Hanbury Brown-Twiss interference with massively parallel spectral multiplexing for broadband light

Abstract: Two-photon interference in the spectral domain is a powerful resource for quantum technologies, enabling both precision measurements and scalable entanglement distribution. Here, we report the first demonstration of massively parallel, wavelength-resolved photon bunching, revealing Hanbury Brown-Twiss correlations across 100 independent spectral channels. These observations are enabled by a fast, data-driven single-photon spectrometer that achieves 40 pm spectral and 40 ps temporal resolution over a 10 nm bandwidth, allowing simultaneous access to spectro-temporal photon correlations without the need for narrowband filtering. This approach preserves photon flux while enabling high-dimensional quantum interference measurements across a broad spectrum. Our results establish frequency-multiplexed two-photon interference as a scalable and throughput-efficient platform for quantum-enhanced photonic technologies, with applications ranging from stellar intensity interferometry to broadband entanglement swapping in quantum networks.