Time-Resolved Spectroscopy of Strong-Field-Driven Solids

Project Information

TReSFiDS

Grant agreement ID: 886092

DOI

10.3030/886092

Project closed

EC signature date 4 March 2020

Start date 1 September 2021

End date 31 August 2023

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 207 312,00

EU contribution

€ 207 312,00

Coordinated by

AARHUS UNIVERSITET
Denmark

Periodic Reporting for period 1 - TReSFiDS (Time-Resolved Spectroscopy of Strong-Field-Driven Solids)

Reporting period: 2021-09-01 to 2023-08-31

Summary of the context and overall objectives of the project

Intense, ultrashort laser pulses are currently being used to manipulate the ultrafast motion of the electrons in solids on their natural, sub-femtosecond timescales. This can have wide technological and societal implications. It can lead to ultrafast, petahertz optoelectronic devices able to overcome the speed limits of contemporary digital electronics. It can also enable novel, more compact sources of high-frequency radiation, based on high-order harmonic generation in solids.

The origin of these strong-field processes and their dependence on the properties of the solid had not been fully understood and systematically investigated. The project has developed the numerical and analytical methods required to simulate and understand the processes involved in the strong-field excitation of solids. I have investigated the dependence of the strong-field dynamics on key properties of the solid, and I have identified how they are imprinted in the spectral features of observable absorption spectra. These novel signatures can guide and trigger near-future experiments in the time-resolved spectroscopy of condensed-matter systems.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

I have developed and employed codes based on time-dependent density functional theory (TDDFT) and developed supporting analytical methods in order to describe the interaction between a linear chain of atoms and short laser pulses. I have thereby described the evolution of electron–hole pairs between several valence and conduction bands excited by intense laser pulses in different types of solids, as a function of key parameters such as the number of atoms, the lattice constant, and the type of atoms. For each case, I have simulated corresponding time-resolved absorption spectra resulting from the interaction of the sample and a suitably delayed attosecond probe pulse. The simulated time-resolved absorption spectra have highlighted key signatures encoding the strong-field dynamics in the solid and their dependence on the properties of the sample.

In order to ensure the immediate exploitation and experimental verification of our results, I have discussed the results of this project with theory and experimental colleagues in group seminars and at conferences. The results will also be submitted for publication in peer-reviewed journals. To ensure dissemination of the results of the project to a broad audience including non-specialists in the field, I have also participated in outreach events such as the Festival of Research 2022 on Time at Aarhus University.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The techniques developed in this project have provided a new understanding of how key properties of a solid-state system influence its electronic response to short intense laser pulses. Furthermore, by relating these strong-field dynamics to signatures in currently accessible time-resolved absorption spectra, we have shown how ultrafast electron dynamics in solids can be observed with existing technology. This represents a crucial step towards the design of novel systems and materials for ultrafast spectroscopy and petahertz optoelectronic applications.

The two-way transfer of knowledge between me and the hosting group has provided me with transferable skills and technical knowledge from different research areas, both in ultrafast science and solid-state physics. Furthermore, working at the project has opened new collaboration opportunities and given me access to different research communities.

In order to communicate the objectives and results of the project to a broad audience, and to introduce the general public to our group’s research on ultrafast science and spectroscopy, I have taken part in outreach events organized by Aarhus University. I have participated in the Festival of Research 2022 at Aarhus University, which focused on the topic of time and was attended by about 1,000 people. For our stand at the Festival of Research, I produced posters and movies and organized activities in order to present in an accessible way our work on ultrafast electron dynamics on the attosecond timescale.

Strong-field excitation of the solid and time-resolved absorption setup