A high-power traveling-wave optical parametric amplifier based on MgO:LiNbO<sub>3</sub> that is capable of producing extremely short pulses in the 3-μm spectral range when pumped by a femtosecond Ti:sapphire amplifier near 800 nm has been developed. With seeding by 1-ns pulses from a low-power <i>Q</i>-switched microlaser, we demonstrate idler tunability between 3.1 and 3.9 μm at >10-μJ pulse energy and <200-fs pulse duration. The maximum internal conversion efficiency is 40% for a single pass. The extremely high gain factors achieved permit a more compact solution for the seed source, and we also report on successful seeding with a pulsed laser diode in the femtosecond regime, achieving 5-μJ pulse energy and 130-fs pulse duration near 3.5 μm. We have produced nearly transform-limited 50-fs, 2-μJ pulses near 3 μm with a 1-mm-thick MgO:LiNbO<sub>3</sub> sample by adding a second pass and employing sub-30-fs pumping.
© 1999 Optical Society of America
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.4410) Nonlinear optics : Nonlinear optics, parametric processes
(190.4970) Nonlinear optics : Parametric oscillators and amplifiers
(190.7110) Nonlinear optics : Ultrafast nonlinear optics
(320.7110) Ultrafast optics : Ultrafast nonlinear optics
F. Rotermund, V. Petrov, F. Noack, M. Wittmann, and G. Korn, "Laser-diode-seeded operation of a femtosecond optical parametric amplifier with MgO:LiNbO3 and generation of 5-cycle pulses near 3 μm," J. Opt. Soc. Am. B 16, 1539-1545 (1999)