These transmissive devices possess a continuous periodic birefringence profile that renders several compelling properties. These properties, which have been experimentally realized, include greater than 98% diffraction efficiency into a single order, high polarization sensitivity, and very low scattering. Light may be controlled between the first diffraction orders by the modifying the circular polarization handedness of the incident light. Additionally, these transmissive devices can be stacked with handedness switches in between (liquid crystal variable retarders, for example) to achieve several electrically-selectable steer angles.
These devices can be combined with our fine angle beam steering LCoS devices to create a continuously-tunable, large angle beam steering system. BNS has constructed systems with a field-of-regard of over 100° in both X and Y dimensions. The graphics below show the composition and one application of such a system. (click for a larger view)