Study of a Tm:Ho:YLF laser pumped by a Raman shifted erbium-doped fibre laser at 1678 nm

The lasing, spectral, and luminescent characteristics of a Tm:Ho:YLF laser pumped by a Raman shifted erbium-doped fibre laser (λ = 1678 nm) into the 1682-nm absorption line of the ³H₆−³F₄ transition of the Tm³⁺ ion are studied. It is shown that the total (with respect to the absorbed power) and slope laser efficiencies upon pulsed pumping reach 46% and 50%, respectively. The output radiation power in the cw regime is 400 mW. The comparative measurements showed that pumping by a fibre laser at 1678 nm is more efficient than diode pumping at 792 nm.