Xiong, X., Lai, Y., Clarke, D., Kongsuwan, N., Dong, Z., Bai, P., Png, C. E., Wu, L., & Hess, O. (2022). Control of Plexcitonic Strong Coupling via Substrate‐Mediated Hotspot Nanoengineering. Advanced Optical Materials, 10(17), 2200557. Portico. https://doi.org/10.1002/adom.202200557
Plexcitonic strong coupling has ushered in an era of room-temperature quantum electrodynamics at the nanoscale. Realizing its potential applications from single-molecule spectroscopy to room-temperature quantum technologies on an industrial level requires scalable and mass-producible plasmonic cavities that provide ease of access and control for quantum emitters. Here, a strategy for multidimensional hotspot engineering is proposed via a rational selection of substrates, which facilitates elevation of a gold bowtie nanocavity hotspot to the top of the device and provides a field enhancement of ≈482 (a 1.6-fold increase compared to a conventional bowtie-on-glass cavity at the bottom of the nanogap). The formation mechanism for these antenna modes is discussed from the perspective of charge carrier motion; and their advantages, particularly in view of their dominantly in-plane polarized near-fields, are further elaborated in a spatiotemporal study of plexcitonic strong coupling, which reveals ultrafast quantum dynamics and potential for applications related to 2D materials whose excitonic dipoles are typically oriented in-plane. The conceptual discovery of this substrate-enabled hotspot nanoengineering could readily be extended to tailor hotspots in other plasmonic platforms, and may inspire a plethora of novel research directions from plasmon-enhanced spectroscopy and sensing to the design of quantum logic gates and quantum metasurfaces.
Attribution 4.0 International (CC BY 4.0)
This research / project is supported by the A*STAR - Strategic Program
Grant Reference no. : C210917001
This research / project is supported by the Singapore University of Technology and Design - Start-Up Research Grant
Grant Reference no. : SRG SMT 2021 169