Attosecond metrology

Abstract

The generation of ultrashort pulses is a key to exploring the dynamic behaviour of matter on ever-shorter timescales. Recent developments have pushed the duration of laser pulses close to its natural limit-the wave cycle, which lasts somewhat longer than one femtosecond (1 fs = 10-15 s) in the visible spectral range. Time-resolved measurements with these pulses are able to trace dynamics of molecular structure, but fail to capture electronic processes occurring on an attosecond (1 as = 10-18 s) timescale. Here we trace electronic dynamics with a time resolution of </= 150 as by using a subfemtosecond soft-X-ray pulse and a few-cycle visible light pulse. Our measurement indicates an attosecond response of the atomic system, a soft-X-ray pulse duration of 650 +/- 150 as and an attosecond synchronism of the soft-X-ray pulse with the light field. The demonstrated experimental tools and techniques open the door to attosecond spectroscopy of bound electrons.

Extreme-ultraviolet light generation in plasmonic nanostructures

“…This facilitates the access to ultrashort, extreme-ultraviolet light pulses at laboratory scales [33,34,35] and makes HHG valuable for novel experimental realizations such as attosecond spectroscopy [22,23] or nanoscale photonic imaging [21].…”

MAKING OPTICAL WAVES, TRACING ELECTRONS IN REAL-TIME: THE ONSET OF THE ATTOSECOND REALM (Invited Review)

“…It was however, not before few-cycle pulses were employed in the study of strong field phenomena that relevant dynamics were confined to occur in a fraction of a field-cycle, opening the way to the attosecond realm. Although precise CEP stability was absent in these early works [23,24] additional nonlinearity contributed by the propagation of the intense driver in the strongly ionized medium [25] assisted the isolation of highly energetic (E > 90 eV) attosecond pulses [24] and their subsequent use in tracing physical processes such as the atomic Auger decay in real-time [26].…”

“…Replacing metal anodes by atoms and the fast rising electric field of a capacitor by that of an optical waveform, attosecond streaking was the first technique ever to port the well-known concept of streak cameras from the picosecond to the attosecond domain. Even though first hinds of the key ideas behind attosecond streaking can be recognized in earlier experiments [23,24], it was the implementation of the technique by CEP controlled few-cycle pulses that boosted resolution to characterize attosecond electron photoemission with a resolution below 100-as [40]. Further advancement provided access to ever shorter x-ray pulses [41] nearing to the atomic unit of time [42].…”

LUX: a design study for a linac-/laser-based ultrafast x-ray source

“…Until now, ultrafast time domain studies in the x-ray region have been lacking. By use of synchrotron radiation and by novel conversion of intense laser pulses into soft and hard x-rays, scientists have been able to perform some of the first innovative experiments recently, such as Bragg diffraction studies of phase transitions, timeresolved Laue diffraction of myoglobin-CO reversible binding, femtosecond photoelectron spectroscopy, and even attosecond electron redistribution in Auger electron processes [7][8][9][10]. However, these laser-based x-ray fluxes are low, the signal levels weak, the synchrotron-based signals have long pulse durations, and experiments are challenging to accomplish by individual scientists.…”

“…Access to the sub-femtosecond domain offers great potential of opening a new area of science, studying phenomena on the timescales of electronic transitions [10].…”