Ultrafast tunneling microscopy by optical field control of quantum currents

Informazioni relative al progetto

UpTEMPO

ID dell’accordo di sovvenzione: 819871

DOI

10.3030/819871

Progetto chiuso

Data della firma CE 23 Gennaio 2019

Data di avvio 1 Settembre 2019

Data di completamento 28 Febbraio 2025

Finanziato da

• EXCELLENT SCIENCE - European Research Council (ERC)

Costo totale

€ 1 999 509,00

Contributo UE

€ 1 999 509,00

Coordinato da

UNIVERSITE DU LUXEMBOURG
Luxembourg

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

Periodo di rendicontazione: 2024-03-01 al 2025-02-28

Sintesi del contesto e degli obiettivi generali del progetto

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.

Lavoro eseguito dall’inizio del progetto fino alla fine del periodo coperto dalla relazione e principali risultati finora ottenuti

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.

Progressi oltre lo stato dell’arte e potenziale impatto previsto (incluso l’impatto socioeconomico e le implicazioni sociali più ampie del progetto fino ad ora)

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