2023/12/26 by Kai-Fu Wong, Wong, Kai-Fu, Weiwei Li +23 · 1 citation
Engineering · Physics and Astronomy · #FOS: Physical sciences #Laser-Matter Interactions and Applications #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Optics (physics.optics) #Spectroscopy and Quantum Chemical Studies #Terahertz technology and applications
paper · pdf · doi:10.48550/arxiv.2312.16121
openalex publication_date 2023/12/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
The collective response of metal nanostructures to optical excitation leads to localized plasmon generation with nanoscale field confinement driving applications in e.g. quantum optics, optoelectronics, and nanophotonics, where a bottleneck is the ultrafast loss of coherence by different damping channels. The present understanding is built-up on indirect measurements dictated by the extreme timescales involved. Here, we introduce a straightforward field sampling method that allows to measure the plasmonic field of arbitrary nanostructures in the most relevant petahertz regime. We compare experimental data for colloidal nanoparticles to finite-difference-time-domain calculations, which show that the dephasing of the plasmonic excitation can be resolved with sub-cycle resolution. Furthermore, we observe a substantial reshaping of the spectral phase of the few-cycle pulse induced by this collective excitation and we demonstrate ad-hoc pulse shaping by tailoring the plasmonic sample. The results pave the way towards both a fundamental understanding of ultrafast energy transformation in nanosystems and practical applications of nanostructures in extreme scale spatio-temporal control of light.