Demonstration of high efficiency third harmonic conversion of high power Nd-glass laser radiation

We report on efficient conversion from 1.054 μm to 0.35 μm by third harmonic generation in two Type II KDP crystals. Energy conversion efficiencies of up to 80% have been measured under conditions applicable to large glass laser systems. A new tripling scheme used for these experiments requires a minimum of optical components and is insensitive to exact crystal alignment and laser beam divergence. A convenient scaling law allows tripling optimization for many different laser conditions.