Abstract

Tunable ultra-violet solid state lasers are desirable for many applications in medicine, industry, and scientific research, including remote sensing. High absorption and stimulated emission cross sections of the dipole allowed 4f – 5d transitions show promise in cerium as a laser ion in crystals. Several research groups have already reported the observation of stimulated emission of cerium in LiYF₄ [1], LiSrAlF₆ [2], and LiCaAlF₆ [3,4]. However, the color center formation in the crystals due to the excited state absorption of ultra-violet pump light adds difficulty to achieving laser action. [5,6]. We have investigated the spectroscopic properties of cerium such as absorption and emission spectra in five different fluoride crystals, including LiCaAlF₆, LiSrAlF₆, KYF₄, LiYF₄ and GdLiF₄. We have derived the polarized absorption and stimulated emission cross sections from transmission and fluorescence emission measurements for each of the host crystals, except GdLiF₄. We have measured the lifetime of the lowest 5d level moreover investigated the temperature dependence of this lifetime and the color center formation. Our results on absorption and stimulated emission cross sections for LiCaAlF₆ and LiSrAlF₆ are similar to the results already published [7].

© 1995 Optical Society of America