Telecom-heralded single-photon absorption by a single atom
Andreas Lenhard, Matthias Bock, Christoph Becher, Stephan Kucera, José Luis Saquinaula Brito, Pascal Eich, Philipp Müller, Jürgen Eschner · Physical Review A · 2015
We present, characterize, and apply the architecture of a photonic quantum interface between the near infrared and telecom spectral regions. A singly resonant optical parametric oscillator (OPO) operated below threshold, in combination with external filters, generates high-rate ($>2.5\ifmmode\times\else\texttimes\fi{}{10}^{6}\phantom{\rule{0.222222em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$) narrowband photon pairs ($\ensuremath{\sim}7$ MHz bandwidth); the signal photons are tuned to resonance with an atomic transition in ${\mathrm{Ca}}^{+}$, while the idler photons are at telecom wavelength. Interface operation is demonstrated through high-rate absorption of single photons by a single trapped ion ($\ensuremath{\sim}670\phantom{\rule{0.222222em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$), heralded by coincident telecom photons.