Growth of Thiospinels (Investigation of Crystals For CO2 High Power Laser Windows)

摘要

The report deals with the investigation of single crystals for higher power laser windows. The following crystals were grown and their optical properties studied: KF, RbF, CsF; NaCl, KCl, RbCl; KBr, RbBr, CsBr; CsI; AgBr; CuCl; PbCl2, PbBr2; CdS, In2S3, and CdS.In2S3. The ultraviolet (or visible) and infrared absorption edges were measured. The influence of absorption maxima, temperature and impurities on the absorption edges is discussed. Comparing the absorption at 10.6 micro m with infrared absorption edges, there is an evident relation: for most crystals the absorption at 10.6 micro m decreases with increasing spectral distance from the absorption edges. RbCl has the lowest absorption of all investigated crystals. Deviation from the above relation in some crystals is correlated to crystal defects or surface contamination. The pure polyatomic semi-conductors, CdS, In2S3 and CdS.In2S3 showed two orders of magnitude higher absorption than most ionic crystals and therefore are not suitable for high power laser windows. For better windows a further improvement of crystal purity is necessary. (Author)