Nanosecond and microsecond pulse generation in solid-state lasers (review)

The temporal characteristics of Q-switched laser pulses are considered. The dependences are given of the duration (Δτ) and shape of pulses from solid-state lasers, operating in the giant-pulse regime, on the active-medium and resonator parameters, and the possibilities of varying Δτ over the range 10^–9–10^–6 sec are considered. Attention is concentrated on the possibilities of increasing the duration of a pulse to 1 μsec and more. Theoretical and experimental results are presented on the subject of increasing the pulse duration by introducing, into the laser cavity, electro-optic negative feedback or nonlinear losses caused by two-photon absorption in semiconductors, stimulated Raman scattering, and second harmonic generation. Methods are also considered of reducing Δτ for a giant pulse to 10^–9 sec or less.