by Dr. Kishan S. Menghrajani, Monash University, Australia

Abstract: 

Open cavities have been put forward as a convenient platform with which to undertake molecular strong coupling. Whilst a number of demonstrations of Rabi-splitting in open cavities have been reported by monitoring reflectivity and/or transmission, it remains unclear whether such structures drive a molecular resonance into the strong coupling regime. Here we explore a more stringent monitor of strong coupling, the modification of photoluminescence. We examine the emission from a range of dye-doped open, half and full optical microcavities.

For each configuration an analysis of the reflectivity data indicates the presence of strong coupling. We find that our open and half cavities show only minor modifications of the photoluminescence spectrum. For the full-cavity, for which the dielectric layer is bound both above and below by a metallic mirror, we find very significant modification, the photoluminescence clearly tracking the lower polariton. This technique may be of relevance in designing strong coupling resonators for chemistry and materials science investigations to probe a fascinating aspect of molecular strong coupling, a new field that spans physics, chemistry, and materials science and that promises to add cavity quantum electrodynamics to the chemistry/materials toolkit.