Long-pulse generation with a stable-relaxation-oscillation Nd:YLF laser

A simple technique for long-pulse (0.2-2 microsec) generation with neodymium lasers has been demonstrated. Under the proper conditions, a normal-mode oscillator, operated in a single transverse mode, produces well-defined relaxation oscillations from which a single subpulse can be isolated for amplification. The characteristic subpulse temporal profile is ideal for saturated amplification without pulse shortening. Data are presented for a Nd:YLF system consisting of an oscillator followed by a 64-nm-long amplifier. Pulse energies in excess of 100 mJ were achieved with a small-signal gain of 630.