Design for an electrically-pumped photonic nanowire single-photon source with an efficiency of 89 %

Abstract

The development of high-efficiency solid-state single-photon sources (SPSs) is a major challenge within the fields of quantum communication and optical quantum information processing [1]. For these applications an efficiency of 100 % is desired, the efficiency being defined as the probability of detecting a photon at the collection optics per trigger. Traditional SPS devices feature a quantum dot (QD) embedded in an optical microcavity, where the Purcell effect is employed to ensure a good coupling of the QD to the optical mode of interest. However a large sensitivity to scattering by fabrication imperfections limits the efficiency of these cavity-based designs to ∼ 40 %. As an alternative, a SPS design based on a photonic nanowire was proposed [2]. This design features no cavity and instead an electromagnetic screening effect is used to ensure efficient coupling to the fundamental mode. The emitted photons escape immediately and are thus much less subject to the influence of imperfections than cavity-based approaches. An optically pumped nanowire SPS with a measured efficiency of 72 % was recently demonstrated [3] validating the nanowire SPS design approach. However, for practical applications electrical pumping is desired. Metals strongly scatter and absorb light and the implementation of metal contacts while maintaining a high efficiency is not trivial.