Bandpass filtering in barium titanate.

Real-time spatial filteirng is performed in BaTiO(3) using two different holographic geometries. In both geometries white light images of moderate intensity are used to filter selected portions of Fourier transform holograms written in the crystal. The result is a suppression of certain spatial frequencies in the reconstructed images. The geometries consist of a typical four-wave mixing arrangement and a new self-reading setup. In both geometries erase images are supplied by a commercial projection system. These arrangements permit one to generate and position spatial filters electronically, thereby avoiding the often difficult process of physical preparation and alignment of conventional spatial filters. Other image processing applications of the self-reading configuration are also discussed.