Coherence-length adapted hologram-interferometer.

The design of a diffraction shearing hologram interferometer is analyzed. It is used for temporal coherence measurements of thermal and laser sources. Formulas, geometries, experimental setup, and correction factors for spatial coherence and for the finite dimension of the detector surface are given. Models of holograms, adapted to coherence lengths in the submillimeter, millimeter, and centimeter range are proposed. The inapplicability in the cw gas laser range is stressed. Experimental results are compared with those of a Michelson interferometer and with another holographic technique.