Single-photon nonlinearity at room temperature

The recent progress in nanotechnology(1,2) and single-molecule spectroscopy(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(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.

Automated summary

Recent progress in nanotechnology and single-molecule spectroscopy has enabled the development of cost-effective organic quantum optical technologies for use in devices operating at ambient conditions. By triggering nonlinearity at the single-photon level, researchers have efficiently controlled the macroscopic condensate wavefunction of exciton-polariton condensates.