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Nature photonics 13(2), 91 - 95 (2019). doi:10.1038/s41566-018-0308-z, A key challenge in attosecond science is the temporal characterization of attosecond pulses that are essential for understanding the evolution of electronic wavefunctions in atoms, molecules and solids. Current characterization methods, based on nonlinear light–matter interactions, are limited in terms of stability and waveform complexity. Here, we experimentally demonstrate a conceptually new linear and all-optical pulse characterization method, inspired by double-blind holography. Holography is realized by measuring the extreme ultraviolet (XUV) spectra of two unknown attosecond signals and their interference. Assuming a finite pulse duration constraint, we reconstruct the missing spectral phases and characterize the unknown signals in both isolated pulse and double pulse scenarios. This method can be implemented in a wide range of experimental realizations, enabling the study of complex electron dynamics via a single-shot and linear measurement., Published by Nature Publ. Group, London [u.a.]

Nature photonics 11(6), 383 - 389 (2017). doi:10.1038/nphoton.2017.73, An electrical pulse E(t) is defined completely by its time-dependent amplitude and polarization direction. For opticalpulses the manipulation and characterization of the light polarization state is fundamental because of its relevance inseveral scientific and technologicalfields. In this work, we demonstrate the complete temporal reconstruction of theelectricfield of few-cycle pulses with a complex time-dependent polarization. Our experimental approach is based onextreme ultraviolet interferometry with isolated attosecond pulses and on the demonstration that the motion of anattosecond electron wave packet is sensitive to perturbingfields only along the direction of its motion. By exploiting thesensitivity of interferometric techniques and by controlling the emission and acceleration direction of the wave packet,pulses with energies as low as a few hundreds of nanojoules can be reconstructed. Our approach reveals the possibility tocharacterize completely the electricfield of the pulses typically used in visible pump–probe spectroscopy., Published by Nature Publ. Group, London [u.a.]

Nature Photon. 11, 383–389 (2017); published online 29 May 2017; corrected after print 29 June 2017. In the version of this Article originally published, the following sentences were missing from the Acknowledgements: “Financial support by the Alexander von Humboldt Foundation (Project Tirinto) and the Italian Ministry of Research (project FIRB no.

The development of attosecond technology is one of the most significant achievements in the field of ultrafast optics over the past decade. Since the first experimental demonstration of attosecond pulses just ten years ago, novel techniques have been introduced for the generation, characterization and application of subfemtosecond pulses. The development of attosecond tools is continuously triggering the introduction of new spectroscopic and measurement methods, which will offer the opportunity to investigate unexplored research areas with unprecedented time resolution. The wealth of ultrafast processes, which can be investigated by taking advantage of attosecond temporal resolution, can be greatly extended by the development of high-intensity attosecond sources. This Review covers a selection of recent advances in the field of attosecond technology, with particular attention being given to the generation and application of high-energy attosecond pulses.

The applications of isolated attosecond pulses reported to date, which have demonstrated the great potential of attosecond technology in the investigation of ultrafast electronic processes, have been limited by the low photon flux of the available attosecond sources. We report on the generation of isolated sub-160-as pulses (at a photon energy of similar to 30 eV) with a pulse energy, on target, of a few nanojoules. The efficient generation of isolated attosecond pulses in noble gases is produced by 5-fs driving pulses with controlled electric field and peak intensity beyond the gas saturation intensity. The availability of attosecond sources with high peak intensities has potential in opening new avenues for attosecond-pump/attosecond-probe studies of electronic processes in atomic and molecular physics, with interesting prospects in the field of coherent control of electronic motion in complex systems in the attosecond temporal regime.

Surface plasmons undergo ultrafast dynamics on the attosecond timescale. Probing these ultrabrief effects is notoriously difficult, but a new microscope could pave the way towards an understanding of these fields and, ultimately, control of them.