Abstract: Photon indistinguishability is essential for quantum interference underpinning emerging applications in quantum sensing, communication, and computing. Compelling motivations under investigation in my group include quantum astrometry, where two-photon interference can enable long-baseline optical interferometry without direct optical links between telescopes, and quantum networks, where wavelength-multiplexed entanglement swapping promises substantially enhanced communication rates. Both applications require efficient identification of indistinguishable photons with high temporal and spectral precision.
We present an approach to photon indistinguishability detection based on ultrafast spectro-temporal imaging with pixelated single-photon detectors. By mapping detected photons onto well-defined time–frequency modes, the method enables identification of interfering photon pairs and higher-order correlations. Our spectrometer based on the LinoSPAD2 SPAD array achieves approximately 40 ps timing and 40 pm spectral resolution. We demonstrate massively parallel, wavelength-resolved Hanbury Brown–Twiss interference with broadband light across approximately 100 independent spectral channels, exceeding previous multiplexing capabilities by more than an order of magnitude [1].
We discuss recent improvements in spectral resolution and prospects for next-generation two-dimensional detector arrays approaching the Heisenberg–Gabor limit, with target resolutions of 20 ps and 5 pm. The approach offers a scalable path toward real-time photon indistinguishability selection, substantially reduced data volumes, and multiphoton correlation measurements, opening new opportunities for quantum-enhanced astronomical interferometry, entanglement swapping, and quantum imaging.
[1] Hanbury Brown-Twiss interference with massively parallel spectral multiplexing for broadband light, S Kulkov et al, Advanced Photonics Nexus, Vol.5, Issue 5, 056023 (2026), arXiv:2509.05649 (2025).
About the Speaker: Andrei Nomerotski is a Senior Researcher at the Czech Technical University in Prague (since 2024) and a Courtesy Professor at Florida International University, USA (since 2023). His research interests span experimental particle and quantum physics, astrophysics, and the development and applications of fast imaging cameras for single photon detection.Previously, he was a Research Professor at Stony Brook University (2015–2024) and a Physicist at Brookhaven National Laboratory (2012–2023). From 2005 to 2012, he held academic positions at the University of Oxford (2005–2012). Earlier in his career, he was a scientist at Fermilab (2000–2005) and a postdoctoral researcher at the University of Florida (1996–2000).He received his PhD in Physics from the University of Padua in 1996, with a thesis on semileptonic B-meson decays, and his MS degree from Novosibirsk State University.
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