Micro-vibration measurement using self-mixing interferometer based on temporal carrier phase shifting technique

Abstract

A new self-mixing interferometer (SMI) based on temporal carrier phase shifting technique is presented. Self-mixing interference occurs in the laser cavity by reflecting the light from a mirror-like target in front of the laser. Triangular phase modulation of the beam is obtained by an electrooptic modulator (EOM) in the external cavity. The phase of SMI signal coming from the photodetector is extracted by the phase shift demodulation algorithm based on sampling technique. Theoretical analysis and simulation calculations are presented and some errors of this method are discussed. The interferometer is applied to measure the Micro-vibration of a high-precision commercial PZT with an accuracy of <10nm.