FUNDAMENTAL-FREQUENCY PULSE-COMPRESSION THROUGH CASCADED 2ND-ORDER PROCESSES IN A TYPE-II PHASE-MATCHED 2ND-HARMONIC GENERATOR

We show that cascading of the second-order processes under large group -velocity mismatch can lead to the efficient compression of pulses at fundamental frequency in the type II phase-matched second-harmonic-gen eration process. We demonstrate that any of three interacting pulses c an be compressed if thee proper ratio of intensities of the o- and e-p olarized pump pulses is chosen on input. We experimentally achieved co mpression of o-polarized pulses from 1.3 ps down to 280 fs with energy conversion close to 50%. when a conventional second-harmonic compress or with unbalanced intensities of the pump pulses was used. (C) 1996 O ptical Society of America