Efficient passive switches for neodymium lasers made of LiF:F2– crystals

Passive Q switches were made of LiF crystals with F₂^– color centers. These switches were characterized by a 14- to 18-fold contrast between the optical densities in the initial and bleached states, and they had a high initial absorption coefficient of 0.6 cm^–1. The characteristics of one-, two-, and multipulse emission regimes were obtained for a YAG:Nd³⁺ laser (λ = 1.064μ) when LiF:F₂^– switches with different initial transmissions were used. The efficiency in the Q-switching regime depended on the switch transmission and amounted to 50–70% of the efficiency under free-oscillation conditions producing pulses with a peak output power up to 4 MW. The Q-switched radiation pulses were of 25 nsec duration and were characterized by both a high amplitude and a high time stability.