Intense sub-2 cycle infrared pulse generation via phase mismatched cascaded nonlinear interaction in DAST crystal

Octave-spanning, 12.5 fs, (1.9 cycle) pulses with 115 {\mu}J energy in the short-wavelength mid-infrared spectral range (1-2.5 {\mu}m) have been generated via phase-mismatched cascaded nonlinear frequency conversion using organic DAST crystal. Such ultra-fast cascading effect is ensured by the interaction of a pump pulse with the exceptionally large effective nonlinearity of the DAST crystal and experiencing non-resonant, strongly phase mismatched, Kerr-like negative nonlinearity.