The study of a Tm:YLF laser pumped by a Raman shifted Erbium fiber laser at 1678Â nm

► Tm:YLF laser pumped at 1.678 um was studied at two (1.5% and 5%) ion concentrations. ► At output power up to 460 mW measured lasing slope efficiency was as high as 55%. ► Temporal structure of a beam represents series of peaks of relaxation oscillations. ► Lasing performance was compared to that obtained under pumping by 792-nm laser diode. ► Beam quality (M2) was measured for both pumping channels and two concentrations of Tm.