Coherent Optical Spectroscopy of a Single Quantum Dot Via an Off-Resonant Cavity

TL;DR

This paper demonstrates that off-resonant cavity emission can reveal coherent interactions in quantum dot systems, providing a simpler method to probe and potentially interface quantum dots in quantum networks.

Contribution

It shows that incoherent phonon-mediated processes can preserve signatures of coherence, enabling optical dressing detection via off-resonant cavity emission.

Findings

Spectral features indicate optical dressing of the QD transition.

Off-resonant cavity emission reveals coherent QD-cavity interactions.

Method offers a new way to probe QDs coherently.

Abstract

In recent experiments on coupled quantum dot (QD) optical cavity systems a pronounced interaction between the dot and the cavity has been observed even for detunings of many cavity linewidths. This interaction has been attributed to an incoherent phonon-mediated scattering process and is absent in atomic systems. Here, we demonstrate that despite its incoherent nature, this process preserves the signatures of coherent interaction between a QD and a strong driving laser, which may be observed via the optical emission from the off-resonant cavity. Under bichromatic driving of the QD, the cavity emission exhibits spectral features consistent with optical dressing of the QD transition. In addition to revealing new aspects of the off-resonant QD-cavity interaction, this result provides a new, simpler means of coherently probing QDs than traditional approaches and opens the possibility of employing off-resonant cavities to optically interface QD-nodes in quantum networks.