阅读说明：本技术 一种单激光器的核磁共振陀螺仪 (Single-laser nuclear magnetic resonance gyroscope ) 是由 王建龙 高洪宇 王杰英 张俊峰 来琦 于 2019-11-12 设计创作，主要内容包括：本发明涉及一种单激光器的核磁共振陀螺仪,激光器发出的激光经过第一λ/2波片和偏振分束器后实现分束,其中一束经过第一格兰棱镜和λ/4波片转化为圆偏振光直接入射原子气室,用来泵浦极化原子；另一束经过第一反射镜反射改变传播方向后,经过声光调制器移频使得激光远失谐于原子共振线,然后经过第二格兰棱镜,使激光转化为偏振度较高的线偏振光,经过第二反射镜反射后进入原子气室,然后出射光经过第三反射镜反射后,再通过第二λ/2波片和沃拉斯顿棱镜实现分束后分别进入两个探测器实现光电转换,电信号经过信号处理电路后得到陀螺转动信号。本发明采用一个激光器同时产生泵浦光和探测光,节省了一个激光器,简化了结构,便于系统小型化和集成化。(The invention relates to a nuclear magnetic resonance gyroscope of a single laser, wherein laser emitted by the laser realizes beam splitting after passing through a first lambda/2 wave plate and a polarization beam splitter, wherein one beam is converted into circularly polarized light through a first Glan prism and a lambda/4 wave plate and directly enters an atom air chamber for pumping polarized atoms; and the other beam is reflected by the first reflector to change the propagation direction, the frequency of the other beam is shifted by the acousto-optic modulator to enable the laser to be far detuned to an atomic resonance line, then the other beam passes through the second Glan prism to enable the laser to be converted into linearly polarized light with higher polarization degree, the linearly polarized light enters the atomic gas chamber after being reflected by the second reflector, then the emergent light is reflected by the third reflector, beam splitting is realized by the second lambda/2 wave plate and the Volatiton prism, the beam splitting respectively enters the two detectors to realize photoelectric conversion, and the electric signal passes through the signal processing circuit to obtain a gyro rotation signal. The invention adopts one laser to generate the pump light and the probe light simultaneously, thereby saving one laser, simplifying the structure and facilitating the miniaturization and the integration of the system.)

1. A single laser nmr gyroscope, comprising:

the device comprises a laser, a first lambda/2 wave plate, a polarization beam splitter, a first Glan prism, a lambda/4 wave plate, a first reflector, an acousto-optic modulator, a second Glan prism, a driving radio frequency circuit, a second reflector, a magnetic shielding cylinder, a magnetic field control coil, a non-magnetic heating mechanism, an atomic gas chamber, a third reflector, a second lambda/2 wave plate, a Wollaston prism, a photoelectric detector and a signal processing circuit;

the atomic gas chamber is positioned in the center of the magnetic shielding cylinder, and the magnetic heating mechanism, the magnetic field control coil and the magnetic shielding cylinder are arranged in sequence from inside to outside; the second reflector and the third reflector are respectively positioned at the left side and the right side of the innermost layer of the magnetic shielding cylinder and the middle part of the magnetic field control coil, and the laser, the first lambda/2 wave plate, the polarization beam splitter, the first Glan prism, the lambda/4 wave plate, the first reflector, the acousto-optic modulator, the second Glan prism, the second lambda/2 wave plate, the Wollaston prism, the photoelectric detector and the signal processing circuit are all positioned at the outer side of the outermost layer of the magnetic shielding cylinder;

the laser emitted by the laser device realizes beam splitting after passing through the first lambda/2 wave plate and the polarization beam splitter, wherein one beam is converted into circularly polarized light through the first Glan prism and the lambda/4 wave plate and directly enters the atom air chamber for pumping polarized atoms; and the other beam is reflected by the first reflector to change the propagation direction, the frequency of the other beam is shifted by the acousto-optic modulator to enable the laser to be far detuned to an atomic resonance line, then the other beam passes through the second Glan prism to enable the laser to be converted into linearly polarized light with higher polarization degree, the linearly polarized light enters the atomic gas chamber after being reflected by the second reflector, then the emergent light is reflected by the third reflector, beam splitting is realized by the second lambda/2 wave plate and the Volatiton prism, the beam splitting respectively enters the two detectors to realize photoelectric conversion, and the electric signal passes through the signal processing circuit to obtain a gyro rotation signal.

