Two-photon absorption and emission by Rydberg atoms in coupled cavities

TL;DR

This paper investigates how coupled cavities with Rydberg atoms can facilitate two-photon absorption and emission, acting as a quantum nonlinear filter and enhancing photon emission through atom-cavity interactions.

Contribution

It introduces a novel system combining Rydberg atoms and coupled cavities to control two-photon processes and generate non-classical light states.

Findings

System acts as a quantum nonlinear absorption filter.

Enhanced two-photon emission due to vacuum field stimulation.

Selective two-photon resonance enabled by photon number-dependent energy levels.

Abstract

We study the dynamics of a system composed of two coupled cavities, each containing a single Rydberg atom. The interplay between Rydberg-Rydberg interaction and photon hopping enables the transition of the atoms from the collective ground state to the double Rydberg excitation state by individually interacting with the hybrid cavity modes and suppressing the up conversion process between them. The atomic transition is accompanied by the two-photon absorption and emission of the hybrid modes. Since the energy level structure of the atom-cavity system is photon number dependent, there is only a pair of states being in the two-photon resonance. Therefore, the system can act as a quantum nonlinear absorption filter through the nonclassical quantum process, converting coherent light field into a non-classical state. Meanwhile, the vacuum field in the cavity inspires the Rydberg atoms to simultaneously emit two photons into the hybrid mode, resulting in obvious emission enhancement of the mode.