Continuous-wave 1.50-microm thulium cascade laser.

A cascade laser scheme is used to obtain continuous-wave 1.50-microm laser emission at room temperature on the normally self-terminating Tm(3+)(3)H(4) ? (3)F(4) transition in YLiF(4). The long-lived (3)F(4) state is quenched through energy transfer to the Ho(3+)(5)I(7) state, which is depopulated through the Ho(3+)(5)I(7) ? (5)I(8) 2.06-microm laser transition.