Holography in a Random Spatially Inhomogeneous Medium

摘要

The Huygens-Fresnel principle, extended to a medium that exhibits a random spatial variation in the index of refraction, is used to calculate the resulting fringe patterns in the Fresnel-Fraunhofer and point-reference Fourier transform methods of holography. The resolution limits pertaining to these two methods are derived. In the Fresnel-Fraunhofer method, the effect of the medium is a lateral reduction in the size of the hologram, which leads to a corresponding loss of resolution. In the point-reference Fourier-transform method, on the other hand, the medium does not limit the lateral extent of the hologram but gives a uniform reduction in contrast to the resulting fringe pattern. Thus, in the latter method, resolution is not degraded, but the medium does limit the size of objects that can form holograms. Numerical results pertaining to underwater holography are given. (Author)