共通光路ホログラフィー干渉計

抄録

A simple holographic interferometer for a phase object is presented. The object under test is placed close to a Ronchi grating. The light passing through the grating and the object is spatially divided into many diffraction components on the Fourier transform plane of a lens where a mask with two holes is inserted. The Oth order component passes through one of the two holes which is so small that the extention of the spectrum containing the object information is cut off. The 1st order component passes through the other hole which is large enough to transmit the complete object spectrum. These two waves become the reference wave and object wave for making the hologram and they take almost common path. Therefore, interferogram obtained in this method is stable against the external vibration. Since the carrier of the hologram has the same frequency as that of the grating, a high resolution photographic plate is not necessary.