DISPLACEMENT MEASUREMENTS FROM COHERENCE-INDUCED SPECTRAL CHANGES IN A MACH-ZEHNDER INTERFEROMETER

The spectral changes arising due to interference between two partially correlated beams are investigated experimentally in a Mach-Zehnder in terferometer. Two different schemes are used to produce two partially correlated beams. Experimental results obtained from these schemes are compared with the theory. It is shown that the spectral changes in th e form of modulations in the superposed spectrum are dependent on the optical path difference of the two beams in the interferometer and can be utilized for determining linear displacements of a few microns.