A Multi-Channel Optical Rotary Joint on the Basis of Off-Axis Holographic Fresnel Lenses

We performed both theoretical and experimental investigations of the possibility for development of radically new types of small-size multi-channel optical rotary joints (ORJs) on the basis of holographic optics to transmit large arrays of broad-band digital signals from rotary objects to stationary ones through the fiber optic communication channels. To make multi-channel ORJs on the basis of off-axis Fresnel lenses, we developed an original optical recording arrangement of ring Fresnel lenses that combines the advantages of axis Fresnel lens and holographic recording. A manufacturing technology for Fresnel lenses on the basis of inorganic chalcogenide photoresist with maximal diffraction efficiency was developed and optimized. Wc fabricated a three-channel ORJ model with the following characteristics: amplitude modulation percentage for a signal in the ORJ optical channel - no more than 7%; crosstalk signal between the optical channels - no more than 10^-5 ; lens diffraction efficiency - 20%