Light-driven phenomena in plasmonic nanocavities

Our aim is to study light-induced phenomena in plasmonic nanocavities where light is confined to subwavelength mode volumes by localized surface plasmon resonances. We fabricated nanoparticle on mirror (NPoM) nanocavities and studied the effect of the self-assembled monolayer on the optical properties of the NPoM structures, finding that an ordered and well-organized monolayer of molecules is more susceptible to permanent light-induced changes compared to a disorganized one [1], Fig 1.

In parallel, we investigated the phenomenon of photoluminescence blinking from nano-cavities.

We found evidence of laser-induced formation of nanoscale domains and quantum confined emitters, which lead to random changes in the measured photoluminescence intensity under green laser excitation [2], Fig 2. These studies show that light can induce changes at the nanoscale, the delicate effects of which are detectable in the far-field due to the nano-antenna effect.

In the future, we plan to make further refine our understanding of photoluminescence and Raman blinking, including the emergence of single-molecule Raman signals. Moving our nanofabrication capabilities further, we plan to work towards synthesizing hybrid nanophotonic devices, integrating metallic nano-clusters as well as 2D heterostructures within the NPoM architecture.

PhD students: Aqeel Ahmed, Sachin Verlekar

Postdoc: Wen Chen

Collaboration:    Prof. Maggie Lingenfelder, EPFL;

Prof. Giulia Tagliabue, EPFL

Prof. Guillermo Acuna, Univ. of Fribourg, Switzerland

                              Prof. Franceso Stellacci, EPFL


[1] A. Ahmed et al., ACS Photonics (2021)

[2] W. Chen et al., Nature Comm. (2021)

Funding:  ERC Consolidator Grant QTONE; Horizon 2020 FET-Open THOR


Fig. 1: Effect of molecular monolayer morphology on plasmonic resonance and nanocavity stability [1]
Fig. 2: Artistic view of plasmonic blinking due to light-driven movement of gold atoms inside nanocavities [2]