183 W, M/sup 2/=2.4 Yb:YAG Q-switched laser

Summary form only given. The small quantum defect of Yb:YAG and the concomitant reduction in thermal lensing and birefringence relative to Nd:YAG makes these lasers attractive as potential high power, high brightness radiation sources, such as required for military and materials processing applications. One laser architecture which is well suited to quasi-three level laser ions such as Yb/sup 3+/, uses a lens duct to deliver pump light from a microlensed diode array to the end of a laser rod. We describe a Yb:YAG laser incorporating the diode array end-pumping architecture with a hollow lens duct for diode pump delivery, passing the laser beam through a spacer separating the two halves of the diode array.