Tapered nanowire antennas have emerged as a versatile solid-state platform for quantum optics. These broadband photonic structures efficiently funnel the spontaneous emission of an embedded quantum dot into a directive free-space beam. They find application in the realization of bright sources of quantum light, and enable the implementation of giant optical non-linearities, at the single-photon level.
In this work, we discuss advances aiming at further optimizing this light-matter interface. In particular, recent measurements revealed that the thermal excitation of a single nanowire vibration mode can have a sizeable influence on the quantum dot optical linewidth. This motivated a comprehensive theoretical analysis, which shows that the thermally-driven vibrations of the nanowire have a major impact on the quantum dot light emission spectrum. Even at liquid helium temperatures, these prevent the emission of indistinguishable photons. To overcome this intrinsic limitation, we propose several designs that restore photon indistinguishability thanks to a specific engineering of the mechanical properties of the nanowire. We anticipate that such a mechanical optimization will also play a key role in the development of other high-performance light-matter interfaces based on nanostructures.