A helically pumped disc laser amplifier

The first laser pellet fusion approaches emphasized inertial confinement with heating by nanosecond laser pulses. The large energy required for breakeven with this approach has led more recent research to concentrate on pellet compression approaches which result in more realizable energy requirements but also demand shorter pulse durations ( sec). Self focusing dominates in this latter time regime and changes the optimum point for conversion from rod to disc amplifiers. In the course of reoptimizing a CGE VD-640 for subnanosecond operation it became clear that it was worthwhile to consider a helically pumped disc amplifier rather than linear pumping geometries. This paper compares the operation of a helically pumped 43 mm aperture disc amplifier to an equivalent linearly pumped amplifier as well as to an equivalent rod amplifier.