Generation of Sub 50-fs Mid-Infrared Pulses by Optical Parametric Amplifier Based on Periodically-Poled MgO:LiNbO_3

摘要

Femtosecond pulses with the bandwidth in excess of 600 nm in 3-4μm spectral range were generated by an optical parametric amplifier based on periodically-poled MgO:LiNbO_3. We utilized broadband quasi-phase-matching condition, which appears around the idler wavelength of 3400 nm when pumped at 800 nm. The generated mid-infrared pulses were characterized by the frequency-resolved optical gating method in the second-harmonic generation geometry. After the second-order spectral phase was compensated by dispersive transmission through a silicon window, the pulse duration was about 45 fs, corresponding to four optical cycles. Compensation of higher-order spectral phase could enable the generation of few-cycle pulses.