CN112833871A

CN112833871A - Integrated laser power stabilizing system applied to nuclear magnetic resonance gyroscope

Info

Publication number: CN112833871A
Application number: CN202011618252.2A
Authority: CN
Inventors: 李佳佳; 江奇渊; 汪之国; 张燚; 杨开勇; 罗晖
Original assignee: National University of Defense Technology
Current assignee: National University of Defense Technology
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2021-05-25
Anticipated expiration: 2040-12-30
Also published as: CN112833871B

Abstract

The invention provides an integrated laser power stabilizing system applied to a nuclear magnetic resonance gyroscope. The integrated laser power stabilizing system applied to the nuclear magnetic resonance gyroscope comprises a laser, a lambda/2 wave plate, a first linear polarizer, a liquid crystal phase retarder, a lambda/4 wave plate, a second linear polarizer, a beam splitter, a photoelectric detector and a nuclear magnetic resonance gyroscope system; linearly polarized light emitted by the laser sequentially passes through the lambda/2 wave plate, the first linear polarizing plate, the liquid crystal phase retarder, the lambda/4 wave plate, the second linear polarizing plate and the beam splitter, and the beam splitter finally divides the linearly polarized light emitted by the laser into two beams which are respectively received by the photoelectric detector and the nuclear magnetic resonance gyro system. The integrated laser power stabilizing system applied to the nuclear magnetic resonance gyroscope has the advantages of compact structure, convenience in debugging, high power stabilizing precision, weak magnetism and easiness in integration.

Description

Integrated laser power stabilizing system applied to nuclear magnetic resonance gyroscope

Technical Field

The invention relates to the technical field of laser, in particular to an integratable laser power stabilizing system applied to a nuclear magnetic resonance gyroscope.

Background

The nuclear magnetic resonance gyroscope is a novel gyroscope based on a quantum principle, has the advantages of insensitivity to acceleration, strong anti-interference capability, no moving parts and the like, is expected to achieve the precision of an optical gyroscope with the same volume and cost as those of a micro-electromechanical gyroscope, and is widely concerned at home and abroad. In the process of miniaturization and improvement of precision thereof, high precision, miniaturization and non-magnetism of the laser power stabilization module are one of the main research directions thereof.

The current power stabilization scheme with higher precision mainly comprises acousto-optic modulation and electro-optic modulation, the main body of the acousto-optic modulation is an acousto-optic modulator, and the zero-order light and the first-order light have smaller difference angle and are limited by the volume of the acousto-optic modulator, so that the acousto-optic modulator is difficult to meet the requirement of volume limitation in the miniaturization process of a nuclear magnetic resonance gyroscope; the traditional electro-optical modulation scheme introduces new interference magnetic fields and interference signals, and is not suitable for miniaturization of the nuclear magnetic resonance gyroscope. Therefore, a laser power stabilization system with high integration level, small magnetic field interference and high precision is urgently needed to solve the power stabilization problem in the miniaturization process of the nuclear magnetic resonance gyroscope.

Therefore, there is a need to provide a new and integratable laser power stabilization system for an nmr gyroscope to solve the above problems.

Disclosure of Invention

The invention solves the technical problem of providing an integratable laser power stabilization system which has compact structure, convenient debugging, high power stabilization precision, weak magnetism and easy integration and is applied to a nuclear magnetic resonance gyroscope.

In order to solve the above technical problem, the present invention provides an integrated laser power stabilization system for a nuclear magnetic resonance gyroscope, comprising: the device comprises a laser, a lambda/2 wave plate, a first linear polarizer, a liquid crystal phase retarder, a lambda/4 wave plate, a second linear polarizer, a beam splitter, a photoelectric detector and a nuclear magnetic resonance gyro system; linearly polarized light emitted by the laser sequentially passes through the lambda/2 wave plate, the first linear polarizing plate, the liquid crystal phase retarder, the lambda/4 wave plate, the second linear polarizing plate and the beam splitter, and the beam splitter finally divides the linearly polarized light emitted by the laser into two beams which are respectively received by the photoelectric detector and the nuclear magnetic resonance gyro system.

Firstly, aiming at the original light emission of a laser, obtaining linearly polarized light with adjustable power and horizontal polarization direction by adjusting a lambda/2 wave plate and a linear polarizer behind the light emission;

secondly, the linear adjustability of the polarization direction of the original horizontally polarized linear light is realized within a certain range by the combination of liquid crystal phase delay and a lambda/4 wave plate and by the change of liquid crystal control voltage;

then, linearly polarized light with adjustable power and high extinction ratio is obtained by adding a linearly polarizing plate in the vertical direction;

finally, real-time feedback control and stable output of laser power are realized through the beam splitter, the photoelectric detector, the control program and the feedback circuit

Compared with the related art, the integrated laser power stabilizing system applied to the nuclear magnetic resonance gyroscope has the following beneficial effects:

1. the light path system has compact structure, convenient assembly and experimental debugging, easy integration, higher power stabilizing effect and contribution to the design of high-precision integration of the nuclear magnetic resonance gyroscope;

2. the magnetic field generated by the light path system is weaker, and the light path system can be arranged in a nuclear magnetic resonance gyro system without changing the magnetic field environment in the system;

3. the method of adding the lambda/4 wave plate enlarges the linear response area of the system, reduces the requirement of the system on the resolution ratio of the control voltage and improves the control precision of the feedback adjustment of the system.

