Attosecond physics

Abstract

Intense ultrashort light pulses comprising merely a few wave cycles became routinely available by the turn of the millennium. The technologies underlying their production and measurement as well as relevant theoretical modeling have been reviewed in the pages of Reviews of Modern Physics ͑Brabec and Krausz, 2000͒. Since then, measurement and control of the subcycle field evolution of few-cycle light have opened the door to a radically new approach to exploring and controlling processes of the microcosm. The hyperfast-varying electric field of visible light permitted manipulation and tracking of the atomic-scale motion of electrons. Striking implications include controlled generation and measurement of single attosecond pulses of extreme ultraviolet light as well as trains of them, and real-time observation of atomic-scale electron dynamics. The tools and techniques for steering and tracing electronic motion in atoms, molecules, and nanostructures are now becoming available, marking the birth of attosecond physics. In this article these advances are reviewed and some of the expected implications are addressed.

Effects of resonant excitation, pulse duration and intensity on photoelectron imaging of a dianion

“…Hence, this observation is a more general feature of dianions (or indeed MCAs) and depends only on the electric field strength. In neutrals, strong-field ionisation is a well-known phenomenon and has found great application in, for example, 45 high-harmonic generation 40 and attosecond science, 41 where the -1/r Coulomb potential is pulled down sufficiently far in the electric field of the laser that the electron can tunnel out into the continuum. A similar mechanism is likely to be operative in InC 2-, but at significantly lower field strengths.…”

Attosecond tracing of correlated electron-emission in non-sequential double ionization

“…An established technique for resolving one-electron dynamics on subfemtosecond scales involves the use of a strong few-cycle infrared laser field as a clock [1][2][3] . The well-known concept of attosecond streaking spectroscopy has permitted the observation of singleelectron dynamics with attosecond time resolution 4 . Despite this progress, however, the ultrafast dynamics of multiple electrons has resisted direct observation, even though far-reaching conclusions were drawn from kinematically complete strong-field double 5,6 and multiple ionization 7 experiments.…”

Streaking at high energies with electrons and positrons

“…But the opposite condition is fulfilled in the streaking regime and thus the pair production cascade is suppressed [40]. Finally, basic preconditions for streak imaging are that the TP length τ t is shorter than half of the SP wavelength λ s = 2π/ω s , and that the streaking signal exceeds the noise level [1],…”