2.3–2.5 μm laser operation of LD-pumped Tm:YAP on the 3H4→3H5 transition

Abstract 2.3–2.5 μm laser operation of LD-pumped Tm:YAP on the 3H4→3H5 transition is reported. The a-cut, b-cut and c-cut Tm:YAP crystals with 2 at.% doping concentration were used to characterize the laser performance. All the laser outputs were found to be linearly polarized that is induced by the gain anisotropy of Tm:YAP. First laser oscillation of Tm-doped laser on the 3H4→3H5 transition beyond 2.4 μm in Tm:YAP was realized by using a specially designed output coupler with a high transmittance at 2200–2350 nm and partial reflection at 2400–2500 nm. 736 mW at 2446 nm and 189 mW at 2482 nm are obtained from the a-cut and b-cut crystal, respectively. Furthermore, continuous-wave and passively Q-switched dual-wavelength Tm:YAP laser at 2274 and 2383 nm were realized with the a-cut crystal. 538 mW at 2353 nm with a slope efficiency of 8.3% is achieved from the c-cut crystal. Our work demonstrates the multi-wavelength emitting ability of LD-pumped Tm:YAP laser on the 3H4→3H5 transition, which can further expand the application of Tm-doped lasers.