ULTRAVIOLET-LASER EMISSION PROPERTIES OF CE3-DOPED LISRALF6 AND LICAALF6()

The UV laser properties of trivalent cerium-doped LiSrAlF6 (Ce:LiSAF) and LiCaAlF6 (Ce:LiCAF) are reported. The polarized absorption, emissi on, and excited-state absorption cross sections for both Ce:LiSAF and Ce:LiCAF were determined for the 266-nm pump and 290-nm laser emission wavelengths. The single-exponential emission lifetime was measured to be 28 +/- 2 and 25 +/- 2 ns for Ce:LiSAF and Ce:LiCAF, respectively. The gain was found to be highest when the probe was polarized parallel to the optical axis of the crystal, owing to the anisotropic nature o f the excited-state absorption. The excited-state absorption was ascri bed to a transition from the 5d orbital of Ce3+ to the conduction band of the host. Laser slope efficiencies as high as 29% and 21%, respect ively, were measured for Ce:LiSAF and Ce:LiCAF when the 266-nm pulsed pump beam was polarized parallel to the optical or the c axis. These a re the highest laser slope efficiencies yet observed to our knowledge for any known solid-state UV laser material. When the pump beam was po larized perpendicular to the optical axis of the crystals, the gain an d the laser efficiencies dropped by as much as an order of magnitude. The magnitude of pump-induced solarization was found to be highly vari able for different crystals and to have an insignificant effect on the laser performance when favorable crystals were used.