Periodic Reporting for period 1 - TRES-CHIC-ESt (Time-Resolved Electron Spectroscopy of a Challenging Highly Innovative Collective Excitation Study)
Okres sprawozdawczy: 2021-04-01 do 2023-03-31
The work conducted during the action entitled “Time-Resolved Electron Spectroscopy: a Challenging Highly Innovative Collective Excitation Study” (TRES-CHIC-ESt) is devoted to the investigation of a series of open scientific questions concerning the dynamics of a characteristic type of electronic interaction in solid matter exhibiting a “many-body” character; the collective excitation of the solid-state electrons leading to a plasmon resonance.
Plasmons represent a many-body response of the electronic subsystem to an external perturbation – e.g. an incident electron, photon (or ion) – inducing the polarisation of its surface or bulk. They are a coherent superposition of a small number of electron-hole pairs oscillating in the valence (conduction) band. Being a multi-electron process, plasmons are intrinsically complicated to describe and, typically they are simplified as “quasi-particles”. Albeit practical, this quasi-particle description no longer holds if the target goes beyond a free-electron gas material and if the experiments are performed on the femtosecond-timescale.
Although plasmons are known since the 70’s to play a key role in Secondary Electron Emission (SEE) only in the recent past the correlation between the energy loss process giving rise to the plasmon wake and the concomitant SEE has been disclosed. Open scientific questions concern the excitation, the build-out and the decay of a plasmon as well as the details of the phenomenon of SEE.
The combination of plasmon resonances with nanoscale structures has become a promising route in photovoltaics, magneto-plasmonics and sensoring devices. The interaction of surface plasmons with light is controlled by tailoring shape and size of nanostructures. Both plasmon resonances and the concomitant generation and emission SEs are being exploited in a whole manifold of modern technological applications. Therefore, deepening the understanding on these two correlated electronic processes, revealing their temporal evolution, is not only interesting from a fundamental point of view, but it also represents a relevant step necessary to achieve a goal-oriented tailoring of a material for the above-mentioned applications.
The overall objective of the action is to observe in real-time the dynamics of these plasmon resonances, to unveil the details of the temporal evolution of these fundamental phenomena of the solid state.
The experiments described in the TRES-CHIC-ESt project aim at providing a set of benchmark data that can help to refine and improve the currently available theoretical models, which lack a rigorous treatment of their many-body nature.
Plasmons represent a many-body response of the electronic subsystem to an external perturbation – e.g. an incident electron, photon (or ion) – inducing the polarisation of its surface or bulk. They are a coherent superposition of a small number of electron-hole pairs oscillating in the valence (conduction) band. Being a multi-electron process, plasmons are intrinsically complicated to describe and, typically they are simplified as “quasi-particles”. Albeit practical, this quasi-particle description no longer holds if the target goes beyond a free-electron gas material and if the experiments are performed on the femtosecond-timescale.
Although plasmons are known since the 70’s to play a key role in Secondary Electron Emission (SEE) only in the recent past the correlation between the energy loss process giving rise to the plasmon wake and the concomitant SEE has been disclosed. Open scientific questions concern the excitation, the build-out and the decay of a plasmon as well as the details of the phenomenon of SEE.
The combination of plasmon resonances with nanoscale structures has become a promising route in photovoltaics, magneto-plasmonics and sensoring devices. The interaction of surface plasmons with light is controlled by tailoring shape and size of nanostructures. Both plasmon resonances and the concomitant generation and emission SEs are being exploited in a whole manifold of modern technological applications. Therefore, deepening the understanding on these two correlated electronic processes, revealing their temporal evolution, is not only interesting from a fundamental point of view, but it also represents a relevant step necessary to achieve a goal-oriented tailoring of a material for the above-mentioned applications.
The overall objective of the action is to observe in real-time the dynamics of these plasmon resonances, to unveil the details of the temporal evolution of these fundamental phenomena of the solid state.
The experiments described in the TRES-CHIC-ESt project aim at providing a set of benchmark data that can help to refine and improve the currently available theoretical models, which lack a rigorous treatment of their many-body nature.
The work has been carried out in the laboratory of the Ultrafast Laser Group of the Photonics Institute at the Vienna University of Technology (TU Wien).
The first task was to design and assemble a suitable end-station for the performance of the series of Time Resolved-Photoelectron Emission Spectroscopy (TR-PES) experiments from the Al surfaces. The ER learned to use a 3D-CAD software for mechanical design to draw and plan in detail the geometry of the experiment. Together with members of the technical staff, the ER planned, designed, manufactured and implemented all components into the TRES-CHIC-ESt experiment - ranging from the extreme ultraviolet (XUV) beamline to the UHV-chamber end station.
During the first year of her fellowship, the project started to accumulate a significant time delay due to the break-down of an essential component of the Ytterbium-based laser amplifier needed for the experiments. This caused a laser-shutdown phase of about eight months. Additional postponements in the project time plan were caused by the delayed delivery of special components. Since the majority of the tasks and deliverables were strongly interdependent, the accumulated delay impacted the progress of the whole action. However, it is relevant to point out that, at present, the testing and calibration phase of the newly built XUV-beamline as well as of the UHV-end-station are near to completion and measurements foreseen by the project will be carried our within the upcoming months.
