MQT 2022

Plasmonic Cavities; Strong Coupling And Beyond

Gilad Haran Department of Chemical and Biological Physics, Weizmann Institute of Science

at  14:00for  40min

Plasmonic structures concentrate electromagnetic fields to deep sub-diffraction volumes. We will first discuss how this nanofocusing can strongly couple plasmonic cavities and individual quantum emitters. In particular, we present our studies of colloidal quantum dots within silver bowtie structures. Light scattering spectra of individual devices clearly showed a dip indicative of vacuum Rabi splitting even in the presence of a single quantum dot (1). We further found that electron energy-loss spectroscopy (EELS) within the electron microscope can probe this coupling with a nanometric spatial resolution (2). This allowed us to demonstrate Rabi splitting of dark modes that do not couple radiatively to the far field. Photoluminescence measurements revealed the non-classical nature of emission from coupled quantum dots, and demonstrated how the interaction of emitters with the cavity alters pathways of excited-state relaxation quite dramatically (3). Finally, unpublished studies (4) on giant electrochemical tuning of the resonances of plasmonic cavities will be presented- we hypothesize that differential charging is responsible for these surprising results.

  1. K. Santhosh, O. Bitton, L. Chuntonov, G. Haran, Vacuum Rabi splitting in a plasmonic cavity at the single quantum emitter limit. Nature communications 7, ncomms11823 (2016).

  2. O. Bitton, S. N. Gupta, L. Houben, M. Kvapil, V. Krapek, T. Sikola, Vacuum Rabi splitting of a dark plasmonic cavity mode revealed by fast electrons. ArXiv 1907.10299 (2019).

  3. S. N. Gupta, O. Bitton, T. Neuman, R. Esteban, L. Chuntonov, J. Aizpurua, G. Haran, Complex plasmon-exciton dynamics revealed through quantum dot light emission in a nanocavity. Nature communications 12 (2021).

  4. A. Vaskevich, A. Basu, L. Chuntonov, I. Ashiri-Kaplan, G. Haran, Unpublished (2022).

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Figure 1.: Probing strong coupling in plasmonic cavities. (A) Scattering spectra of plasmonic bowties with QDs inserted in their gaps. Top- two QDs. Bottom- three QDs. The spectra show