Optical losses of AgClBr crystals and fibers in the middle infrared

The porosity and the optical properties were measured in single crystals of AgClBr, and in rods and fibers of different diameters extruded from these crystals. It was found that the porosity, the absorption and the scattering at 10.6 μm increased, when the sample diameter decreased. We suggest that scattering in the samples is mainly due to the pores and we used infrared spectral analysis and Mie theory to calculate the distribution of these pores. We found that the average radius of the pores was 0.4–0.6 μm and the number of scatterers per unit volume was 8 × 109–2.5 × 1011 cm−3. Both increased when the rod diameter decreased. The increase in absorption was consistent with a theoretical model ascribing the absorption to cation vacancies localized at charged dislocations.

► Rods of different diameter and a fiber were extruded from single crystal of AgClBr.
► Porosity, absorption and scattering at 10.6 μm increased when rod diameter decreases.
► Porosity is suggested as main cause for the scattering.