[摘要]：The use of wavelength-modulated light incorporated into an optical-path-difference speckle interferometer is demonstrated as a heterodyne technique for measuring the in-plane displacement of a rough object. The in-plane displacement can be determined from the measured phase variation of the heterodyne speckle signal. We also improved the optical configuration to create a high-contrast interference pattern. Experimental results reveal that the proposed method can detect displacement up to a long range of 220 mu m and displacement variation down to the nanometer range. Moreover, the sensitivity can reach up to 0.8 degrees/nm. The performance of the system is discussed. (C) 2012 Optical Society of America