2. The single laser nuclear magnetic resonance gyroscope of claim 1, wherein: and the included angle between the polarization axis of the first Glan prism and the polarization axis of the lambda/4 wave plate (5) is pi/4.

Technical Field

The invention belongs to the technical field of quantum sensing devices, and particularly relates to a nuclear magnetic resonance gyroscope of a single laser.

Background

In recent years, with the rapid development of quantum technology and the need for improving the performance of inertial navigation systems, many atomic gyros have attracted attention. The nuclear magnetic resonance gyroscope is an atomic spin gyroscope with higher maturity, utilizes the invariance sensitive carrier rotation information of precession frequency of atomic spin magnetic moments in a static magnetic field, and has the remarkable advantages of high precision, small volume, large dynamic, low power consumption and the like.

A nuclear magnetic resonance gyroscope uses mainly the spins of inert gas nuclei to perform rotation measurements, as shown in fig. 1. The atomic nuclear spins have randomness under natural conditions and no macroscopic magnetic moment. When an external magnetic field B is applied in the z direction₀When the magnetic moment of the nuclear spin is oriented parallel or antiparallel to the magnetic field direction, i.e. the atoms are distributed at the high and low energy levels of the ground state. In a magnetic field B₀When a circularly polarized pump laser is applied in the same direction, the atoms with low energy level are transited to polarize the atoms, and the magnetic moments of the atoms are wound around a magnetic field B₀Acting as a larmor precession having a precession frequency of

ω＝γB₀(1)

At this time, the magnetic moment of each nuclear spin precesses in phase, and thus the total magnetic moment is zero in the x-y plane. Applying an alternating magnetic field B in the x-direction_AThe frequency is made to be the same as the atom precession frequency. The atoms can absorb magnetic field energy to generate nuclear magnetic resonance, so that the phases of the nuclear magnetic moments are kept consistent, and the rotation frequency of the measured x-y plane nuclear magnetic moment is the same as the precession frequency of the nuclear magnetic moment. A beam of linearly polarized laser is applied in the x direction for detection, and the component of the macroscopic magnetic moment of the atom in the x-y plane can deflect the polarization direction of the linearly polarized light, so that the measurement is realized. The detection laser rotates along with the carrier when the carrier winds around B₀Direction is by omega_rThe nuclear magnetic resonance frequency observed by the probe light during rotation is

ω＝γB₀+ω_r(2)

The measurement of the carrier rotating speed by the nuclear magnetic resonance gyroscope can be realized by the formula.

In recent years, nuclear magnetic resonance gyroscopes have been developed at a rapid pace. Under the fundamentation of DARPA in the united states in 2012, the navigation-grade nuclear magnetic resonance gyroscope engineering prototype with a header volume of 5cm3 and a zero bias stability of 0.01 °/h has been developed by the company norsrop grulman. A prototype with a sensitive volume of 64mm3 and a gauge head volume of 50cm3 is developed by Beijing automated control equipment research institute in 2015, and the zero offset stability of the prototype is superior to 1 degree/h. At present, most of the solutions of the nuclear magnetic resonance gyroscope utilize two lasers to respectively generate linear polarization and circularly polarized light to vertically enter from a gas chamber to respectively realize detection and pumping. This makes the system structure complicated and costly, which is disadvantageous for integration and miniaturization.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides the single-laser nuclear magnetic resonance gyroscope which is simple in system structure and convenient for system miniaturization.

