Two-wavelength holographic interferometry for transparent media using a diffraction grating

A new technique of two-wavelength nondiffuse holographic interferometry is demonstrated that is capable of producing interferograms of transparent media with high or low sensitivity. Incorporating an arrangement similar to Bryngdahl's longitudinally reversed shearing interferometer, the technique works by superposing the reconstructed true and/or conjugate images of two transmission image holograms of the test medium recorded at different wavelengths. Extensions of the technique allow one to record interferograms sensitive only to the optical dispersion of the test medium and to generate light beams with phase distributions equal to the sum or difference of the phases of the original object beams.