Simple high-efficiency TEM(00) diode-laser-pumped Q-switched laser

A simple, efficient diode-laser-pumped Q-switched Nd:YAG laser is described that produces 2.25-mJ, TEM(00), 4-ns pulses up to 90 Hz with only 20 mJ of pump power. The laser has a zigzag slab geometry, side pumped with only one high-power quasi-cw diode bar. This performance approaches that of longitudinal pumping, demonstrating TEM(00) mode operation with long-pulse and Q-switched slope efficiencies of 28% and 19%, respectively. Secondand fourth-harmonic efficiencies of >50% and >20% from 1064 nm without the use of external focusing optics were also demonstrated.