Efficient visible laser operation of Tb:LiYF<sub>4</sub> and LiTbF<sub>4</sub>
Hengjun Chen, Hiroki Uehara, Hiroki Kawase, Ryo Yasuhara
Abstract
We report laser operation of two Tb 3+ -activated gain media, Tb:LiYF 4 and LiTbF 4 , in yellow or/and green spectral region. A record-high slope efficiency of 63% among Tb 3+ -lasers and maximum output power of 1.17 W (incident power of 2.79 W) at around 544 nm were obtained with a c-cut 15%Tb:LiYF 4 crystal. The yellow laser characteristics in σ-polarization were studied. A slope efficiency of 21% at 582 nm was achieved. More importantly, we succeeded in laser operation of LiTbF 4 for the first time to the best of our knowledge. Laser oscillation at around 544 nm yielded a maximum slope efficiency of 45%. This points toward the possibility of producing high-energy pulsed lasers using LiTbF 4 , which features a high active-ion concentration as well as relatively long lifetime.