Compact high-repetition-rate femtosecond laser-driven hard x-ray source

Egbert, A.; Mader, B.; Chichkov, Boris N.; Girardeau-Montaut, J.P.

doi:10.1117/12.450405

Cited by 2 publications

(2 citation statements)

References 12 publications

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“…As an additional consideration, the x-ray or electron source needs to be derived from a master laser oscillator to conserve time synchronization between the excitation or perturbation pulse driving the structural change and the structural probe pulse. Quantum efficiencies (QEs) for generating electron pulses based on photoemission range from QE ≈ 10 −4 for simple metals to about 10 −1 for semiconductor photocathodes [13]; whereas the conversion efficiency for the generation of x-ray photons in 'direct' fs-laser driven plasma sources is typically 10 −6 with several approaches to try to improve it [14][15][16][17][18][19][20]. This efficiency is further reduced by a limited solid angle of collection and x-ray optics by a factor of about 10 −2 at the sample's position.…”

Section: Introduction: Quest For Atomically Resolved Dynamicsmentioning

confidence: 99%

Femtosecond electron diffraction: heralding the era of atomically resolved dynamics

2011

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One of the great dream experiments in Science is to directly observe atomic motions as they occur. Femtosecond electron diffraction provided the first 'light' of sufficient intensity to achieve this goal by attaining atomic resolution to structural changes on the relevant timescales. This review covers the technical progress that made this new level of acuity possible and gives a survey of the new insights gained from an atomic level perspective of structural dynamics. Atomic level views of the simplest possible structural transition, melting, are discussed for a number of systems in which both thermal and purely electronically driven atomic displacements can be correlated with the degree of directional bonding. Optical manipulation of charge distributions and effects on interatomic forces/bonding can be directly observed through the ensuing atomic motions. New phenomena involving strongly correlated electron-lattice systems are also discussed in which optically induced changes in the potential energy landscape lead to ballistic structural changes. Concepts such as the structural order parameters are now directly observable at the atomic level of inspection to give a remarkable view of the extraordinary degree of cooperativity involved in strongly correlated electron-lattice systems. These recent examples, in combination with time-resolved real space imaging now possible with electron probes, are truly defining an emerging field that holds great promise to make a significant impact in how we understand structural dynamics. This article is dedicated to the memory of Professor David John Hugh Cockayne, a world leader in electron microscopy, who sadly passed away in December.

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Section: Introduction: Quest For Atomically Resolved Dynamicsmentioning

confidence: 99%

Femtosecond electron diffraction: heralding the era of atomically resolved dynamics

2011

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“…First, the cross-section for electron scattering is ~ 6 orders of magnitude larger than that for X-ray scattering [10,67]. Second, the quantum efficiencies for generating electron pulses based on photoemission are on the order of 10 −4 and 10 −1 for metals and semiconductor photocathodes, respectively [68], whereas the conversion efficiency for the generation of X-ray photons is typically 10 −6 [69][70][71]. This efficiency is further reduced due to the limited solid angle of collection and X-ray optics by a factor of ~ 10 −2 at the position of the sample.…”

Section: Introductionmentioning

confidence: 99%

Attomicroscopy: from femtosecond to attosecond electron microscopy

Hassan

2018

J. Phys. B: At. Mol. Opt. Phys.

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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...

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Compact high-repetition-rate femtosecond laser-driven hard x-ray source

Cited by 2 publications

References 12 publications

Femtosecond electron diffraction: heralding the era of atomically resolved dynamics

Femtosecond electron diffraction: heralding the era of atomically resolved dynamics

Attomicroscopy: from femtosecond to attosecond electron microscopy

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