Loss and gain measurements in the tunable UV solid state laser systems Ce:YLiF/sub 4/ and Ce:LiLuF/sub 4/

Summary form only given. Continuous laser wavelength tunability of Ce: LiLuF/sub 4/ (LLF) between about 304 and 333 nm was recently obtained by pumping the crystal either with the frequency-doubled radiation of a copper-vapor or the UV radiation of a Ce:LiSAF laser. These laser results, however, raised a number of questions concerning the polarization flipping observed around 327 nm and the poor laser performance observed under /spl sigma/ polarization conditions. Time-resolved pump-probe measurements were thus performed to clarify these questions and to attempt to elucidate the role of well known detrimental effects such as excited-state absorption (ESA) into the conduction band of the crystals and/or color center formation. Our data show unambiguously that optical losses in Ce:LLF and Ce:YLF are predominantly due to absorption of laser radiation by color centers which have been produced by UV laser pumping.