  The physics of strong-field applications requires driver laser pulses that
are both energetic and extremely short. Whereas optical amplifiers, laser and
parametric, boost the energy, their gain bandwidth restricts the attainable
pulse duration, requiring additional nonlinear spectral broadening to enable
few or even single cycle compression and a corresponding peak power increase.
In the mid-IR wavelength range that is critically important for scaling the
ponderomotive energy in strong-field interactions, we demonstrate a remarkably
simple energy-efficient and scalable soliton-like pulse compression in a
mm-long YAG crystal with no additional dispersion management. Sub-three-cycle
pulses with >0.65 TW peak power are compressed and extracted before the onset
of modulation instability and multiple filamentation as a result of a favorable
interplay between strong anomalous dispersion and optical nonlinearity around
the wavelength of 3900 nm. As a striking manifestation of the increased peak
power, we show the evidence of mid-infrared pulse filamentation in atmospheric
air.
