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Femtosecond

About: Femtosecond is a research topic. Over the lifetime, 35106 publications have been published within this topic receiving 691405 citations. The topic is also known as: 1 E-15 s & fs.


Papers
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Journal ArticleDOI
TL;DR: In this article, active switching of plasmons by an external magnetic field was demonstrated in a metal-ferromagnet-metal structure and the strong modulation, combined with possible all-optical magnetization reversal induced by femtosecond light pulses, opened the door to ultrafast magneto-plasmonic switching.
Abstract: Active switching of plasmons by an external magnetic field is demonstrated in a metal–ferromagnet–metal structure. The strong modulation, combined with possible all-optical magnetization reversal induced by femtosecond light pulses, opens the door to ultrafast magneto-plasmonic switching.

474 citations

Journal ArticleDOI
TL;DR: In this article, the temporal contrast of femtosecond (F2F) laser reflectors was investigated and it was shown that high-order harmonics of the laser frequency can be generated through two distinct mechanisms.
Abstract: Specular reflection is one of the most fundamental processes of optics. At moderate light intensities generated by conventional light sources this process is well understood. But at those capable of being produced by modern ultrahigh-intensity lasers, many new and potentially useful phenomena arise. When a pulse from such a laser hits an optically polished surface, it generates a dense plasma that itself acts as a mirror, known as a plasma mirror (PM). PMs do not just reflect the remainder of the incident beam, but can act as active optical elements. Using a set of three consecutive PMs in different regimes, we significantly improve the temporal contrast of femtosecond pulses, and demonstrate that high-order harmonics of the laser frequency can be generated through two distinct mechanisms. A better understanding of these processes should aid the development of laser-driven attosecond sources for use in fields from materials science to molecular biology.

473 citations

Journal ArticleDOI
TL;DR: It is shown that an efficient novel channel for angular momentum dissipation to the lattice can be opened by femtosecond laser excitation of a ferromagnet, and for the first time, the quenching of spin angular momentum and its transfer toThe lattice with a time constant of 120+/-70 fs is determined unambiguously with X-ray magnetic circular dichroism.
Abstract: The rapidly increasing information density required of modern magnetic data storage devices raises the question of the fundamental limits in bit size and writing speed At present, the magnetization reversal of a bit can occur as quickly as 200 ps (ref 1) A fundamental limit has been explored by using intense magnetic-field pulses of 2 ps duration leading to a non-deterministic magnetization reversal For this process, dissipation of spin angular momentum to other degrees of freedom on an ultrafast timescale is crucial An even faster regime down to 100 fs or below might be reached by non-thermal control of magnetization with femtosecond laser radiation Here, we show that an efficient novel channel for angular momentum dissipation to the lattice can be opened by femtosecond laser excitation of a ferromagnet For the first time, the quenching of spin angular momentum and its transfer to the lattice with a time constant of 120+/-70 fs is determined unambiguously with X-ray magnetic circular dichroism We report the first femtosecond time-resolved X-ray absorption spectroscopy data over an entire absorption edge, which are consistent with an unexpected increase in valence-electron localization during the first 120+/-50 fs, possibly providing the driving force behind femtosecond spin-lattice relaxation

468 citations

Journal ArticleDOI
TL;DR: In this article, a pump-supercontinuum-probe (PSCP) spectroscopy with femtosecond time resolution was developed theoretically and experimentally, and it was shown that the supercontinuum can be described as a single chirped pulse.
Abstract: Pump--supercontinuum-probe (PSCP) spectroscopy with femtosecond time resolution is developed theoretically and experimentally. The connection to previous theoretical results on nonchirped probing is established. It is experimentally shown that the supercontinuum can be described as a single chirped pulse. A key problem of the technique---the precise time correction of transient spectra---is solved by monitoring the nonresonant electronic response from a pure solvent (liquids) or from a transparent substrate (solid films). This allows for an adequate characterization of the supercontinuum, in particular, for directly measuring the spectral dependence of the pump-probe cross correlation. For 50-fs pump pulses, a theoretical estimate gives an accuracy for the time correction of 10 fs, which is typically \ensuremath{\approx}1/30 of the supercontinuum pulse duration. Hence a time resolution of 10--20 fs can be experimentally realized. Contributions to the nonresonant transient signal from high-frequency Raman excitations and from low-frequency impulsive-stimulated Raman processes are discussed. The PSCP technique is illustrated by results from experiments with fused silica and several common solvents and with a chromophore in solution.

464 citations

Journal ArticleDOI
TL;DR: In this article, the localization and solvation of excess electrons in pure water have been resolved at the femtosecond time scale, where the electron thermalizes and reaches in 110 fs a localized state absorbing in the infrared.
Abstract: The localization and solvation of excess electrons in pure water have been resolved at the femtosecond time scale. Before it becomes solvated, the electron thermalizes and reaches in 110 fs a localized state absorbing in the infrared. This transient species with lifetime 240 fs has been postulated to exist but has not been observed previously in liquid water.

464 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,403
20223,116
20211,239
20201,571
20191,715
20181,651