Envelope time reversal of optical pulses following frequency conversion   with accelerating quasi-phase-matching
  It is shown theoretically that the use of accelerating spatiotemporal quasi-phase-matching (QPM) modulation patterns in media with parametric optical interactions makes it possible to generate a time-reversed replica of the pump pulse envelope in a frequency converted signal. The conversion is dependent on the group-velocity mismatch between the fundamental and up-converted harmonics, and controlled by the acceleration rate (chirp) of the QPM phase pattern. Analytical results are corroborated by numerical simulations. 
Michal Yachini, Boris Malomed, Alon Bahabad
physics.optics nlin.PS