Ultrafast Intercavity Nonlinear Couplings between Polaritons

Realizing nonlinear coupling across space can enable new scientific and technological advances, including ultrafast operation and propagation of information in IR photonic circuitry, remote triggering or catalyzing of chemical reactions, and new platforms for quantum simulations with increased complexities. In this report, we show that ultrafast nonlinear couplings are achieved between polaritons residing in different cavities, in the mid-infrared (IR) regime, e.g. by pumping polaritons in one cavity, the polaritons in the adjacent cavity can be affected. By hybridizing photon and molecular vibrational modes, molecular vibrational polaritons are formed that have the combined characteristic of both photon delocalization and molecular nonlinearity. Thus, although photons have little nonlinear coupling cross-section, and molecular nonlinearity is localized, the dual photon/molecule character of polaritons allows photons to affect each other across different cavities, through coupling to the same molecules - a novel property that neither molecular nor cavity mode would possess alone.