Spectroscopy and laser operation of Sm3+-doped lithium lutetium tetrafluoride (LiLuF4) and strontium hexaaluminate (SrAl12O19)

We report on laser operation in the orange and red spectral range in samarium (Sm3+)-doped fluoride and oxide crystals at 300 K. Sm3+-doped LiLuF4 (LLF) and SrAl12O19 (SRA) crystals were grown by the Czochralski-technique and utilized for spectroscopic investigations and laser experiments. The spin-forbidden transitions of Sm3+ exhibit low cross sections the order of 10(-21) cm(2), but high radiative upper state lifetimes of several ms in both crystal systems. Under 2.-OPSL-pumping at 480 nm, orange laser operation was achieved with Sm:LLF and Sm, Mg:SRA at lasing wavelengths of 606 nm and 593 nm, respectively. Furthermore laser oscillation was demonstrated at 648 nm in the red and 703 nm in the deep red spectral range with Sm: LLF and Sm, Mg: SRA, respectively. Output power levels of several 10mW were obtained at slope efficiencies of up to 15 %. Most of the realized lasers were operating in a strongly modulated or even self-pulsing regime. (C) 2015 Optical Society of America