Continuous-wave laser action around 2-μm in Ho^3+:Lu_2SiO_5

Abstract

Continuous-wave (cw) laser action around 2 microm in Ho(3+)-doped Lu(2)SiO(5) (LSO) was demonstrated in this paper. Cryogenically cooled by liquid nitrogen, a 10-mm long Tm-sensitized (6% at.) Ho(0.4% at.):LSO produced a maximum output power of 3 W at 2.07 microm for incident diode power of 11 W at 786 nm, and a slope efficiency of 35% with respect to incident pump power. To achieve room-temperature operation of Tm, Ho:LSO laser, a 1-mm long microchip crystal was pumped by a high brightness diode, generating an output power of greater than 80 mW and a slope efficiency of 26% at 2.08 microm. Using a 1.91 microm Tm:YLF laser as an in-band pump source, room-temperature cw operation of singly-doped Ho: Lu(2)SiO(5) laser at 2106 nm was attained with a maximum output power of 2.8 W and a slope efficiency of 35% corresponding to absorbed pump power.