Few-cycle, mJ-level, mid-wave infrared pulses generated via post compression of chirped pulse amplifier

Few-cycle mid-wave infrared pulses were generated by passing a beam from a cryogenically cooled Fe:ZnSe chirped pulse amplifier at a repetition rate of 400Hz through a gas-filled hollow core fiber followed by dispersion compensating bulk calcium fluoride. The krypton-filled fiber at 370kPa yielded 1.14-mJ, 42-fs pulses centered at 4.07-μm, while the oxygen-filled fiber at 310kPa delivered 0.78-mJ, 39-fs pulses spanning 3 to 5.5μm. This work is a step toward a high repetition rate mid-wave infrared driver of isolated attosecond keV x-ray pulses.