Efficient second harmonic generation of femtosecond laser at one micron

By using spectrally noncritical phase-matching in a partially deuterated KDP around its retracing point of phase-matching, we have experimentally and numerically investigated the characteristics of second-harmonic generation (SHG) with femtosecond laser at 1 microm for the first time. This phase-matching configuration can support efficient SHG over 20nm bandwidth of the fundamental laser at 1 microm in a 10-mm-long crystal. Efficiency of harmonic conversion as high as 55% has been demonstrated.