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arXiv · 2602.04646

Pure narrowband photon-pair generation in a monolithic cavity

Xavier Barcons Planas·Helen M. Chrzanowski·Janik Wolters
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Abstract

Photonic quantum technologies require efficient sources of pure single photons. We present a heralded single-photon source based on spontaneous parametric down-conversion in a monolithic cavity optimized for high spectral and spatial purity. The source heralds single photons at a wavelength of 1540 nm and a spectral bandwidth of 168 MHz, with a maximum heralding efficiency of 70% including all transmission and detection losses, while keeping the multi-photon contamination below 3%. The cavity enhancement predominantly generates photons into the central cavity mode, with a theoretical upper bound on the spectral purity of 79.4% arising from nonzero overlap with adjacent cavity modes. Spectral isolation of the central cavity mode with an etalon yields an increased measured spectral purity of (96.2 $\pm$ 2.7)%.

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Xavier Barcons Planas, Helen M. Chrzanowski, Janik Wolters. 2026-02-04. Pure narrowband photon-pair generation in a monolithic cavity. https://arxiv.org/abs/2602.04646

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