Polycrystalline waveguides with 0.35 dB/m losses at the 10.6 μ wavelength

Polycrystalline waveguides with diameters of 500 μ were extruded from KRS-5 and KRS-6 crystals. A reduction in the average grain size to 3 μ made it possible to ensure that the minimum bending radius was 1 cm. The lowest optical losses in a waveguide made of a KRS-5 crystal were 0.35 dB/m at 10.6μ and they were mainly due to absorption. A waveguide 1-m long transmitted radiation from a cw CO₂ laser of up to 10 W power.