Abstract

For diffraction gratings having a spatial frequency above a certain threshold, all diffracted orders but the zeroth orders are evanescent. The condition for zeroth order diffraction is simple if the incident beam is normal to the hologram surface. Such gratings exhibit form birefringence, and waveplates of arbitrary phase retardation can be made by properly adjusting the birefringence and grating thickness. The effects of grating period, permittivity modulation profile, and other parameters are theoretically investigated using rigorous coupled wave theory to determine the conditions for maximum phase retardation. Experimental results for zeroth order gratings recorded in dichromated gelatin are presented, and deviations from theory are explored. Finally, a comparison is made to the results obtained by other researchers using surface relief gratings.

© 1993 Optical Society of America