High-Radiance Optically Pumped Semiconductor Disk Lasers

We report on high-power operation of an optically pumped external-cavity semiconductor disk laser. 13.2W optical output power at 970 nm has been achieved in a double-pass pump configuration. The laser Bragg mirror was designed to provide not only high reflectivity for the laser wavelenth but also for the pumping beam. A proper layer structure which supports standing-wave patterns with a node near the semiconductor surface reduces cavity losses and degradation. Compensation of the compressive strain, introduced by the six InGaAs quantum wells is achieved by GaAsP layers. The influence of the cavity geometry and the pump spot size on the laser beam quality and optical output power is investigated. An extention of the well-known equation is presented and compared to experimental results.