Physical and Analytical Chemistry Seminar
Lecturer: Prof. Gilad Haran
Location: Faculty Seminar Room
Nanostructures in which individual plasmon modes strongly interact and show distinct collective behavior are sometimes called Plasmonic Molecules (PMs) (1). Interactions between such collective modes and external perturbations may lead to phenomena analogous to those found in molecular systems. The analogy paves the way to the application of concepts developed in Chemical Physics to PMs. Two such applications will be described in the lecture.
In the first part we will discuss how group theory can help understanding the spectroscopy of PMs self-assembled from three silver nanoparticles (2). An equilateral triangular PM has the highest symmetry. Breaking this symmetry lifts the degeneracy of the plasmon modes. This may affect the interaction of a PM with molecules, leading to significant modulation of the polarization of Raman scattering from these molecules (3), due to interference between plasmonic modes (4), and to the surprising emission of circularly polarized light.
In the second part we will show how the interaction between a dimeric PM with a single quantum emitter can be pushed into the so-called Strong Coupling Regime, which can be useful for applications in quantum optics and communication (5). Indeed, we observed vacuum Rabi splitting, a manifestation of strong coupling, using PM dimers made in the form of nanofabricated bowties and loaded with semiconductor quantum dots. Both scattering and photluminescence spectra showed Rabi splitting, providing strong support for the attainment of the strong coupling regime in these nanometric devices.
1. Haran G & Chuntonov L (2018) Artificial Plasmonic Molecules and Their Interaction with Real Molecules. Chem Rev.
2. Chuntonov L & Haran G (2011) Trimeric plasmonic molecules: the role of symmetry. Nano Lett 11(6):2440-2445.
3. Shegai T, et al. (2008) Managing light polarization via plasmon-molecule interactions within an asymmetric metal nanoparticle trimer. P Natl Acad Sci USA 105(43):16448-16453.
4. Chuntonov L & Haran G (2013) Maximal Raman optical activity in hybrid single molecule-plasmonic nanostructures with multiple dipolar resonances. Nano Lett 13(3):1285-1290.
5. Santhosh K, Bitton O, Chuntonov L, & Haran G (2016) Vacuum Rabi splitting in a plasmonic cavity at the single quantum emitter limit. Nature communications 7:ncomms11823.