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 performance of a volume holographic quarter-wave phase-retardation element formed in a dichromated gelatin emulsion for operation at 632.8 nm. To our knowledge this is the f irst demonstration of a retardation element exhibiting this magnitude of phase delay in a volume material. The phase properties of volume gratings are investigated by both effective medium theory and rigorous coupled-wave analysis.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics