High performance single photon sources and their application to quantum technologies

John Rarity, Stephen C. Kitson, Paul R. Tapster

Yang Yu, Chunran Li, Yanan Yu +4 more

High-performance single-photon sources (SPSs) are essential components for quantum information technology and have been realized by strong coupling between a single quantum emitter and an optical cavity. However, the configurations of conventional SPSs are not ideal for long-distance quantum communication as they are intrinsically incompatible with optical fibers. Here we propose and design a strong-coupling system based on a single quantum emitter directly coupled with an in-fiber microcavity. The in-fiber microcavity not only achieves a high coupling efficiency of 83% and a high Purcell factor of 360, but also pushes the coupling system to enter the strong-coupling region with a vacuum Rabi splitting up to 4.35 meV. This enables a high quantum efficiency of 99% for a SPS. Our work presents a promising platform for realizing high-performance SPSs for long-distance quantum communication.

Catherine R. M. Fitzpatrick, Chandra M. Natarajan, Ryan E. Warburton +8 more

Single-photon sources and detectors are key enabling technologies for photonics in quantum information science and technology (QIST). QIST applications place high-level demands on the performance of sources and detectors; it is therefore essential that their properties can be characterized accurately. Superconducting nanowire single-photon detectors (SNSPDs) have spectral sensitivity from visible to beyond 2 μm in wavelength, picosecond timing resolution (Jitter <100 ps FWHM) and the capacity to operate ungated with low dark counts (<1 kHz). This facilitates data acquisition at high rates with an excellent signal-to-noise ratio. We report on the construction and characterization of a two-channel SNSPD system. The detectors are mounted in a closed-cycle refrigerator, which eliminates reliance on liquid cryogens. Our specification was to deliver a system with 1% efficiency in both channels at a wavelength of 1310 nm with 1 kHz dark count rate. A full width at half maximum timing jitter of less than 90 ps is achieved in both channels. The system will be used to detect individual photons generated by quantum-optical sources at telecom wavelengths. Examples include single-photon sources based on quantum dots (emitting at 1310 nm). The SNSPD system's spectral sensitivity and timing resolution make it suited to characterization of such sources, and to wider QIST applications.

鋭博 金

Jennifer Ann Hollingsworth

Igor I. Vlasov, Alexey M. Romshin, Dmitrii G. Pasternak +2 more

Abstract Single photon sources (SPSs) are one of the key components in quantum communication technology. Here we report on the development of a new approach to the controlled formation of SPSs in nanodiamonds synthesized from hydrocarbons at high pressure and high temperature (HPHT). The conditions of HPHT synthesis were determined, allowing for the highly efficient production of scalable single-photon emitters based on single silicon-vacancy (SiV) centers in individual diamond particles of 250-300 nm in size. A new type of SPSs, emitting in a wide spectral range (500-800 nm) at room temperature, was found in hydrogen-terminated nanodiamonds. The recorded rate of the SPS emission exceeds 1 million photons per second. The HPHT nanodiamonds containing both SiV and the new emitters are a promising material for quantum photonics applications.