Infrared polycrystalline waveguides made of silver halides

Single crystals of AgCl and AgBr and of their solid solution KRS-13 were grown. The lowest absorption was exhibited by the solid solution: it amounted to 6×10^–5cm^–1 at 10.6μ and 1.4×10^–4cm^–1 at 5–6μ. An investigation of the edges of many-phonon absorption yielded estimates of the minimum intrinsic optical losses, which were 10^–1–10^–2 dB/km at wavelengths in the range 5–10μ. Extrusion was used in the preparation of polycrystalline fiber waveguides from AgCl, AgBr, and KRS-13. The optical losses at 10.6μ in the waveguides made of AgCl (0.5 dB/m) and in KRS-13 (1.3 kB/m) were governed by the absorption, whereas in the AgBr waveguide (3.5 dB/m) they were governed by the scattering. A polycrystalline KRS-13 waveguide was prepared for the first time and it exhibited a high breaking strength (~150 MPa and a low minimum radius of elastic bending (~5 cm).