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arXiv · 2510.01836

Hybrid biphoton spectrometer for time-resolved quantum spectroscopy across visible and near-infrared regions

Ozora Iso·Koya Onoda·Nicola J. Fairbairn·Masahiro Yabuno·Hirotaka Terai·Shigehito Miki·Ryosuke Shimizu
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Abstract

Joint spectral measurements are a powerful tool for characterising biphoton spectral correlation, which is crucial for quantum information and communication technologies. In these applications, highly pure biphoton states are essential in any time- and frequency-mode, often obviating the need for time-resolved measurements. Conversely, spectroscopy utilising entangled photon pairs is gaining significant attention for its ability to unveil molecular dynamics, a field that critically demands time-resolved capabilities. Here, we introduce a methodology for capturing a biphoton spectrum that comprises visible and near-infrared photons, resulting in a highly non-degenerate joint spectrum. Our system employs two non-scanning spectrographs: a fibre spectrometer for near-infrared photons and a delay-line-anode single-photon imager for visible photons. We successfully measure the joint spectral intensity by leveraging a time-tagging acquisition strategy. Furthermore, our approach uniquely enables time-resolved joint spectral measurements with respect to the laser synchronisation against the hundreds-of-picosecond instrument response function. Our methodology could advance heralded fluorescence spectroscopy using biphoton sources to investigate temporal dynamics of complex biological, chemical, and physical systems.

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Ozora Iso, Koya Onoda, Nicola J. Fairbairn, Masahiro Yabuno, Hirotaka Terai, Shigehito Miki, Ryosuke Shimizu. 2025-10-02. Hybrid biphoton spectrometer for time-resolved quantum spectroscopy across visible and near-infrared regions. https://arxiv.org/abs/2510.01836

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