Alexandrite laser passive Q -switching and spectral output enhancing up to 0.7 ÷ 1.15 p,m

The nature of the absorption band at 780 nm (at 300 K) in radiationally colored LiF crystals was investigated. It was shown that this absorption band formed under thermal annealing of LiF : F 3 − crystals completely coincides with the absorption band of N 1 − centers that were created by recharging of the neutral N1 centers under low-temperature electron reirradiation of the LiF crystal.