Polarization- and aliasing-resistance Michelson heterodyne laser vibration measurer based on double acousto-optic modulation and non-polarizing light splitting

Abstract

A polarization- and aliasing-resistance Michelson heterodyne laser vibration measurer based on double acousto-optic modulation and non-polarizing light splitting belongs to the field of laser interference measurement. A non-polarizing beam splitter (NBS) is adopted to perform light splitting and then form a reference arm and a measuring arm, incident light beams on the reference arm and the measuring arm generate diffraction via acousto-optic modulators, and frequency-shifted first-stage diffraction light are adjusted through light beam folding elements, so light beam propagation directions are parallel to the incident light beams; reflected light is located over acousto-optic modulators through adjustments of cube-corner prisms, so measuring light and reference light respectively pass through the acousto-optic modulators for one time; and the reference cube-corner prism and the measuring cube-corner prism are adjusted, so light beam superposition occurs when the reference light and the measuring light pass through the non-polarizing beam splitter (NBS) again, and an interference is generated. Heterodyne laser measuring is achieved through adoption of less optical elements, optical path adjustments are simple, problems of polarization leakage, polarization aliasing, complex optical path adjustments and the like which exist in an existing technical scheme can be effectively solved, and the laser vibration measurer has an obvious technical advantage in the ultra-precision vibration measurement field.

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 dual 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 princip...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a dual 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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