Thin Disk Laser Operating in Fundamental Mode up to a Power of 4kW

Fundamental mode lasers at high power are desirable to accommodate many industrial and scientific applications especially in pulsed mode of operation. Due to its unique properties the thin disk laser (TDL) concept is an ideal platform for the generation of high optical power with excellent beam quality. Reliability, low brightness constraints for the pump source, insensitivity to back reflections, negligible nonlinearities, high scalability are a few inherent properties, and thus TDLs have been widely used in industrial applications. In the past there have been many efforts to reach the maximum output power keeping the beam quality close to the diffraction limit. Piehler et al. [1] recently demonstrated 1.1 kW with M ² <; 1.3 using adaptive optics inside the resonator whereas Peng et al. [2] achieved 1.1 kW with M ² <; 1.4 by evacuating the laser resonator. 4 kW with M ² <; 1.4 have been shown in [3] by optimizing the resonator design for a specific operation point in the stability zone.