Forthcoming Events

16.12.2021 - 21.12.2021, Honolulu, Hawaii, USA
01.06.2022 - 30.06.2022, Grindelwald, Switzerland
27.06.2022 - 29.06.2022, University College London, UK


NCCR MUST at Scientifica 2021- Lightning, organic solar cells, and virtual molecules
#NCCRWomen- NCCR MUST celebrates 50 years women’s right to vote in Switzerland
Kick-Off dynaMENT Mentoring for Women in Natural Sciences- with Ursula Keller as plenary speaker
Four new scientific highlights- by MUST PIs Chergui / Milne / Beaud / Staub, by Wolf / Röthlisberger, by Wörner, and Keller
Photon Science Roadmap- for Research Infrastructures 2025-2028 by the Swiss Photon Community
Proof of concept ERC Grant for Ursula Keller Dual-comb laser driven terahertz spectrometer for industrial sensing (DC-THz)
Majed Chergui - elected to the European Academy of Sciences
Ruth Signorell - elected to the European Academy of Sciences
Farewell and Welcome!Chris Milne leaves for the European XFEL, Camila Bacellar takes over
SY-GAIA expedition - measures aerosols in the North-Atlantic

Complete characterization of sub-Coulomb-barrier tunnelling with phase-of-phase attoclock

July 14, 2021

(Published in Nature Photonics)
Laser-induced electron tunnelling—which triggers a broad range of ultrafast phenomena such as the generation of attosecond light pulses, photoelectron diffraction and holography—has laid the foundation for strong-field physics and attosecond science. Using the attoclock constructed by single-colour elliptically polarized laser fields, previous experiments have measured the tunnelling rates, exit positions, exit velocities and delay times for some specific electron trajectories, which are mostly created at the field peak instant, that is, when the laser electric field and the formed potential barrier are stationary in terms of the derivative versus time. From the view of wave-particle dualism, the electron phase under a classically forbidden, tunnelling barrier has not been measured, which is at the heart of quantum tunnelling physics.
The authors present a robust measurement of tunnelling dynamics including the electron sub-barrier phase and amplitude. They combine the attoclock technique with two-colour phase-of-phase (POP) spectroscopy to accurately calibrate the angular streaking relation and to probe the non-stationary tunnelling dynamics by manipulating a rapidly changing potential barrier. This POP attoclock directly links the measured phase of the two-colour relative phase with the ionization instant for the photoelectron with any final momentum on the detector, allowing the researchers to reconstruct the imaginary tunnelling time and the accumulated phase under the barrier. The POP attoclock provides a general time-resolved approach to accessing the underlying quantum dynamics in intense light–matter interactions.

Fig. 2: Experimental results of the POP attoclock. a,b, Measured POP (a) and contrast (b) spectra for krypton atoms in the POP attoclock configuration. c, The cuts of ΦPOP along energies of 4 eV (left), 8 eV (middle) and 16 eV (right). On the right vertical coordinate the phase of the phase is transformed to the ionization instant using ΦPOP = ωt.
Reference: Han, M., P. Ge, J. Wang, Z. Guo, Y. Fang, X. Ma, X. Yu, Y. Deng, H. J. Wörner, Q. Gong and Y. Liu (2021). "Complete characterization of sub-Coulomb-barrier tunnelling with phase-of-phase attoclock." Nature Photon. (10.1038/s41566-021-00842-7).

NCCR MUST Office : ETHZ IQE/ULP-HPT H3 | Auguste-Piccard-Hof 1 | 8093 Zurich | E-Mail | +41 44 633 36 02
The National Centres of Competence in Research (NCCR) are a research instrument of the Swiss National Science Foundation