High-efficiency, wide-bandwidth optical fanout elements in dichromated gelatin.

We have combined the flexibility of computer-generated binary holograms with the high optical quality of dichromated gelatin holography to fabricate a range of efficient, wide-bandwidth, and compact space-invariant fanout elements. Our approach is based on a certain novel coherent spatial filtering technique, termed the inverse central dark ground method, which permits the use of a binary-amplitude hologram corresponding to the desired binaryphase profile in the object arm of the interferometric recording setup.