High-efficiency high-power UV generation at 2128 Å in urea

Urea has been found to be phase matchable for type-1 fifth-harmonic generation by mixing the Nd:YAG laser fundamental and fourth-harmonic radiation at room temperature. A peak power as high as 4.5 MW with an average power of 320 mW was obtained at 2128 Å in a 5 mm long crystal.