IOQ-Kolloquium / Dr. Omer Kneller (Uni Regensburg)

Attosecond science has revolutionized the ability to capture extremely fast phenomena in nature, opening a window into a new temporal regime, in which electron dynamics are observed on their natural time scale. Attosecond metrology relies on the ability to produce optical pulses, having attosecond duration, where the electronic dynamics are imprinted in the spectral intensity, phase and polarization state of such attosecond pulses. However, the optical measurement resolves only the spectral intensity while the phase and polarization information are lost, preventing a direct access to the full information encoded in the attosecond signal.

In my talk, I will describe how we extend one of the most fundamental optical schemes, interferometry, to the attosecond timescale. Our state-of-the-art all-optical attosecond interferometry scheme reveals some of the fastest phenomena in nature, such as the moment at which an electron is photoionized or the evolution of an electronic wavefunction under the tunneling barrier, as it propagates in a classically forbidden region. Our recent development of attosecond transient interferometry enables us to decouple and directly follow the temporal evolution of individual quantum paths induced in a light-driven system. Finally, I will present an outlook of how such notions allow to engineer excitonic states in atomically thin semiconductors, using intense phase-stable carrier waves of light in the multi-THz range.

References:

1. D. Azoury, O. Kneller et al., Nature Photonics 13, 54 (2019).

2. D. Azoury*, O. Kneller* et al., Nature Photonics 13, 198 (2019).

3. O. Kneller, D. Azoury et al., Nature Photonics 16, 304 (2022).

4. O. Kneller*, C. Mor*, N. Klimkin* et al., Nature Photonics 19, 134–141 (2025).

5. O. Kneller, T. Witting et al., under review, (2025). Preprint: https://doi.org/10.21203/rs.3.rs-6041019/v1

Bio:

Omer completed his BSc in physics at the Hebrew University of Jerusalem and then joined Prof. Nirit Dudovich’s lab at the Weizmann institute of science, for his MSc and PhD research in attosecond science. He is currently a postdoctoral fellow with Prof. Rupert Huber at the University of Regensburg, studying Lightwave electronics.