GSA and ESA dual-wavelength pumped 2.3 μm Tm:YLF laser on the 3H4→3H5 transition

The population trapping effect of the F34 level is an important factor limiting power scaling 2.3 μm thulium (Tm) laser on H34→H35 transition. In this Letter, we demonstrate a novel scheme ground state absorption (GSA) (H36→H34) and excited (ESA) (F34→H34) dual-wavelength pumped Tm lasers. Introducing ESA pumping process can accurately excite Tm3+ ions accumulated in to H34 level, constructing double populating mechanism for upper H34. A proof-of-principle experimental demonstration GSA (785 nm) (1470 Tm:LiYF4 (Tm:YLF) was realized. maximum continuous-wave output 1.84 W at 2308 nm achieved under 785 1470 pumping, increased by 60% compared with case single-wavelength same resonator condition. Our work provides efficient way achieve higher from Tm-doped lasers