Colloidal semiconductor nanoplatelets exhibit quantum size effects due to their thickness of only few monolayers, together with strong optical band-edge transitions facilitated by large lateral extensions. In this article we demonstrate room temperature strong coupling of the light and heavy hole exciton transitions of CdSe nanoplatelets with the photonic modes of an open planar microcavity. Vacuum Rabi splittings of 66±1 meV and 58±1 meV are observed for the heavy and light hole excitons respectively, together with a polariton-mediated hybridisation of both transitions. By measuring the concentration of platelets in the film we compute the transition dipole moment of a nanoplatelet exciton to be μ=(575±110) D. The large oscillator strength and fluorescence quantum yield of semiconductor nanoplatelets provide a perspective towards novel photonic devices, combining polaritonic and spinoptronic effects.
@article{arxiv.1608.05294,
title = {Strong exciton-photon coupling with colloidal nanoplatelets in an open microcavity},
author = {Lucas C. Flatten and Sotirios Christodoulou and Robin K. Patel and Alexander Buccheri and David M. Coles and Benjamin P. L. Reid and Robert A. Taylor and Iwan Moreels and Jason M. Smith},
journal= {arXiv preprint arXiv:1608.05294},
year = {2016}
}