Multirod resonators for high-power solid-state lasers with improved beam quality

Many laser applications require high beam quality at high output power and a broad variation of the output power. The ratio of power variation Delta P/sub out/ to beam parameter product theta /sub m/-w/sub m/ for a single rod inside a stable resonator is a constant which depends on the intrinsic crystal parameters and the slope efficiency only. A broad range of the output power causes a large beam parameter product, i.e. a low beam quality. By using several rods inside the same resonator and by a suitable choice of rod position and resonator parameters, the output power range can be increased without reducing the beam quality. In the same way, the beam quality can be improved without reducing the output power. The details of multirod systems are discussed and compared to experimental results.>