Quantum Technologies with single photons

Chao‐Yang Lu

Stefania Castelletto, Robert E Scholten

Single photon counting, based on single photon sources and detectors, is a key ingredient for certain applications aiming at new quantum information technologies. Quantum cryptography, quantum radiometry, distributed quantum computing, as well as adjacent technologies such as biomedical and astronomical imaging, and low power classical communication also rely on single-photon technology. This paper reviews the present status of single photon sources and related counting measurement techniques, based on correlated (or heralded) photons in parametric down-conversion, and their possible impact on the above mentioned technologies, as well as an assessment for photon standards in the future.

Chih‐Hsiang Wu, Tsung-Yao Wu, Yung-Chin Yeh +5 more

Single photons of subnatural linewidth and high spectral brightness are necessary for efficient light-matter interaction at the single-photon level, which lies at the heart of many quantum photonic technologies. Here we demonstrate a bright source of single photons with subnatural linewidth, controllable waveforms, and a high spectral brightness of $3.67\ifmmode\times\else\texttimes\fi{}{10}^{5}\phantom{\rule{4pt}{0ex}}\mathrm{s}{}^{\ensuremath{-}1}\phantom{\rule{4pt}{0ex}}\mathrm{mW}{}^{\ensuremath{-}1}\phantom{\rule{4pt}{0ex}}\mathrm{MHz}{}^{\ensuremath{-}1}$. The interaction between the single photons and atoms is demonstrated by the controlled absorption of the single photons in an atomic vapor. Our work has potential applications in quantum information technologies.

Martin Ringbauer

Martin Ringbauer

Nobuyuki Matsuda

We demonstrated a new scheme for wavelength conversion of a single-photon wave packet for use in quantum information communication technologies.The scheme enables us to deterministically change the color and shape of a single-photon wave packet in a lossless manner.The scheme is directly applicable to single photons traveling in an optical fiber network and will be a key technology in developing a photonic wavelength interface for quantum networking.