Single-photon nonlinearity at room temperature

The recent progress in nanotechnology.sup.1,2 and single-molecule spectroscopy.sup.3-5 paves the way for emergent cost-effective organic quantum optical technologies with potential applications in useful devices operating at ambient conditions. We harness a [pi]-conjugated ladder-type polymer strongly coupled to a microcavity forming hybrid light-matter states, so-called exciton-polaritons, to create exciton-polariton condensates with quantum fluid properties. Obeying Bose statistics, exciton-polaritons exhibit an extreme nonlinearity when undergoing bosonic stimulation.sup.6, which we have managed to trigger at the single-photon level, thereby providing an efficient way for all-optical ultrafast control over the macroscopic condensate wavefunction. Here, we utilize stable excitons dressed with high-energy molecular vibrations, allowing for single-photon nonlinear operation at ambient conditions. This opens new horizons for practical implementations like sub-picosecond switching, amplification and all-optical logic at the fundamental quantum limit. Nonlinearity induced by a single photon is desirable because it can drive power consumption of optical devices to their fundamental quantum limit, and is demonstrated here at room temperature.
Author(s): Anton V. Zasedatelev [sup.1] [sup.2] , Anton V. Baranikov [sup.1] [sup.2] , Denis Sannikov [sup.1] [sup.2] , Darius Urbonas [sup.3] , Fabio Scafirimuto [sup.3] , Vladislav Yu. Shishkov [sup.1] [...]