Improved Heralded Single-Photon Source with a Photon-Number-Resolving Superconducting Nanowire Detector
Deterministic generation of single photons is essential for many quantum information technologies. A bulk optical nonlinearity emitting a photon pair, where the measurement of one of the photons heralds the presence of the other, is commonly used with the caveat that the single-photon emission rate is constrained due to a trade-off between multiphoton events and pair emission rate. Using an efficient and low noise photon-number-resolving superconducting nanowire detector we herald, in real time, a single photon at telecommunication wavelength. We perform a second-order photon correlation g²(0) measurement of the signal mode conditioned on the measured photon number of the idler mode for various pump powers and demonstrate an improvement of a heralded single-photon source. We develop an analytical model using a phase-space formalism that encompasses all multiphoton effects and relevant imperfections, such as loss and multiple Schmidt modes. We perform a maximum-likelihood fit to test the agreement of the model to the data and extract the best-fit mean photon number μ of the pair source for each pump power. A maximum reduction of 0.118 ± 0.012 in the photon g²(0) correlation function at μ = 0.327 ± 0.007 is obtained, indicating a strong suppression of multiphoton emissions. For a fixed g²(0) = 7 × 10⁻³, we increase the single pair generation probability by 25%. Our experiment, built using fiber-coupled and off-the-shelf components, delineates a path to engineering ideal sources of single photons.
© 2022 American Physical Society. We acknowledge partial funding from the Department of Energy BES HEADS-QON Grant No. DE-SC0020376 (on applications related to transduction), QuantiSED SC0019219, and the AQT Intelligent Quantum Networks and Technologies (INQNET) research program. Partial support for this work is provided by the DARPA DSO DETECT, NASA SCaN, and Caltech/JPL PDRDF programs. S.I.D. and A.M. acknowledge partial support from the Brinson Foundation. Part of this research was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. We acknowledge productive discussions with Kayden Taylor, Sergio Escobar, Daniel Oblak, and Cristian Peña. We are grateful to Jason Trevor for technical assistance.
Published - PhysRevApplied.18.064007.pdf