A planar dielectric antenna for directional single-photon emission and near-unity collection efficiency

Single emitters have been considered as sources of single photons in various contexts, including cryptography, quantum computation, spectroscopy and metrology(1-3). The success of these applications will crucially rely on the efficient directional emission of photons into well-defined modes. To accomplish high efficiency, researchers have investigated microcavities at cryogenic temperatures(4,5), photonic nanowires(6,7) and near-field coupling to metallic nano-antennas(8-10). However, despite impressive progress, the existing realizations substantially fall short of unity collection efficiency. Here, we report on a theoretical and experimental study of a dielectric planar antenna, which uses a layered structure to tailor the angular emission of a single oriented molecule. We demonstrate a collection efficiency of 96% using a microscope objective at room temperature and obtain record detection rates of similar to 50 MHz. Our scheme is wavelength-insensitive and can be readily extended to other solid-state emitters such as colour centres(11,12) and semiconductor quantum dots(13,14).