Time-domain ptychography
  Through dedicated measurements in the optical regime we demonstrate that ptychography can be applied to reconstruct complex-valued object functions that vary with time from a sequence of spectral measurements. A probe pulse of approximately 1 ps duration, time delayed in increments of 0.25 ps is shown to recover dynamics on a ten times faster time scale with an experimental limit of approximately 5 fs. 
Dirk Spangenberg, Pieter Neethling, Erich Rohwer, Michael H.   Br\"ugmann, Thomas Feurer
physics.optics