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

Fei Wang; Haitao Huang; Haiwei Chen; Yushuo Bao; Zihan Li; Deyuan Shen

doi:10.3788/COL202119.091405

Abstract

The population trapping effect of the

{{}^{3}F}_{4}

level is an important factor limiting the power scaling of the 2.3 μm thulium (Tm) laser on the

{{}^{3}H}_{4} \to {{}^{3}H}_{5}

transition. In this Letter, we demonstrate a novel scheme of ground state absorption (GSA) (

{{}^{3}H}_{6} \to {{}^{3}H}_{4}

) and excited state absorption (ESA) (

{{}^{3}F}_{4} \to {{}^{3}H}_{4}

) dual-wavelength pumped 2.3 μm Tm lasers. Introducing an ESA pumping process can accurately excite the

{Tm}^{3 +}

ions accumulated in the

{{}^{3}F}_{4}

level to the

{{}^{3}H}_{4}

level, constructing a double populating mechanism for the upper laser level

{{}^{3}H}_{4}

. A proof-of-principle experimental demonstration of the GSA (785 nm) and ESA (1470 nm) dual-wavelength pumped 2.3 μm

Tm : {LiYF}_{4}

(Tm:YLF) laser was realized. A maximum continuous-wave output power of 1.84 W at 2308 nm was achieved under 785 and 1470 nm dual-wavelength pumping, increased by 60% compared with the case of 785 nm single-wavelength pumping under the same resonator condition. Our work provides an efficient way to achieve higher output power from 2.3 μm Tm-doped lasers on the

{{}^{3}H}_{4} \to {{}^{3}H}_{5}

transition.