B.S.T.J. Brief: Holographic Image Projection Through Inhomogeneous Media

This brief reports on an experimental test of a hologram technique that is capable of projecting undistorted images through inhomogeneous media. Coherent laser light and the hologram order that produces a conjugate image are used. The technique may be of interest in controlling wave transmission through inhomogeneous media for communication purposes, and it allows the scrambling or encrypting of texts, drawings, and similar messages for private communication. In common holography there are two coherent waves incident upon the hologram or recording plate.1 These are a signal wave S, originating from an object of interest, and a reference or background wave R. A recording is made of the intensity pattern / = R.R* + S.S* + R*S + R.S* (1)