Based on the sinusoidal phase-modulation laser self-mixing interference technique,the precision measure-ment of the small vibration on the rough surface is realized,such as speaker surface or white paper.The 532nm solid-state laser is selected as the laser light source.And the sinusoidal phase-modulation of the laser is achieved based on the e-lectro-optical modulator,with a corresponding modulation frequency of 251kHz.By using the mixer/filter circuits,the high signal-to-noise ratio sinusoidal and cosine function laser power oscillation signals caused by displacement change are extracted from the self-mixing interference optical fringes modulated by sinusoidal phase-modulation,further obtaining the phase change of the laser caused by displacement change.Therefore,the vibration and displacement of external tar-gets can be efficiently calculated from the phase change of the laser.By comparing the measurement results with a preci-sion displacement platform with an accuracy of 50nm,the two instruments showed good agreement,and the performance of the laser self-mixing interferometer was experimentally verified.The new technology can provide reliable technical sup-port for high-precision low-frequency micro-vibration and micro-displacement measurement.
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