A novel injection and switchout scheme for multipass laser amplifiers

A novel injection and switchout scheme for multipass laser amplifiers is described. The method utilizes noncollinear difference frequency generation for injection and harmonic generation for switchout. Both injection and switchout are accomplished in the same crystal. The scheme is passive, avoids leakage through mirrors or electrooptic switching, and optically isolates the seed pulse generator from any stray light from the amplifier.