Quadrature phase detection based on phase shift of self-mixing interferometer for real-time displacement measurement

Abstract

A real-time displacement reconstruction technique based on a phase retardation method is proposed. By introducing a waveplate and a polarization beam splitter into the external cavity, two self-mixing signals with a phase shift of π∕2 can be obtained. Then the displacement of the external object can be reconstructed by a quadrature demodulation algorithm, which significantly simplifies the data processing and meets the requirements of real-time displacement reconstruction techniques. The results show that the absolute errors of the reconstructed displacements are less than 75 nm.