The experienced researcher (ER) constantly pursued her scientific objectives with the highest of motivation and in spite of having to solve a series of discouraging technical difficulties she persevered in her work, finding alternative solutions and embracing additional routes to overcome these contingencies. Through the fellowship, AB has received high-quality training enabling her to grow as a scientist, learning a whole new set of experimental skills in the field of Ultrafast Optics and she managed to assert herself a role as a valued group member. The ER has been constantly engaged in the realisation of her project and in parallel she has enthusiastically participated and contributed to all available activities and scientific exchanges occurring at her institute, fully integrating in the research group.
After completion of the MSCA IF, both the group leader and the institute director have entrusted AB as a successor for taking over a leadership role in another project, a so-called “Young Independent Researcher Groups” (ZK-91) funded by the Austrian Science Fund.
In this ZK-91 she is one of three principal investigators, also supervising a PhD student.
AB engaged in multiple outreach activities for the general public. In particular, she participated to a course on didactical communication of arts for interdisciplinary education at the University of Applied Arts in Vienna, where she taught basic Physics concepts focussing on the principles of the “attosecond” and of “plasmons”. This intense collaboration resulted i.a in a publication in the peer-reviewed bilingual journal. Further outreach activities were conducted at the Photonics Institute, where together with her colleagues, the ER engaged also in laboratory tours for students of Photonics, but also for university students of various university curricula.
She attended several international conferences, acquiring further knowledge on Ultrafast Optics and engaged in several collaborations. After attending the Users’ Workshop at the Extreme Light Infrastructure ELI-ALPS in Szeged, she initiated a collaboration with the experimental group of the NanoESCA end station. AB recently submitted a research proposal to their facility and is currently awaiting for the evaluation results.
In spite of all the delays caused by the contingencies listed above, the ER has profited enormously from this MSCA fellowship. Through the hard work done during the past two years, her scientific objectives are finally within reach.
The first task was to design and assemble a suitable end-station for the performance of the series of Time Resolved-Photoelectron Emission Spectroscopy (TR-PES) experiments from the Al surfaces. The ER learned to use a 3D-CAD software for mechanical design to draw and plan in detail the geometry of the experiment. Together with members of the technical staff, the ER planned, designed, manufactured and implemented all components into the TRES-CHIC-ESt experiment - ranging from the extreme ultraviolet (XUV) beamline to the UHV-chamber end station.
During the first year of her fellowship, the project started to accumulate a significant time delay due to the break-down of an essential component of the Ytterbium-based laser amplifier needed for the experiments. This caused a laser-shutdown phase of about eight months. Additional postponements in the project time plan were caused by the delayed delivery of special components. Since the majority of the tasks and deliverables were strongly interdependent, the accumulated delay impacted the progress of the whole action. However, it is relevant to point out that, at present, the testing and calibration phase of the newly built XUV-beamline as well as of the UHV-end-station are near to completion and measurements foreseen by the project will be carried our within the upcoming months.
The experienced researcher (ER) constantly pursued her scientific objectives with the highest of motivation and in spite of having to solve a series of discouraging technical difficulties she persevered in her work, finding alternative solutions and embracing additional routes to overcome these contingencies. Through the fellowship, AB has received high-quality training enabling her to grow as a scientist, learning a whole new set of experimental skills in the field of Ultrafast Optics and she managed to assert herself a role as a valued group member. The ER has been constantly engaged in the realisation of her project and in parallel she has enthusiastically participated and contributed to all available activities and scientific exchanges occurring at her institute, fully integrating in the research group.
After completion of the MSCA IF, both the group leader and the institute director have entrusted AB as a successor for taking over a leadership role in another project, a so-called “Young Independent Researcher Groups” (ZK-91) funded by the Austrian Science Fund.
In this ZK-91 she is one of three principal investigators, also supervising a PhD student.
AB engaged in multiple outreach activities for the general public. In particular, she participated to a course on didactical communication of arts for interdisciplinary education at the University of Applied Arts in Vienna, where she taught basic Physics concepts focussing on the principles of the “attosecond” and of “plasmons”. This intense collaboration resulted i.a in a publication in the peer-reviewed bilingual journal. Further outreach activities were conducted at the Photonics Institute, where together with her colleagues, the ER engaged also in laboratory tours for students of Photonics, but also for university students of various university curricula.
She attended several international conferences, acquiring further knowledge on Ultrafast Optics and engaged in several collaborations. After attending the Users’ Workshop at the Extreme Light Infrastructure ELI-ALPS in Szeged, she initiated a collaboration with the experimental group of the NanoESCA end station. AB recently submitted a research proposal to their facility and is currently awaiting for the evaluation results.
In spite of all the delays caused by the contingencies listed above, the ER has profited enormously from this MSCA fellowship. Through the hard work done during the past two years, her scientific objectives are finally within reach.
Although the progress of the action was halted by the series of technical problems listed previously, the ER is having the opportunity to carry on with her research and all inherent future achievements will be opportunely reported following the guidelines of the action.
The acquired data will be analysed and published in peer-reviewed journals as also foreseen in the original proposal. First results will be exploited to support new project proposals, that shall ensure the possibility to continue with this work in the future.
For the reasons mentioned above, unveiling details on the temporal evolution of the plasmon will potentially be of great relevance to a vast range of technological applications, and with them, this type of research can have significant impacts also from a socio-economic point of view.
The acquired data will be analysed and published in peer-reviewed journals as also foreseen in the original proposal. First results will be exploited to support new project proposals, that shall ensure the possibility to continue with this work in the future.
For the reasons mentioned above, unveiling details on the temporal evolution of the plasmon will potentially be of great relevance to a vast range of technological applications, and with them, this type of research can have significant impacts also from a socio-economic point of view.