Spectral composition of the radiation emitted from a concentrated LiNdLa phosphate glass laser with a $Q$ switch made of an LiF crystal with $F_2^-$ centers

An investigation was made of the emission spectrum of a concentrated LiNdLa phosphate glass laser with $Q$ switching in an LiF crystal containing $F_2^-$ color centers. In the absence of selection the spectral width was $\sim$4.0 cm$^{-1}$. The use of a resonant reflector as the exit mirror of the laser ensured single-frequency emission with a probability of 70%. Similar investigations were carried out also on an YAG:Nd$^{3+}$ laser.