Self-focusing and optical damage in Cr:LiSAF and Cr:LiCAF

Abstract

The Cr-doped Colquiriites, Cr:LiSAF, and Cr:LiCAF, are new solid-state laser materials with high gain cross-sections, very large gain bandwidths, and relatively long fluorescence lifetimes (approximately 100 microsecond(s) ) making them amenable to flashlamp pumping. These laser materials are capable of providing tunable high power laser radiation in the near IR and are very suitable for ultrashort pulse generation and amplification. For these high power laser applications, however, a knowledge of the optical damage thresholds and mechanisms in these materials is essential. We present results of measurements of bulk damage thresholds, of basic material properties, and of the nonlinear refractive indices of these materials. We have also observed optical damage due to self-focusing in a femtosecond chirped pulse Cr:LiSAF regenerative amplifier. We discuss these observations and give an estimate of the critical power of self-focusing for these materials.