Assessment of gadolinium calcium oxoborate (GdCOB) for laser applications

Increasing demand for growing high quality laser crystals puts a question about their most important parameters that one should concentrate on to get a desired product which will exhibit best properties in practical use. And by no means, this is a simple question. Apart of the usual lasing properties associated with a special dopant in the host material itself, one needs to consider another two lasing phenomena, namely second (SHG) and higher harmonic generation, and self-frequency doubling (SFD). Not necessarily all of these three can meet altogether in the same host material to yield in its best appearance in every case. We have made a review of basic properties of gadolinium oxoborate GdCa₄O(BO₃)₃ (GdCOB) crystal and came to the conclusion that, currently, as a host material this is probably the best in all of its lasing applications. Although GdCOB has low thermal conductivity, which requires a suitable cooling, on the other hand it has got small thermo-optic coefficients which govern good operation in SHG and SFD experiments.