The measurement of internal losses in 4-level lasers

In this paper we report on a continuous-wave and electro-optically (EO) Q-switched Ho-doped lutetium vanadate (Ho:LuVO4) laser dual end-pumped by two laser diodes at 1.94 µm. Under continuous-wave regime, a maximum output power of 18.8 W at 2058.1 nm was achieved with absorbed pump power of 44.7 W, corresponding to a slope efficiency of 54.1 % with respect to the absorbed pump power. By using a langasite (La3Ga5SiO14, LGS) crystal as the EO Q-switch, at a pulse repetition frequency of 3 kHz, the EO Q-switched Ho:LuVO4 laser produced a maximum pulse energy of 3.2 mJ and a minimum pulse width of 8.9 ns, resulting in a peak power of 358.8 kW.