Optical nonlinearity for few-photon pulses on a quantum dot-pillar cavity device

TL;DR

This paper demonstrates a record low photon threshold for optical nonlinearity in a quantum dot-micropillar system, enabling effective photon-photon interactions crucial for quantum information processing.

Contribution

It reports the first observation of giant optical nonlinearity at a record low of 8 incident photons per pulse in a strongly-coupled quantum dot-cavity system.

Findings

Achieved a nonlinearity threshold of only 8 photons per pulse.

Identified the importance of input and output coupling efficiencies.

Showed potential for single-photon nonlinearity in realistic devices.

Abstract

Giant optical nonlinearity is observed under both continuous-wave and pulsed excitation in a deterministically-coupled quantum dot-micropillar system, in a pronounced strong-coupling regime. Using absolute reflectivity measurements we determine the critical intracavity photon number as well as the input and output coupling efficiencies of the device. Thanks to a near-unity input-coupling efficiency, we demonstrate a record nonlinearity threshold of only 8 incident photons per pulse. The output-coupling efficiency is found to strongly influence this nonlinearity threshold. We show how the fundamental limit of single-photon nonlinearity can be attained in realistic devices, which would provide an effective interaction between two coincident single photons.