Michelson Heterodyne Laser Vibrometer Based on Single Acousto-optic Modulation and Polarization Spectroscopy

Abstract

The Michelson heterodyne laser vibrometer based on single acousto-optic modulation and polarization splitting belongs to the field of laser interferometry; the polarization beam splitter PBS is used to split the light to form the reference arm and the measurement arm, and the incident beam on the reference arm is diffracted by the acousto-optic modulator. The frequency-shifted first-order diffracted light is adjusted by the beam deflection element, so that the beam propagation direction is parallel to the incident beam; by adjusting the reference corner cube, the reflected light is located above the AOM, so that the reference light only passes through the AOM once. , adjust the measurement corner cube to make the reference light and the measurement light beams overlap when they pass through the polarization beam splitter PBS again, and interference occurs; the invention uses fewer optical elements to achieve heterodyne laser interferometry, and the adjustment of the optical path is simple, which can effectively solve the current problem. There are problems such as complex optical path adjustment in some technical solutions, and it has significant technical advantages in the field of ultra-precision vibration measurement.

Description

technical field [0001] The invention belongs to the field of laser interferometry, and mainly relates to a Michelson heterodyne laser vibrometer based on single acousto-optic modulation and polarization splitting. Background technique [0002] As an ultra-precision measuring instrument that can trace the vibration value to the laser wavelength, the laser vibrometer is widely used in the fields of dynamic displacement measurement, vibration measurement and monitoring, ultra-precision equipment and system integration, scientific research and experiments. Laser vibrometers based on laser interferometry can be divided into two categories, homodyne and heterodyne, according to the principle. The two have significant differences in working principle, optical path structure and technical characteristics. The homodyne measurement method uses a single-frequency laser as the light source, based on the classic or improved Michelson laser interference principle, and directly measures th...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a Michelson sensor based on single acousto-optic modulation and polarization splitting for the existing Mach-Zehnder heterodyne laser vibrometer technology solutions in terms of optical path structure and principle. The heterodyne laser vibrometer, through the innovation of the optical path structure and principle, is based on the Michelson interferometer, and uses fewer optical components to achieve heterodyne laser interferometry. The adjustment is simple and convenient, which can effectively solve the existing technical solutions. Significant polarization leakage and polarization aliasing, difficult to adjust the optical path

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