Spectroscopic characterization of a Tm3+: SrGdGa3O7 crystal

Absorption, excitation, and emission spectra of trivalent thulium in SrGdGa 3O7 crystal have been recorded at room temperature and at approximately 8K. Room-temperature luminescence lifetimes of D-1(2), (1)G(4), H-3(4), and F- 3(4) states have been measured for Tm concentration ranging from 0.5 at. % to 9 at. %. Based upon these data the crystal field splitting of luminescen t states has been derived and radiative transitions rates have been evaluat ed. Strong self-quenching of luminescence originating in the (1)G(4) and H- 3(4) states has been found in this activator-host combination. Peak emissio n cross section of the potential laser transition at 1800 nm was determined to be 3.9 x 10(-21) cm(2) and the gain coefficient versus wavelength was e stimated and discussed.