VOLUME HOLOGRAPHIC PHASE-RETARDATION ELEMENTS

The form birefringence of subwavelength period gratings can be applied to realize phase-retardation elements. Previous researchers used high -frequency surface relief structures or sinusoidal gratings formed in photoresist to fabricate phase-retardation elements. We present the pe rformance of a volume holographic quarter-wave phase-retardation eleme nt formed in a dichromated gelatin emulsion for operation at 632.8 nm. To our knowledge this is the first demonstration of a retardation ele ment exhibiting this magnitude of phase delay in a volume material. Th e phase properties of volume gratings are investigated by both effecti ve medium theory and rigorous coupled-wave analysis. (C) 1995 Optical Society of America