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A cascaded planarized holographic optical sensor consisting of a combination of a leaky beam splitter and a polarization beam splitter is evaluated for possible use in magneto-optic data storage pickup heads. The performance requirements for each element are specified, and two cascaded grating designs are considered. In one design we reconstruct the gratings with the grating vector in the plane of incidence, using a half-wave plate. In the second design we reconstruct the gratings with the grating vector of the polarization beam splitter out of the plane of incidence without using a half-wave plate. The two systems are fabricated with gratings formed in dichromated gelatin emulsions, and they can detect 0.5 degrees rotations in the polarization state of an incident beam by use of a differential detection system.

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 first 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.