We measure the efficiency of converting high-power 15-fs 0.8-μm pulses to the mid infrared in GaAs and GaSe as well as the pulse duration and the spectrum of the infrared radiation that is produced. Free-carrier production limits the conversion efficiency in GaAs to approximately 5×10<sup>-7</sup> , allowing us to produce 2.5-pJ, 30-fs pulses spanning the spectral range from 6 to 14 μm . In GaSe we obtain, in a moderately saturated regime, a conversion efficiency of 7.5×10<sup>-5</sup> , limited by two-photon absorption, allowing us to produce pulses of 100-fs duration containing 10 nJ of energy.
© 2001 Optical Society of America
(190.0190) Nonlinear optics : Nonlinear optics
(190.2620) Nonlinear optics : Harmonic generation and mixing
(320.0320) Ultrafast optics : Ultrafast optics
(320.7090) Ultrafast optics : Ultrafast lasers
(320.7110) Ultrafast optics : Ultrafast nonlinear optics
J.-P. Likforman, M. Mehendale, D. M. Villeneuve, M. Joffre, and P. B. Corkum, "Conversion of high-power 15-fs visible pulses to the mid infrared," Opt. Lett. 26, 99-101 (2001)