Attomicroscopy: attosecond electron microscopy

Abstract

The development of Ultrafast Electron Microscopy (UEM) and diffraction (UED) permit the imaging of atomic motion in real time and space. UEM and UED have found a vast range of applications spans chemistry, physics, material science, and biology. The temporal resolution in ultrafast electron imaging, typically on the order of few hundred femtoseconds, is limited by the electron pulse duration and the space charge effect. Hence, imaging the fast motions of electrons remains beyond the reach. Recently, we break the temporal resolution limits in UEM by generating a 30-fs electron pulse exploiting the optical gating approach. The gating technique is based on the electron-laser coupling where the free electrons in the wavepacket exchange energy with the light photons of the laser pulse. In this case, the optical laser pulse acts as a temporal gating for the electrons which gain/loss energy. These electrons are filtered out and generate an electron pulse with a temporal profile similar to the gating laser pulse. The obtained, few tens of femtosecond, temporal resolution opens the door-for the first time-to image the electron dynamics in real time. Moreover, the optical attosecond pulse, which has been demonstrated earlier, eventually will be used to gate the electrons in a sub-femtosecond time window. So, the gated electrons will generate a single isolated attosecond electron pulse. This unique tool will establish the attosecond electron imaging tool which we so-called "Attomicroscopy". Attomicroscopy will enable the imaging of the electron motion, last few hundreds of attosecond to few femtoseconds, in action.