Improved Heralded Single-Photon Source with a Photon-Number-Resolving Superconducting Nanowire Detector

• DOI: 10.1103/physrevapplied.18.064007
• Publication Date: 2022-12-02T16:15:53Z
• Authors: Samantha I. Davis; Andrew Mueller; Raju Valivarthi; Nikolai Lauk; Lautaro Narvaez; Boris Korzh; Andrew D. Beyer; Olmo Cerri; Marco Colangelo; Karl K. Berggren; Matthew D. Shaw; Si Xie; Neil Sinclair; Maria Spiropulu
• Keywords: Quantum Physics; 0103 physical sciences; General Physics and Astronomy; 500; FOS: Physical sciences; Quantum Physics (quant-ph); 530; 01 natural sciences; Physics - Optics; Optics (physics.optics)

Model and analysis integrated into main text. Corrected equations. 17 pages, 11 figures<br/>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 $g^{2}(0)$ 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 $0.118 \pm 0.012$ in the photon $g^{2}(0)$ correlation function at $μ= 0.327 \pm 0.007$ is obtained, indicating a strong suppression of multiphoton emissions. For a fixed $g^{2}(0) = 7e-3$, 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.<br/>