High-resolution photorefractive incoherent-to-coherent optical converter

We demonstrate a novel photorefractive incoherent-to-coherent optical conve rter in which there is a similar to 45 degrees angle between the propagatio n direction of the incoherent image and the grating vector. Thus the number of the grating periods in one pixel is large even for a very high resoluti on. When the output image has the same direction with the incoherent incide nt beam, the resolution does not depend on the interaction length between t he incoherent beam and the grating. A resolution as high as 283 Line pairs/ mm, which is the resolution of out projection system, is obtained for a one -dimensional resolution target. Two-dimensional incoherent-to-coherent conv ersion is also demonstrated. (C) 2000 Elsevier Science B.V. All rights rese rved.