抄録
We present a simple concept for high-power microchip lasers by employing edge-pumped scheme for Yb: YAG core and YAG clad composite structure. Continuous-wave (CW) output power was up to 90 W from a 400-μmthick diffusion bonded Yb: YAG/YAG structure with a 10 at.% Yb: YAG square core of 2×2 mm2; the slope efficiency and optical-to-optical efficiency with respect to the pump power were 40% and 28%, respectively. Measurements of the optical phase distortions induced by pumping gives a focus shift bellow 0.05 m and shows the absence of astigmatic effects, indicating the axial heat flow in this pumping configuration. The newly developed microchip has circular, Yb: YAG single crystal core with 5mm-diameter, surrounded by transparent, undoped YAG ceramic pump wave-guide. Near 900 W pump light from fourfold stack with 6 diodes directly coupled to the edge windows of the ceramic wave-guide with 300μm-thickness. Output powers of 380 W (peak) was reached in quasi-continuous-wave (QCW)(10ms, 10Hz) operation. lmproved slope efficiencies and optical conversion were 50% and 44%, respectively.
