Room Temperature Superfluorescence from an Electron-Hole Liquid

Superfluorescence, a coherent burst of light from an excited ensemble of emitters, is a crucial quantum optical phenomenon with far-reaching implications in nanophotonics and many-body optical processes. Despite its observation in various systems, realizing superfluorescence in an electron-hole plasma (EHP) at room temperature has remained a formidable challenge, hindering the development of continuous-wave and electrically excited superfluorescence devices. Herein, we address this challenge by condensing the high-density EHP into an electron-hole liquid (EHL) at room temperature, thereby preserving quantum coherence. Using a model system of nanocrystal thin films, we demonstrate the first experimental observation of room temperature superfluorescence from an EHL. Key attributes heralding superfluorescence include a redshift of ∼94 meV from uncorrelated exciton emission, a fluence-dependent delayed growth of macroscopic coherence with abrupt radiative decay ∼1250 times faster than spontaneous emission, a distinct quadratic fluence dependence with a clear threshold, and Burnham-Chiao ringing. These findings open up exciting possibilities for developing electrically pumped colloidal nanocrystals lasers and quantum technologies operating at room temperature.