title: Sub-four-cycle laser pulses directly from a high-repetition-rate optical parametric chirped-pulse amplifier at 3.4 μm.
abstract: We generate sub-four-cycle pulses (41.6 fs) with 12 μJ of pulse energy in the mid-infrared spectral range (center wavelength 3.4 μm) from a high-repetition-rate, collinear three-stage optical parametric chirped-pulse amplifier (OPCPA) operating at 50 kHz. Apodized aperiodically poled MgO:LiNbO3 crystals with a negative chirp rate are employed as gain media to achieve ultrabroadband phase-matching while minimizing optical parametric generation. The seed pulses are obtained via a 1.56 μm femtosecond fiber laser, which is spectrally broadened in a dispersion-shifted telecom fiber to support 1000 nm bandwidth idler pulses in the mid-infrared.
authors.forename: B W
authors.initials: BW
authors.lastname: Mayer
authors.forename: C R
authors.initials: CR
authors.lastname: Phillips
authors.forename: L
authors.initials: L
authors.lastname: Gallmann
authors.forename: M M
authors.initials: MM
authors.lastname: Fejer
authors.forename: U
authors.initials: U
authors.lastname: Keller