Generation of mid-infrared pulses by c(3) difference frequency generation in CaF2 and BaF2
Tunable mid-IR pulses in the range 1300-4200 cm -1 (7.7-2.4 µm) are generated through a phase-matched four-wave mixing process in ordinary mid-IR window materials such as CaF2 and BaF2. In this process the difference frequency v3 =2v2 – v1 is generated from pump fields v1 and v2. The process can be phase matched to different frequencies by adjustment of the angle between the pump fields.