Drawings

FIG. 1 is an optical diagram of an integrated laser power stabilization system of a nuclear magnetic resonance gyroscope.

FIG. 2 is a plot of photodetector response voltage versus liquid crystal phase retarder control voltage.

Reference numbers in the figures: 1. the device comprises a laser, a 2 lambda/2 wave plate, a 3 first linear polarizer, a 4 liquid crystal phase retarder, a 5 lambda/4 wave plate, a 6 second linear polarizer, a 7 beam splitter, a 8 photoelectric detector, a 9 nuclear magnetic resonance gyro system.

Detailed Description

The invention is further described with reference to the following figures and embodiments.

Please refer to fig. 1 and fig. 2, wherein, fig. 1 is a diagram of an optical path of an integrated laser power stabilization system of an nmr gyroscope. FIG. 2 is a plot of photodetector response voltage versus liquid crystal phase retarder control voltage. The system for stabilizing the integratable laser power applied to the nuclear magnetic resonance gyroscope comprises: the device comprises a laser 1, a lambda/2 wave plate 2, a first linear polarizer 3, a liquid crystal phase retarder 4, a lambda/4 wave plate 5, a second linear polarizer 6, a beam splitter 7, a photoelectric detector 8 and a nuclear magnetic resonance gyro system 9; linearly polarized light emitted by the laser 1 sequentially passes through the lambda/2 wave plate 2, the first linear polarizer 3, the liquid crystal phase retarder 4, the lambda/4 wave plate 5, the second linear polarizer 6 and the beam splitter 7, and the beam splitter 7 finally divides the linearly polarized light emitted by the laser 1 into two beams which are respectively received by the photoelectric detector 8 and the nuclear magnetic resonance gyro system 9.

The specific optical path flow is as follows: linearly polarized light emitted by the laser 1 passes through the lambda/2 wave plate 2 and the first linear polarizer 3, wherein the lambda/2 wave plate 2 and the first linear polarizer 3 have the functions of enabling the polarization direction of subsequent laser to be horizontal by adjusting the optical axis of the first linear polarizer 3, and enabling the optical power of the first linear polarizer 3 to meet the system requirement by adjusting the optical axis of the lambda/2 wave plate 2; after the light after the first linear polarizer 3 passes through the liquid crystal phase retarder 4, the lambda/4 wave plate 5 and the second linear polarizer 6 in sequence, is divided into two beams by a beam splitter 7, is respectively received by a photoelectric detector 8 and a nuclear magnetic resonance gyro system 9, wherein the fast axis of the liquid crystal phase retarder 4 is 45 degrees with the horizontal direction, the fast axis of the lambda/4 wave plate 5 is coincided with the fast axis of the second linear polaroid 6, and are all vertical to the first linear polarizer 3, the linearly polarized light after passing through the liquid crystal phase retarder 4 is changed into elliptical light, and the elliptical light is adjusted by a lambda/4 wave plate 5, the elliptical light is converted back to linearly polarized light, and by changing the voltage of the liquid crystal phase retarder 4, the optical power after the second linearly polarizing plate 6 can be changed, through feedback control of the photoelectric detector 8, stable control of the laser power behind the second linearly polarizing plate 6 is finally achieved, and the laser received by the nuclear magnetic resonance gyro system 9 is linearly polarized light with stable power.

By changing the control voltage of the liquid crystal phase retarder 4, a relation curve between the photoelectric detector 4 and the control voltage shown in fig. 2 can be obtained, and it can be seen that when the control voltage is between 2 and 5V, the test voltage changes approximately linearly, by writing a PID control program in a LabVIEW program and limiting the control voltage between 2 and 5V, the linear control of the laser power can be realized, and the accuracy of feedback regulation control is improved.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. An integratable laser power stabilization system for a nuclear magnetic resonance gyroscope, comprising: the device comprises a laser, a lambda/2 wave plate, a first linear polarizer, a liquid crystal phase retarder, a lambda/4 wave plate, a second linear polarizer, a beam splitter, a photoelectric detector and a nuclear magnetic resonance gyro system; linearly polarized light emitted by the laser sequentially passes through the lambda/2 wave plate, the first linear polarizing plate, the liquid crystal phase retarder, the lambda/4 wave plate, the second linear polarizing plate and the beam splitter, and the beam splitter finally divides the linearly polarized light emitted by the laser into two beams which are respectively received by the photoelectric detector and the nuclear magnetic resonance gyro system.

2. The system of claim 1, wherein the fast axis of the lc retarder is at 45 ° to horizontal.

3. The system of claim 1, wherein the λ/4 plate and the second linear polarizer have their fast axes coincident and are perpendicular to the first linear polarizer.

4. The integratable laser power stabilization system applied to a nuclear magnetic resonance gyroscope of claim 1, wherein linearly polarized light after passing through the liquid crystal phase retarder is transformed into elliptical light, and the elliptical light is transformed back to linearly polarized light through the adjustment of the λ/4 wave plate.

5. The system of claim 1, wherein the voltage variation of the lc phase retarder can change the power of the laser beam after the second linear polarizer, and the feedback control of the photodetector finally realizes the stable control of the power of the laser beam after the second linear polarizer, so that the laser beam received by the nmr gyro system is linearly polarized with stable power.