Our new paper on Non-Hermitian Anharmonicity Induces Single-Photon Emission has been published in Physical Review Letters!

Single-photon sources are essential building blocks for quantum information technologies. Typically, single-photon emission is achieved through energy-level anharmonicity, where absorption of one photon shifts the system out of resonance and prevents absorption of a second photon. In this work, we identify a fundamentally new mechanism: non-Hermitian anharmonicity - anharmonicity in the losses rather than in the energy levels.

We demonstrate this novel mechanism in two types of systems, including a feasible hybrid metallodielectric cavity weakly coupled to a two-level emitter. This approach enables high-purity single-photon emission at high repetition rates, opening new possibilities for quantum optical devices.

This work was led by Anael Ben-Asher and performed in collaboration with Antonio I. Fernández Domínguez from UAM.