Plasmon–Exciton Strong Coupling Effects of the Chiral Hybrid Nanostructures Based on the Plexcitonic Born–Kuhn Model

Abstract

A deep understanding of the optical properties of the chiral plexcitonic systems not only adds a new dimension to the exploration of the strong plasmon−exciton interaction but also provides a new method to design chiroptical devices. We develop a plexcitonic Born−Kuhn model to explore the strong coupling dynamics of the chiral hybrid nanostructures made of cornerstacked nanorod dimers and molecules from the chiroptical perspective. As a consequence of strong interaction between plasmons and excitons, double normal mode splittings/Rabi splittings and an anti-crossing phenomenon appear in circular dichroism (CD) spectroscopy. The character of dual plexciton (symmetric and anti-symmetric plexciton) and associated chiroptical properties have been demonstrated. The interplay between mirror symmetry breaking and plasmon−plasmon/plasmon−exciton interaction leads to an optimal configuration with the maximal chiroptical response. Moreover, chirality (of incident light) selective excitation of plexcitonic modes has been achieved by structural design. Finally, we verify our theory experimentally by synthesizing chiral plasmonic nanodimers and coating these structures with Jaggregate dye molecules.

Triple Plexcitonic Nonreciprocity of Magnetochiral Plexcitons

“…It is worth mentioning that their difference is mainly reflected in the change of the energy branches of the dual plexcitonic state SP± and AP± (see SI, Supporting figures E). The SP±/AP± gives a splitting with 143.6/141.7 meV in the absence of an external magnetic field, satisfying the strong coupling criterion of dual plexcitons . Therefore, the magnetochiral plexcitons in Mch hybrid metamaterials reach the strong coupling regime and satisfy the necessary physical conditions for achieving nonreciprocity.…”

“…The SP±/AP± gives a splitting with 143.6/141.7 meV in the absence of an external magnetic field, satisfying the strong coupling criterion of dual plexcitons. 61 Therefore, the magnetochiral plexcitons in Mch hybrid metamaterials reach the strong coupling regime and satisfy the necessary physical conditions for achieving nonreciprocity.…”

Tuning the Plexcitonic Optical Chirality Using Discrete Structurally Chiral Plasmonic Nanoparticles

“…Interestingly, Rabi splitting and anticrossing behavior were observed in not only extinction but also circular dichroism (CD) spectra, which can be attributed to strong plasmon–exciton coupling . On the contrary, by employing chiral plasmonic nanodimers instead of achiral plasmonic NPs, interesting Rabi splitting in CD spectra was observed for the chiral plexcitonic systems with dual plexciton character. , However, controlling the chiral hybrid architecture and plexcitonic optical chirality of the chiral plexcitonic systems remains a challenge.…”