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26 December 1984 Development Of Calcium Lanthanum Sulfide As An 8-12μm Transmitting Ceramic
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Calcium lanthanum sulfide (nominally CaLa2S4) has been under development for almost 4 years as an 8-12 μm transmitting ceramic. During that time, by concentrating the effort on optimizing the optical properties of this material, the absorption coefficient at 10.6 um has been decreased from 40 cm-1 to 0.6 cm-1. Most of the present absorption is thought to be extrinsic. Studies this year have dealt with a number of areas. One of these studies was an attempt to determine the cause of the remaining extrinsic absorption. During the course of this investigation, the presence of additional phases, including calcium sulfide (CaS), has been noted. The presence of CaS is somewhat surprising as all material investigated was 12-30 mole percent calcium deficient. Point defects and "trace" impurities have also been observed. These have been characterized using electron paramagnetic resonance and excitation/emission spectroscopies. Some of the defects and impurities have been identified and their location in either calcium lanthanum sulfide or second phase CaS determined. The possible effects of these defects and impurities on the observed infrared absorption of calcium lanthanum sulfide ceramics will be discussed.
© (1984) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Josephine Covino, Daniel C. Harris, Marian E. Hills, Richard T. Loda, and Robert W. Schwartz "Development Of Calcium Lanthanum Sulfide As An 8-12μm Transmitting Ceramic", Proc. SPIE 0505, Advances in Optical Materials, (26 December 1984);

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