The above object of the present invention is achieved by the following technical solutions:

a single laser nmr gyroscope, comprising:

the device comprises a laser, a first lambda/2 wave plate, a polarization beam splitter, a first Glan prism, a lambda/4 wave plate, a first reflector, an acousto-optic modulator, a second Glan prism, a driving radio frequency circuit, a second reflector, a magnetic shielding cylinder, a magnetic field control coil, a non-magnetic heating mechanism, an atomic gas chamber, a third reflector, a second lambda/2 wave plate, a Wollaston prism, a photoelectric detector and a signal processing circuit;

the atomic gas chamber is positioned in the center of the magnetic shielding cylinder, and the magnetic heating mechanism, the magnetic field control coil and the magnetic shielding cylinder are arranged in sequence from inside to outside; the second reflector and the third reflector are respectively positioned at the left side and the right side of the innermost layer of the magnetic shielding cylinder and the middle part of the magnetic field control coil, and the laser, the first lambda/2 wave plate, the polarization beam splitter, the first Glan prism, the lambda/4 wave plate, the first reflector, the acousto-optic modulator, the second Glan prism, the second lambda/2 wave plate, the Wollaston prism, the photoelectric detector and the signal processing circuit are all positioned at the outer side of the outermost layer of the magnetic shielding cylinder;

the laser emitted by the laser device realizes beam splitting after passing through the first lambda/2 wave plate and the polarization beam splitter, wherein one beam is converted into circularly polarized light through the first Glan prism and the lambda/4 wave plate and directly enters the atom air chamber for pumping polarized atoms; and the other beam is reflected by the first reflector to change the propagation direction, the frequency of the other beam is shifted by the acousto-optic modulator to enable the laser to be far detuned to an atomic resonance line, then the other beam passes through the second Glan prism to enable the laser to be converted into linearly polarized light with higher polarization degree, the linearly polarized light enters the atomic gas chamber after being reflected by the second reflector, then the emergent light is reflected by the third reflector, beam splitting is realized by the second lambda/2 wave plate and the Volatiton prism, the beam splitting respectively enters the two detectors to realize photoelectric conversion, and the electric signal passes through the signal processing circuit to obtain a gyro rotation signal.

And the included angle between the polarization axis of the first Glan prism and the polarization axis of the lambda/4 wave plate is pi/4.

The invention has the advantages and positive effects that:

the invention adopts one laser to generate the pump light and the probe light simultaneously, saves the cost of one laser compared with the nuclear magnetic resonance gyro scheme of two lasers, has simpler structure and is convenient for system miniaturization and integration.

Drawings

FIG. 1 is a schematic diagram of a nuclear magnetic resonance gyroscope.

Fig. 2 is a schematic diagram of an optical path structure of a single-laser nmr gyroscope according to the present invention.

Detailed Description

The present invention will be described in further detail with reference to the following embodiments, which are illustrative only and not limiting, and the scope of the present invention is not limited thereby.

Referring to fig. 1-2, a single-laser nmr gyroscope includes:

the laser comprises a laser 1, a first lambda/2 wave plate 2, a polarization beam splitter 3, a first Glan prism 4, a lambda/4 wave plate 5, a first reflector 6, an acousto-optic modulator 7, a second Glan prism 8, a driving radio frequency circuit 9, a second reflector 10, a magnetic shielding cylinder 11, a magnetic field control coil 12, a non-magnetic heating mechanism 13, an atom gas chamber 14, a third reflector 15, a second lambda/2 wave plate 16, a Wollaston prism 17, a photoelectric detector 18 and a signal processing circuit 19, wherein:

the atomic gas chamber is positioned in the center of the magnetic shielding cylinder, and the magnetic heating mechanism, the magnetic field control coil and the magnetic shielding cylinder are arranged in sequence from inside to outside; the second reflector and the third reflector are respectively positioned at the left side and the right side of the innermost layer of the magnetic shielding cylinder and the middle part of the magnetic field control coil, and the laser, the first lambda/2 wave plate, the polarization beam splitter, the first Glan prism, the lambda/4 wave plate, the first reflector, the acousto-optic modulator, the second Glan prism, the second lambda/2 wave plate, the Wollaston prism, the photoelectric detector and the signal processing circuit are all positioned at the outer side of the outermost layer of the magnetic shielding cylinder.

