Single Photons from a Single Atom

Orel Bechler, Serge Rosenblum, Itay Shomroni +3 more

We demonstrate a passive scheme for deterministic interactions between a single photon and a single atom. Relying on single-photon Raman interaction (SPRINT), this control-fields free scheme swaps a flying qubit, encoded in the two possible input modes of a photon, with a stationary qubit, encoded in the two ground states of the atom, and can be also harnessed to perform universal quantum gates. Using SPRINT we experimentally demonstrated all-optical switching of single photons by single photons, and deterministic extraction of a single photon from an optical pulse. Applicable to any atom-like Lambda system, SPRINT provides a versatile building block for scalable quantum networks based on completely passive nodes interconnected and activated solely by single photons.

Vladan Vuletić, Adam T. Black, James K. Thompson

Victor Leong, Mathias Alexander Seidler, Matthias Steiner +2 more

Scattering of light by matter has been studied extensively in the past. Yet, the most fundamental process, the scattering of a single photon by a single atom, is largely unexplored. One prominent prediction of quantum optics is the deterministic absorption of a travelling photon by a single atom, provided the photon waveform matches spatially and temporally the time-reversed version of a spontaneously emitted photon. Here we experimentally address this prediction and investigate the influence of the photon's temporal profile on the scattering dynamics using a single trapped atom and heralded single photons. In a time-resolved measurement of atomic excitation we find a 56(11)% increase of the peak excitation by photons with an exponentially rising profile compared with a decaying one. However, the overall scattering probability remains unchanged within the experimental uncertainties. Our results demonstrate that envelope tailoring of single photons enables precise control of the photon-atom interaction.

Victor Leong

Anonymous

Wenan Li, Xiaoshi Li, Jin-Jiang Huang +3 more

We investigate controllable single-photon transport in a one-dimensional coupled-resonator waveguide coupled to two nanocavities interacting with atoms. The reflection and transmission coefficients for a single photon propagating in such a system are deduced by using the discrete coordinates approach. The resonator–nanocavity coupling strength, atom–nanocavity coupling coefficient, and the detuning between the incident photon and the atom, respectively, which affect the transport properties of the single photon, are analyzed. It is found that some useful information, such as the atom–nanocavity coupling strength, can be extracted from the single-photon transmission spectrum under proper parameter settings. We also study how the coupling between two nanocavities affects the single-photon transmission property.