Room temperature plexciton photoluminescence of a single quantum dot in the strong coupling regime

By: Kyoung-Duck Park, Molly A. May, Haixu Leng, Jiarong Wang, Jaron A. Kropp, Theodosia Gougousi, Matthew Pelton, Markus B. Raschke

Submitted (2018)

Optical cavities can enhance and control the light-matter interaction by modifying the local electromagnetic environment of a quantum emitter. Manipulating this interaction in the non-perturbative strong couping regime opens new pathways from opto-electronic and chemical sensing to quantum information science, where it provides an attractive platform for photon entanglement and quantum state manipulation. However, large cavity mode volumes have prevented strong coupling between dielectric cavities and single emitters under ambient conditions.

We achieve room temperature strong light-matter interaction of a single quantum dot coupled to a plasmonic antenna-tip nano-cavity in a sub-nm cavity with a mode volume as small as 6 nm^3. In this strongly coupled hybrid state, we observe plexciton photoluminescence with mode splitting up to 156 meV, exceeding the cavity loss rate by >20%. In addition, by tuning the cavity gap with sub-nm precision, we reversibly control the coupling strength across the strong coupling transition. Our approach enables a new regime of nano-cavity quantum electrodynamics with manipulation of the nanoscale quantum light-matter interaction of single emitters at room temperature.