Abstract

White light images are used to perform real-time spatial filtering in BaTiO₃ in two different geometries. White light images act as spatial filters by erasing certain frequency components of photorefractive Fourier transform holograms. As a result, these frequency components are suppressed in the reconstructed holographic images. In both geometries filters are illuminated using a commercial slide projector and imaged into the crystal. The two geometries differ in the method employed to read the hologram. In one of the arrangements, a separate read beam is needed in addition to the object Fourier transform and plane-wave reference beam. The other geometry is self-reading employing only the object beam and a strong self-pumping reference. Although the self-reading system is virtually self-aligning, its filtering characteristics differ from the four-wave mixing setup. With only minimal changes these arrangements permit electronic generation and positioning of spatial filters.

© 1988 Optical Society of America