Ultraviolet solid-state Ce:YLF laser at 325 nm

We describe the first reported observation of stimulated emission from a 5d-4f transition in a triply ionized rare-earth-doped crystal. Ce(+3) ions in LiYF(4) (YLF), optically pumped at 249 nm, emitted at 325.5 nm, the shortest wavelength yet obtained from an optically pumped solid-state laser. The large fluorescence linewidth of the laser transition makes the Ce:YLF laser a potentially tunable source of coherent near-ultraviolet radiation between 305 and 335 nm.