Quasi-continuous operation of an LiF laser with $F_2^-$ colour centres

Highly efficient and practically continuous (with an off-duty factor less than 50) operation of an LiF:$F_2^-$ colour-centre laser was observed when it was pumped by radiation from neodymium lasers with an average output power 0.2 – 1.5 W. The use of an Nd$^{3+}$:YLiF$_4$ pump laser emitting at a shorter (1047 nm) wavelength made it possible to reduce the peak value of the threshold pump power to 10 W. Tunable operation of the LiF:$F_2^-$ laser was achieved in the spectral range 1.07 – 1.27 $\mu$m and the efficiency at the maximum of the tuning curve reached 32%.