Ultrafast tunneling microscopy by optical field control of quantum currents

Projektinformationen

UpTEMPO

ID Finanzhilfevereinbarung: 819871

DOI

10.3030/819871

Projekt abgeschlossen

EK-Unterschriftsdatum 23 Januar 2019

Startdatum 1 September 2019

Enddatum 28 Februar 2025

Finanziert unter

• EXCELLENT SCIENCE - European Research Council (ERC)

Gesamtkosten

€ 1 999 509,00

EU-Beitrag

€ 1 999 509,00

Koordiniert durch

UNIVERSITE DU LUXEMBOURG
Luxembourg

Periodic Reporting for period 4 - UpTEMPO (Ultrafast tunneling microscopy by optical field control of quantum currents)

Berichtszeitraum: 2024-03-01 bis 2025-02-28

Zusammenfassung vom Kontext und den Gesamtzielen des Projekts

In this project, we implemented a scanning tunnelling microscope (STM) fully driven by the electric field of single cycle light pulses. In this way, we aim at measuring ultrafast phenomena occurring on a timescale of few femtoseconds with a spatial resolution down to individual atoms.
This goal was achieved by generating light pulses that consist in a single cycle of the electromagnetic oscillation. These transients can be focused on an STM tip to act as the source of the bias that drives the current through the sample under investigation with atomic resolution. The ultrafast STM can then be used in combination with other ultrashort pulses employed to excite the samples to probe and derive movies of the charge motions in molecules and nanostructures. The final goal that will be pursued beyond the dureation of funding is to better understand and harness fundamental processes like charge localization and germination with applications that range from sensing to photovoltaics.

Arbeit, die ab Beginn des Projekts bis zum Ende des durch den Bericht erfassten Berichtszeitraums geleistet wurde, und die wichtigsten bis dahin erzielten Ergebnisse

The novel technique developed in this project, requires the setup of a suitable laser source and of a scanning tunnelling microscope (STM) capable of being coupled with the ultrashort light pulses. These tasks were successfully completed (main publications: Nature Physics 16 (3), 341-345 and Nanophotonics 13 (15), 2803-2809 with several other technological papers and conference proceedings). We are being able to generate ultrabroadband spectra supporting durations down to a single cycle and the STM has been tested in combination with an optical pulse train. The two subsystems have been combined and we are able to generate sub-optical-cycle currents in the in the STM. The STM has also been equipped to operate at cryogenic temperature (a paper is under preparation). This approach will improve the demodulation of the signal is as the last step before proceeding to the final goal of measuring ultrafast dynamics with atomic resolution.
The task of performing pump-probe experiments has not been possible given the extreme difficulties in the optimization of the system. However, there are no fundamental limitations and the efforts will continue.

Fortschritte, die über den aktuellen Stand der Technik hinausgehen und voraussichtliche potenzielle Auswirkungen (einschließlich der bis dato erzielten sozioökonomischen Auswirkungen und weiter gefassten gesellschaftlichen Auswirkungen des Projekts)

We developed an innovative laser platform for the generation of single cycle pulses and achieved the all-optical drive of a scanning tunnelling microscope at near-IR frequencies and at low temperature.

A single cycle light pulse induces Electron transport