Ultra high resolution 4-D spatio-temporal imaging using intense laser pulses



X-ray diffraction and electron microscopy have been the conventional means for imaging matters to achieve spatial resolution of better than the atomic scale (Angstroms) for long time.Recently, various methods capable of resolving the temporal as well as the spatial information have been developed to analyze matter transitions. New techniques for imaging transient matters with higher temporal resolutions are growing increasingly desirable. In this project, we will develop theoretical and computational methods for high resolution 4-D spatio-temporal imaging of atoms and molecules using intense ultrashort infrared laser pulses. Spatial resolution of the atomic scale (Angstroms) and temporal resolution of the order of the electron orbital period in molecules (atto seconds) can be achieved using rescattering electrons produced from molecules exposed to intense laser pulses (See Figure 1). This new technique should open up a route to the time-resolved study of electron dynamics in matter transition and promote deeper understanding of the laser-matter interaction.





Schematic of chemical imaging with infrared lasers. (a) The electric field (E) and the vector potential (A) of a typical five-cycle infrared laser pulse. (b) Schematic of using backward rescattering process to image the molecule by its own electron. First, the electron gets tunnel ionized near "a" at the peak of the electric field. It returns to recollide with the target near "b" which corresponds to the peak of the vector potential and get scattered backward to imprint the target structure on the detector. Electrons ionized near "a' " instead would imprint the image on a detector on the left (not shown).



Toru Morishita,UEC