Tunable mid-IR pulses in the range 1300–4200 cm<sup>-1</sup> (7.7–2.4 µm) are generated through a phase-matched four-wave mixing process in ordinary mid-IR window materials such as CaF<sub>2</sub> and BaF<sub>2</sub> . In this process the difference frequency <i>v</i><sub>3</sub>=2<i>v</i><sub>2</sub>-<i>v</i><sub>1</sub> is generated from pump fields <i>v</i><sub>1</sub> and <i>v</i><sub>2</sub> . The process can be phase matched to different frequencies by adjustment of the angle between the pump fields.
© 2001 Optical Society of America
(140.3070) Lasers and laser optics : Infrared and far-infrared lasers
(160.4330) Materials : Nonlinear optical materials
(190.4380) Nonlinear optics : Nonlinear optics, four-wave mixing
(320.7110) Ultrafast optics : Ultrafast nonlinear optics
Han-Kwang Nienhuys, Paul C. M. Planken, Rutger A. van Santen, and Huib J. Bakker, "Generation of mid-infrared pulses by X(3) difference frequency generation in CaF2 and BaF2," Opt. Lett. 26, 1350-1352 (2001)