Title: Ultrafast phenomena at the nanoscale

Speaker: Dr. Nicolò Maccaferri — Ultrafast Nanoscience, Department of Physics, Umeå University, Sweden

Where: Zoom (Meeting ID: 617 3126 3754, Passcode: 490241)

Abstract:

Ultrafast control of light-matter interactions is fundamental to mark new technological frontiers, for instance in light-driven information processing and nanoscale photochemistry [1]. In this context, we have investigated metal-dielectric nanocavities to achieve all-optical modulation of light reflectance [2], ultrafast carrier dynamics at the interface between metals and semiconductors [3] and in archetypical polaritonic systems [4]. More recently, we have focused on nanoporous metamaterials where we observed transient plasmon-induced interband transitions [5], as well as anomalous ultrafast charge and spin dynamics [6] compared to the bulk counterpart. Finally, we will show the first experimental observation of ultrafast transient grating-induced Bloch modes in hyperbolic metamaterials, pushing the boundaries of time-varying media towards optical frequencies [7].

Journal articles

1. N. Koya et al, Advances in ultrafast plasmonics. Appl. Phys. Rev. 10, 021318 (2023)
2. Kuttruff et al, Ultrafast all-optical switching enabled by epsilon-near-zero-tailored absorption in metal-insulator nanocavities. Commun. Phys. 3, 114 (2020)
3. Keller et al, Ultrafast thermionic electron injection effects on exciton formation dynamics at a van der Waals semiconductor/metal interface. ACS Photonics 9, 2683 (2022)
4. Kuttruff et al, Sub-picosecond collapse of molecular polaritons to pure molecular transition in plasmonic photoswitch-nanoantennas. Nat. Commun. 14, 3875 (2023)
5. Tapani et al, Ultrafast plasmon-induced interband transitions in nanoporous gold. Submitted (2025)
6. Tapani et al, Anomalous ultrafast charge and spin dynamics in nickel nanoporous films. Submitted (2025)
7. Tapani et al, Temporal Bloch modes induced by a plasmonic transient grating. Submitted (2025)