Enhanced third-order and fifth-order Kerr nonlinearities in a cold atomic system via Rydberg-Rydberg interaction

TL;DR

This paper demonstrates significantly enhanced third- and fifth-order Kerr nonlinearities in cold Rydberg atomic systems under EIT, highlighting the dominant role of Rydberg-Rydberg interactions at high densities for quantum applications.

Contribution

It introduces a beyond mean-field approach showing giant fifth-order nonlinear susceptibility in Rydberg-EIT systems, surpassing traditional systems.

Findings

Fifth-order susceptibility can be five orders of magnitude larger than in traditional EIT.

Both third- and fifth-order nonlinearities are influenced by photon-atom and Rydberg-Rydberg interactions.

Rydberg-Rydberg interaction dominates at high atomic densities.

Abstract

We investigate the optical Kerr nonlinearities of an ensemble of cold Rydberg atoms under the condition of electromagnetically induced transparency (EIT). By using an approach beyond mean-field theory, we show that the system possesses not only enhanced third-order nonlinear optical susceptibility, but also giant fifth-order nonlinear optical susceptibility, which has a cubic dependence on atomic density. Our results demonstrate that both the third-order and the fifth-order nonlinear optical susceptibilities consist of two parts, contributed respectively by photon-atom interaction and Rydberg-Rydberg interaction. The Kerr nonlinearity induced by the Rydberg-Rydberg interaction plays a leading role at high atomic density. We find that the fifth-order nonlinear optical susceptibility in the Rydberg-EIT system may be five orders of magnitude larger than that obtained in traditional EIT systems. The results obtained may have promising applications in light and quantum information processing and transmission at weak-light level.