A New Self-mixing Interferometer for Micro-displacement Reconstruction

摘要

A new self-mixing interferometer based on sinusoidal phase-modulating technique for micro-displacement reconstruction is presented in this paper. Phase modulation of the laser beam is obtained by an electro-optic modulator (EOM) in the external cavity. Fourier analysis method is proposed to demodulate the phase. The optimum values of the modulation frequency and modulation depth are discussed. Theoretical analysis and simulation results are given. Experimentally, the micro-movement of a high precision commercial PZT has been reconstructed, which can obtain a displacement measurement accuracy of a few nanometers.