Optical Properties Of Silver Halide Infrared Transmitting Fibers

Silver halide crystals of composition AgC10.95Br.0.05 were extruded to form infrared transmitting fibers of 0.9 mm diameter and 1.5 meters in length. Microscopic examination reveals an initial fine grain structure with a grain size of the order of 1 pm. Thermal treatment at 200°C following extrusion results in rapid grain growth. Infrared spectral transmission measurements of the fibers show absorption features at 3-3.2 μm, 6.1 μm and 12-13 μm attributed to water and bands at 6.8 and 7.1 pm attributed to COI molecules. These features are superimposed on a scatter loss which has a λ-2 dependence. Transmission measurements at 10.6 μm with a CO2 laser show a linear dependence of power output on power input for levels from 1 to 20 watts incident on the fiber face. For a variety of power input geometries, the power output distribution was independent of the input conditions.