EFFICIENT CONVERSION OF PICOSECOND LASER-PULSES INTO 2ND-HARMONIC FREQUENCY USING GROUP-VELOCITY DISPERSION

A computer model has been used to investigate frequency doubling of 1-psec duration high-power pulses in potassium dihydrogen phosphate (KDP) for type-II phase matching. It has been found that group-velocity dispersion can be used to advantage by predelaying the ordinary and extraordinary polarizations appropriately in a thin KDP crystal with its axes aligned at 90°to the main conversion crystal. In that situation power conversion >100% from the fundamental to the second harmonic can be obtained with simultaneous compression of the output pulse duration by up to a factor of 5. © 1990 The American Physical Society.