This issue features papers from the Extreme Light Infrastructure (ELI) project and expanded papers based on results presented at the 6th International Conference on Attosecond Physics (ATTO 2017), as well as contributions from the broader international community on the attosecond science and technology.
© 2018 Optical Society of America
The generation of attosecond laser pulse in 2001 opened a door that revealed the dynamics in the timescale of electron motion in atoms, which has enabled us to explore laser–matter interaction in unprecedented detail. Up to now, the main technology to realize attosecond flash has relied on strong field ionization using a femtosecond laser, corresponding to the high-order harmonic generation (HHG) in the frequency domain. To obtain an isolated attosecond laser pulse, new schemes, such as polarization gating (PG), double optical gating (DOG), and general double optical gating (GDOG), were developed following amplitude gating (AG). The application of such forms of radiation promises to offer a formidable tool for the experimental investigation of ultrafast processes in multi-electron systems. The collective electronic motion in such complex systems and the electron correlation mechanisms represent fundamental problems in atomic and molecular physics, from both a theoretical and an experimental point of view.
In the last decade, the shortest flash pulse was pushed to the range of sub-100-as. After the 80-as pulse was generated at MPQ with the AG scheme in 2008, a 67-as result was further obtained with the DOG scheme at UCF in 2012. As is well known, the cutoff frequency of HHG has quadratic dependence on the wavelength of the driven laser; therefore, a new trend is to use an infrared femtosecond laser for HHG, which will support higher photon energy and even shorter attosecond pulses. In the last year, the world record leaped to 53 as and 43 as in succession through the use of a driven laser at the mid-infrared wavelength around 1.8 μm generated from optical parametric amplifiers (OPA). Not only does such a short pulse approach one atomic unit in time (24 as); driven laser systems may also provide a wider tunable spectral range and better accessibility, making HHG and attosecond pulse radiation more versatile for much broader applications. With the above mentioned remarkable progresses, the field of attosecond science and technology has pushed its boundaries from atomic electron dynamics into a number of new physics fields, including HHG in solids, ultrafast electron dynamics in condensed matter and large biological molecules. The possibility to directly measure and control the electron dynamics in complex systems, which is at the basis of the fundamental processes in nature, may open new directions for atto-condensed-matter physics and atto-chemistry, with important consequences for both fundamental research and technology.
To deepen the impact of the 6th International Conference on Attosecond Physics, this special issue, “Attosecond Science and Technology,” aims to provide an overview on attosecond physics and relevant technology. The articles appearing in this issue are the fruit of the hard work of the authors, referees, and editors. We believe that the latest results appearing in this special issue will promote new progresses in attoseond science.