Efficient generation of coherent blue light byfrequency-tripling single1.32 µm beam in two separate KTP and Ce-doped KTP crystals

Efficient blue light generation at 0.44 µm has been achieved by phase-matched frequency-doubling in an undoped KTiOPO4 crystal and subsequent sum-frequency generation in a cerium-doped KTiOPO4 crystal by using a single 1.32 µm pump beam. An overall frequency-tripling conversion efficiency of 5.9% has been achieved at a pump pulse energy of 140 µJ.