Anti-polarization-aliasing Michelson heterodyne laser vibration measuring instrument based on single acousto-optic modulation and non-polarization beamsplitting

Abstract

The invention provides an anti-polarization-aliasing Michelson heterodyne laser vibration measuring instrument based on single acousto-optic modulation and non-polarization beamsplitting, and belongs to the field of laser interferometry. A non-polarization beamsplitter NBS is used to split beams to form a reference arm and a measuring arm. Through an acoustic optical modulator, diffraction occurs to the incident beam on the reference arm, frequency-shift first-order diffraction light is adjusted through a light beam reflex component, so propagation direction of the light beam is parallel to the direction of the incident beam. Through adjusting a reference cube-corner prism, reflected light is above the acoustic optical modulator, so that the reference light just passes through the acoustic optical modulator for one time. A measuring cube-corner prism is adjusted, so that when the reference light and the measuring light pass through the non-polarization beamsplitter NBS again, light beams are overlapped, and interference occurs. The instrument uses relatively few optical elements to realize heterodyne laser interference measurement, optical path adjustment is simple, and the instrument effectively solves problems in existing technical schemes of polarization leakage and polarization aliasing, and complex optical path adjustment. The instrument has substantial 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 an anti-polarization aliasing Michelson heterodyne laser vibrometer based on single acousto-optic modulation and depolarization 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 princ...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a single-acousto-optic modulation and depolarization splitting anti- The polarization mixing Michelson 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, and can effectively solve the existing problems. In the technical solution, the optical path has significant polarization leakage and polarization aliasing, and it is difficult to adjust the optical path

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