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Molecular Electron Dynamics investigated by IntensE Fields and Attosecond Pulses

Periodic Reporting for period 2 - MEDEA (Molecular Electron Dynamics investigated by IntensE Fields and Attosecond Pulses)

Reporting period: 2017-01-01 to 2018-12-31

Ultrafast multielectronic processes occurring on the femtosecond and attosecond timescale is fundamental in determining the behaviour of the dynamics in molecules and clusters. The understanding of these phenomena might offer new perspectives on processes occurring on “slower” timescales, such as bond-breaking in complex molecules and Coulomb explosion in charged clusters.The aim of MEDEA was to create a network where Early Stage Resechears (ESRs) received an interdisciplinary and intersectoral comprehensive research training in one of the major field of Photonics (attosecond science) that was contributed by leading universities and research centers, and by key-player companies in the development and commercialization of state-of-the-art ultrafast laser sources and detection systems.
The control of the electronic motion on this unprecedented time scale could lead to design of novel electronic devices for the processing of information at a much higher speed, than the one achievable today. In this perspectives, the experiments performed within the network could shed new light on the feasibility of devices based on the direct control of electronic wave packet using ultrashort femtosecond laser pulses.
The main objectives were to:
1) advance attosecond and femtosecond XUV spectroscopy by combining in-depth investigation of fundamental electronic processes in simple systems with experiments in complex molecules with the goal of elucidating novel electron dynamics with potential impact in chemistry, surface science, and biology
2) demonstrate the feasibility of nonlinear attosecond XUV spectroscopy on the few-femtosecond and sub-femtosecond timescale
3) obtain benchmarks for the validation of attosecond tools and femtosecond XUV pulses for the time-resolved imaging of electron and nuclear dynamics in molecules
4) contribute to the development of new technological solutions that will increase the competiveness of the industrial partners of the network
5) train a group of ESRs and contribute to their career prospects by providing them with scientific expertise in complementary research fields, knowledge in technology and innovation management, and special training in communication and outreach skills
6) increase the interest of young students in the network’s core research field (Photonics)
Novel laser sources were developed by the industrial partners of MEDEA. Such sources could become products on the market in the near future. The investigation of electronic dynamics in small molecules took advantage of the high-repetition rate source available now through the network. Similarly several groups achieved the extreme ultraviolet intensities required for the observation of nonlinear effects, making the available nonlinear spectroscopic tool also using table-top sources. Large collaboration at Free Electron Lasers have reported unique results, including the first coherent control experiment in the extreme ultraviolet region. ESRs strongly benefited from the variety of experimental setups realized.
WP1 Attosecond XUV-IR spectroscopy
Several groups conducted experiments based on the investigation of ultrafast dynamics in molecules and clusters excited by isolated attosecond pulses or attosecond pulse trains. Some results were of primary importance and were published in high-impact journal (V. Gruson et al. Science 354, 734-738 (2016)).
WP2 Non-linear XUV spectroscopy
The network obtained very important scientific results in the generation and application of intense XUV pulses, using large scale facilities such as Free Electron Lasers, as well as implementing table-top lasers in combination with long-focusing attosecond beamlines. In particular, in a large collaboration within the MEDEA network (including POLIMI, MPIK, FREIB and ELETTRA), the first experiment on coherent control in the extreme ultraviolet region. The experiment represents a milestones because it opens new possibilities for the development of time-resolved investigations using multi-color intense XUV fields. The results were published in Nature Photonics.
WP3 HHG and ultrafast electron imaging
Several groups of the network conducted theoretical studies for disentangling the structural and dynamical response of molecules in the high-order harmonic generation process. In particular, in the last period of the network, the attention was focused on the investigation of chiral molecules, and on the possibility to observe and describe their response to intense field, depending on the specific enantionmers.
ESRs released several publications also in high-impact journals including Nature and Nature Communications. Additional high-impact publications are expected in the upcoming months as a result.
WP4 Training
The training plan was completely fullfilled. 3 schools were organized, Webinars and Joint Journal Clubs (JJC) were held on a monthly basis and training Toolkits were prepared. A one-day workshop on data acquisition and valve sources and one on novel laser sources were organized by the network.
WP5 Outreach and dissemination
The communication included the MEDEA Webpage, Videos on a dedicated Youtube channel and a LinkedIn group. ESRs introduced and distributed Photonics Explorer Kits in several European secondary schools, and participated to events such the European Researchers' Night and the International Day of Light.
WP6 Management
The Coordinator led the implementation of all the planned actions, regularly took into account gender issues and supported the recruitment process.
"The network realized two scientific achievements:
1) MBI demonstrated the control of extreme-ultraviolet by refractive optics induced in dense gas-jet. These results open new possibilities in the control and steering of extreme ultraviolet radiation and could eventually lead to the design of new ""optical"" element for this spectral range. The results were published in a high-impact journal (Nature 564, pages91–94 (2018)).
2) AMPL demonstrated novel sources delivering carrier-envelope-phase stable laser pulses. Due to robustness of these new developments sources offering the control of the electric field of femtosecond pulses could be available also to non-specialist, thus potentially widening the range of applications of controlled femtosecond waveforms.
The innovative training activities strongly shaped the education of ESRs. The network-wide training activities provided scientific knowledge, as well as Open Science, Ethics in Research, Communication and Soft Skills (focused in the schools). Webinars and JJC contributed to the exchange of knowledge and experience. Individual training was tailored for each ESR specific career development. ESRs were trained in one of the most active research fields in Europe, which combines experimental and theoretical aspects of molecular and optical physics. Several ESRs, during their secondments, received a hands-on training in laser, optical and vacuum technologies that will open career and employment perspectives both in the academic world and in the private sector. Consequently, 4 ESRs are now employed in HEI, 1 in a NRC and 1 in a Large Company. MEDEA contributed to Open Science with 35 publications in open access co-authored by ESRs and 39 by PIs. Moreover, 21 videos were realized and made available to other MSCA networks and in general to the scientific community. ESRs implemented different outreach activities reaching 33 schools, 2097 students and 64 teachers."
Artistic representation of the coherent control of the electronic wave packet emission