Attomicroscopy: from femtosecond to attosecond electron microscopy

Abstract

In the last decade, the development of Ultrafast Electron Diffraction (UED) and Microscopy (UEM) has enabled the imaging of atomic motion in real time and space. These pivotal table-top tools opened the door for a vast range of applications in different areas of science spanning chemistry, physics, materials science, and biology. We first discuss the basic principles and recent advancements, including some of the important applications, of both UED and UEM. Then, we discuss the recent advances in the field that have enhanced the spatial and temporal resolutions, where the latter, however, is still limited to a few hundreds of femtoseconds, preventing the imaging of ultrafast dynamics of matter on the scale of several tens of femtoseconds. Then, we present our new optical gating approach for generating an isolated 30 fs electron pulse with sufficient intensity to attain a temporal resolution on the same time scale. This achievement allows, for the first time, imaging the electron dynamics of matter. Finally, we demonstrate the feasibility of the optical gating approach to generate an isolated attosecond electron pulse, utilizing our recently demonstrated optical attosecond laser pulse, which paves the way for establishing the field of "Attomicroscopy", ultimately enabling us to image the electron motion in action.Keywords: Attomicroscopy, attosecond electron pulse, 4D electron microscopy, femtosecond electron diffraction, Ultrafast Electron Microscopy, optical gating, imaging the electron motion. electron pulse to hundred femtoseconds; however, they suffer from time jittering and the temporal synchronization issues, which limit the temporal resolution in time-resolved electron experiments. Therefore, the ultrafast dynamics measurements that have been carried out so far are on the timescale of picoseconds to several hundreds of femtoseconds [21][22][23][24][25]. Hence, imaging of faster dynamics (i.e., electron dynamics) in matter still remains beyond reach.Recently, we demonstrated generation of the shortest electron pulse (30 fs) in UEM by the optical gating approach, which breaks the conventional compression limits for an electron pulse and attains electron-dynamics-scale temporal resolution in electron microscopy [26]. In this approach, the generated gated electron pulse duration is limited only by the gating laser pulse, which could be on the attosecond time scale [27]. This approach might eventually lead to the generation of isolated attosecond electron pulses and could open the way for establishing a new "Attomicroscopy" field [26]. It will allow the realtime imaging of electronic motion as theoretically studied in atoms, molecules [28], and condensed matter [29], which could radically change our insight into the workings of the microcosm and could hold the promise for breaking new grounds in a number of fields of science and technology.This review article provides an overview of the developments in the fields of time-resolved electron diffraction and microscopy. The article is structured as follows. Afte...

Single-shot compressed ultrafast photography: a review

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Partially coherent quantum degenerate electron matter waves

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