Femtosecond mid-infrared laser pulses that are continuously tunable in the wavelength range from 9 to 18 μm are demonstrated. These nearly bandwidth-limited pulses are generated by phase-matched difference-frequency mixing within the broad spectrum of 20-fs pulses from a mode-locked Ti:sapphire laser in GaSe. A direct determination of the pulse duration at 11.5 μm gives a value of 140 fs. The average mid-infrared power of 1 μW is ∼100 times greater than that for infrared generation by non-phase-matched optical rectification.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics