Dresden 2026 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 27: Plasmonics and nanooptics: Light-matter interaction, spectroscopy – Poster
O 27.2: Poster
Montag, 9. März 2026, 18:00–20:00, P2
Distinct Multiphoton Orders in Photoelectron Spectra of Individual Silver Nanoparticles — Waqas Pervez1, •Frithjof Harmsen1, Kevin Oldenburg2, Moha Naeimi1, Sylvia Speller1, and Ingo Barke1 — 1Institute of Physics, University of Rostock, Germany — 2Department of Life, Light & Matter, University of Rostock, Germany
We investigate how the multiphoton photoemission process of individual metal clusters deposited on a non-metallic substrate is affected by the particle shape and its local environment. Here we present photoelectron spectra acquired by time-of-flight spectroscopy using a photoemission electron microscope (PEEM). Size-selected particles produced in a magnetron cluster source are deposited in-situ onto silicon substrates. The cluster source can produce single particles as well as agglomerates with characteristic plasmon modes [1], as revealed by transmission electron microscopy (TEM). Photoelectron spectra are obtained using illumination by a femtosecond laser at wavelengths around 800 nm, where at least 3 photons are required to overcome the work function. In addition, we observe well-separated above-threshold processes (ATP / ATI) of 4th order and up to 7th order for agglomerates. No noticeable resonances are observed across the spectral range, in contrast to illumination around 400 nm [2], i.e., at the plasmon energy. Mechanisms are discussed in view of symmetry properties and dipole selection rules.
[1] K. Oldenburg et al., Phys. Rev. Research 7, 023267 (2025)
[2] K. Oldenburg et al., J. Phys. Chem. C 123, 1379 (2019)
Keywords: Nanoparticles; PEEM; Plasmons; Photoelectron spectroscopy; clusters