Abstract

The extension of holographic techniques from the visible to the far infrared is important. Potentially, holographic diffractive elements have a large range of uses in this waveband. Examples include mirrors, lenses, filters, and beam combiners. All these elements would have similar advantages to those enjoyed by their visible diffractive analogs. The metal photodissolution effect in chalcogenide glasses shows promise as one of the few techniques for producing low-loss holographic materials for use from 0.6 to beyond 16 μm. To date, the work has concentrated on the photodissolution of silver into arsenic sulfide glasses. Both bulk and surface relief gratings can be fabricated simply using blue or UV light, either by holographic or mask exposure. The results of material characterization studies show that phase gratings with high modulation and low absorption can be produced. A coupled wave analysis using these material parameters has indicated the likely performance achievable and has shown the relative merits of the bulk and surface relief structures. Diffraction efficiencies of over 90% are possible. Both bulk and surface relief gratings have been fabricated, and measurements from them are presented and compared to the theory. The limitations of the medium are discussed, and possible solutions are considered.

© 1988 Optical Society of America