Prof. Stephan Götzinger

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).

In a previous paper [Nat. Photon. 5, 166 ( 2011)], we reported on a planar dielectric antenna that achieved 96% efficiency in collecting the photons emitted by a single molecule. In that work, the transition dipole moment of the molecule was set perpendicular to the antenna plane. Here, we present a theoretical extension of that scheme that reaches collection efficiencies beyond 99% for emitters with arbitrarily oriented dipole moments. Our work opens important doors in a wide range of contexts including quantum optics, quantum metrology, nanoanalytics, and biophysics. In particular, we provide antenna parameters to realize ultrabright single-photon sources in high-index materials such as semiconductor quantum dots and color centers in diamond, as well as sensitive detection of single molecules in nanofluidic devices. (C) 2011 Optical Society of America