized light by the optical modulation module, the first beam expander, and the first laser power frequency control module, and then by the λ / 4 wave plate, and then passes through the atomic gas cell to achieve the preparation and manipulation of the polarization state of the atomic ensemble; The optical modulation module is one of an acousto-optic modulator, a magneto-optic modulator, an electro-optic modulator, and an optical attenuator.

4. The resonant dual-axis SERF atomic spin gyroscope based on pump light modulation according to claim 1, characterized in that: The detection system includes a second laser, a second beam expander, a second laser power frequency control module, a λ / 2 wave plate, a polarization beam splitter prism, a first photodetector, a second photodetector, and a differential detector optically connected in sequence. The atomic gas cell is located between the second laser power frequency control module and the λ / 2 wave plate. The second laser emits a detection laser, which is converted into linearly polarized light by the second beam expander and the second laser power frequency control module. The detection laser passes through the atomic gas cell in a direction perpendicular to the pumping light to extract the atomic spin precession signal. The laser light passing through the gas cell rotates its initial linear polarization plane by 45° by the λ / 2 wave plate, and then passes through the polarization beam splitter prism, the first photodetector, the second photodetector, and the differential detector to form a polarization balance differential module to extract the optical rotation angle signal generated in the gas cell. The operating frequency of the detection laser is detuned from the resonance peak of the atom to reduce the absorption of the laser by the atom and enhance the optical rotation angle signal.

5. The resonant dual-axis SERF atomic spin gyroscope based on pump light modulation according to claim 1, characterized in that: The electronic resonance frequency is expressed as follows: in is the gyromagnetic ratio of alkali metal electrons, is the slowing factor, is the Fermi contact magnetic field generated by the spin polarization of alkali metal electrons. for Axis optical frequency shift.

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