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...

Examples

Embodiment Construction

[0022] The specific implementation manner of the present invention will be described in detail below with reference to the accompanying drawings, and examples will be given.

[0023] A Michelson heterodyne laser vibrometer based on single acousto-optic modulation and polarization splitting, consisting of a laser 1, a half-wave plate 14, a polarization beam splitter 2, a quarter-wave plate 3, and a measuring corner cube prism 4 , an acousto-optic modulator 5, a beam deflection element 6, a reference corner cube 7, a polarizer 15, and a high-speed photodetector 8. The laser 1 emits linearly polarized light, and the polarization is adjusted by a half-wave plate 14 direction, and then split the light through the polarizing beam splitter 2, the reflected light forms the first beam 9 as the measuring light, and the transmitted light forms the second beam 10 as the reference light; the first beam 9 becomes circularly polarized after passing through the quarter-wave plate 3 The light,...

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...

Examples

Embodiment Construction

[0022] The specific implementation manner of the present invention will be described in detail below with reference to the accompanying drawings, and examples will be given.

[0023] A Michelson heterodyne laser vibrometer based on single acousto-optic modulation and polarization splitting, consisting of a laser 1, a half-wave plate 14, a polarization beam splitter 2, a quarter-wave plate 3, and a measuring corner cube prism 4 , an acousto-optic modulator 5, a beam deflection element 6, a reference corner cube 7, a polarizer 15, and a high-speed photodetector 8. The laser 1 emits linearly polarized light, and the polarization is adjusted by a half-wave plate 14 direction, and then split the light through the polarizing beam splitter 2, the reflected light forms the first beam 9 as the measuring light, and the transmitted light forms the second beam 10 as the reference light; the first beam 9 becomes circularly polarized after passing through the quarter-wave plate 3 The light,...

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