Dynamic phenomena occurring on the ultrafast time scales are inherently difficult to image. While pump–probe techniques have been used for decades

probing nonrepeatable phenomena precludes this form of imaging. Additionally

many ultrafast phenomena

such as electron dynamics

exhibit low amplitude contrast in the optical wavelength range and thus require quantitative phase imaging. To better understand the underlying physics involved in a plethora of ultrafast phenomena

advanced imaging techniques must be developed to observe single events at an ultrafast time scale. Here

we present

to the best of our knowledge

the first ptychographic imaging system capable of observing ultrafast dynamics from a single event. We demonstrate ultrafast dynamic imaging by observing the conduction band electron population from a 2-photon absorption event in ZnSe pumped by a single femtosecond pulse. We verify experimental observations by comparing them to numeric solutions of a nonlinear envelope equation. Our imaging method represents a major step forward in ultrafast imaging

bringing the capabilities of ptychography to the ultrafast regime.