Cavity-modified spontaneous-emission rates in liquid microdroplets

Abstract
We observe significant lifetime modification (both reduction and lengthening) of 610–620-nm light spontaneously emitted by chelated europium ions in 10-μm-diam dimethylformamide-alcohol solution droplets. The enhancement or inhibition of the Einstein A coefficient over the familiar free-space value is direct evidence of cavity quantum-electrodynamic effects taking place in microdroplets.