The laser is tuned to resonate its wavelength with the atomic line. Laser emitted by the laser device is split after passing through the first lambda/2 wave plate and the polarization beam splitter, wherein one laser beam is polarized through the first Glan prism and converted into completely linearly polarized light, the included angle between the lambda/4 wave plate polarization axis and the polarization axis of the first Glan prism is pi/4 by adjusting the lambda/4 wave plate polarization axis, and the laser passing through the lambda/4 wave plate is converted into circularly polarized light with higher polarization degree and is directly incident into the atom air chamber as pump light for pumping polarized atoms. And the other beam is reflected by the first reflecting mirror to change the transmission direction, then generates +/-1-order diffraction light by the acousto-optic modulator, adjusts the driving radio frequency of the acousto-optic modulator according to the atomic spectral line, so that +/-1-order diffraction laser is far detuned to the atomic resonance line, and then the + 1-order diffraction light is polarized by the second Glan prism, so that the emergent light is converted into linearly polarized light with higher polarization degree and enters the atomic gas chamber after being reflected by the second reflecting mirror. Linearly polarized light can be regarded as synthesis of left-handed circularly polarized light and right-handed circularly polarized light, and polarized atoms have different refractive indexes for the left-handed circularly polarized light and the right-handed circularly polarized light, so that phase difference can be generated, and the polarization direction of the synthesized linearly polarized light can rotate. After the emergent linearly polarized light is reflected by the third reflector, the polarized split beams are respectively transmitted into the two detectors through the second lambda/2 wave plate and the Wollaston prism to realize photoelectric conversion, so that the polarized components in the horizontal direction and the vertical direction can be obtained through the light intensity obtained by the two detectors, and further the rotation information of the polarization direction can be obtained. The electric signal is processed by a signal processing circuit to obtain a gyro rotation signal.

The acousto-optic modulator makes laser generate + -1 st order diffraction light, and the-1 st order and the +1 st order diffraction light are respectively red and blue detuned light. An acousto-optic modulator is a physical process that uses the acousto-optic effect to load information into an optical frequency carrier field. The modulation signal acts on the electro-acoustic transducer in the form of electric signal and then is converted into the ultrasonic field changed in the form of electric signal, when the light wave passes through the acousto-optic medium, the light carrier wave is modulated into the intensity modulation wave carrying information due to the acousto-optic effect. Wherein the electro-acoustic transducer is a piezoelectric transducer using some piezoelectric crystal (quartz, LiNbO)₃Etc.) or a piezoelectric semiconductor (Cds, ZnO, etc.), generates mechanical vibration under the action of an external electric field to form ultrasonic waves, and plays a role in converting modulated electric power into acoustic power. A sound absorbing device is placed opposite the ultrasonic source to absorb sound waves that have passed through the medium so as not to interfere with the return of the medium. Acousto-optic interaction is performed in an acousto-optic medium, and when a beam of light passes through a changing sound field, the emergent light has diffraction light of each level which changes along with time due to the interaction of the light and the ultrasonic field. If the first order diffracted light is taken as output, the diaphragm can be used for shielding the diffracted light of other orders. In the experiment, a proper modulation signal frequency is selected according to needs, so that the + 1-level light and the atomic resonance line are subjected to far detuning and serve as detection light.

In this single laser's nuclear magnetic resonance gyroscope laser emergent light divides the back, and a beam of light turns into circular polarization as the pump light, and another beam of light is as the detecting light after the acousto-optic modulator frequency shift, compares in the current technical scheme that utilizes two lasers to produce linear polarization respectively and circular polarization is perpendicular to realize respectively from the air chamber incidence surveying and pumping effect, has saved a laser, and the structure is also simpler, the system miniaturization and the integration of being convenient for.

Although the embodiments of the present invention and the accompanying drawings are disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and therefore the scope of the invention is not limited to the disclosure of the embodiments and the accompanying drawings.