HIGH-EFFICIENCY GENERATION OF ULTRASHORT 2ND-HARMONIC PULSES BASED ONTHE CERENKOV GEOMETRY

Simultaneous phase- and group-velocity-matched generation of ultrashor t optical second-harmonic pulses based on a quasi-phase-matched Cerenk ov second-harmonic generation scheme is proposed. We compare our schem e with other schemes with respect to its ability to achieve high conve rsion efficiency, its enhancement with respect to cw second-harmonic g eneration, and its sensitivity to waveguide-period fluctuation; ion-ex changed KTP and LiNbO3 waveguides are considered in the evaluation. We believe our proposed scheme is easy to implement, and there is no con straint on crystal length in achieving high efficiency as well as in p reserving an ultrashort pulse width. 100% efficiency is potentially ob tainable from sufficiently long crystals.