Measurement of in-plane displacement by wavelength-modulated heterodyne speckle interferometry

Ju Yi Lee, Ming Pei Lu, Kun Yi Lin, Szu Han Huang

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


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 μm and displacement variation down to the nanometer range. Moreover, the sensitivity can reach up to 0.8°/nm. The performance of the system is discussed.

Original languageEnglish
Pages (from-to)1095-1100
Number of pages6
JournalApplied Optics
Issue number8
StatePublished - 10 Mar 2012


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