CROSSED PHASE GRATINGS WITH DIFFRACTIVE OPTICAL-ELEMENTS

Orienting two identical or complementary diffractive gratings with a s mall angle between the grating grooves allows a new crossed-grating de vice to be constructed. This device has an effective profile that vari es locally. For understanding the effects of this variation and the di ffraction efficiency of the gratings, the local profiles were correlat ed with the moire period of the crossed-grating system by use of vario us techniques. Asymmetric intensity behavior in the first order of the crossed gratings was seen. Effectively, the diffraction efficiency of the crossed gratings yielded a response equivalent to that of a grati ng with Variable blaze that could be useful in optical computing as a passive optical switching device. One of several models is described t hat creates greater asymmetric behavior. (C) 1998 Optical Society of A merica.