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arXiv · 2507.23617

Quasi-continuous sub-$μ$K strontium source without a high-finesse cavity stabilized laser

Sana Boughdachi·Benedikt Heizenreder·Ananya Sitaram·Erik Dierikx·Yan Xie·Sander Klemann·Paul Klop·Jeroen Koelemeij·Rafał Wilk·Florian Schreck·Andreas Brodschelm
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Abstract

We demonstrate a quasi-continuous sub-$μ$K strontium source achieved without the use of a high-finesse cavity-locked laser. Our frequency reference is based on a dispersion-optimized, fiber-based frequency comb that enables sub-kHz linewidths. The long-term stability of the comb is defined by an external RF reference: either a 10 MHz RF signal from the Dutch Metrology Institute (VSL), or a tunable RF source whose long-term stability is maintained by monitoring and stabilizing the position of a narrow-line magneto-optical trap (MOT). The comb-stabilized system is benchmarked against a conventional cavity-locked laser and achieves comparable performance in broadband and single-frequency MOTs using the narrow $^1$S$_0$ $\rightarrow$ $^3$P$_1$ laser cooling transition. We generate high-flux, sub-$μ$K samples of all three bosonic strontium isotopes and demonstrate quasi-continuous outcoupling from the MOT. These results highlight the system's suitability for compact, robust, and field-deployable continuous cold atom devices.

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Sana Boughdachi, Benedikt Heizenreder, Ananya Sitaram, Erik Dierikx, Yan Xie, Sander Klemann, Paul Klop, Jeroen Koelemeij, Rafał Wilk, Florian Schreck, Andreas Brodschelm. 2026-02-19. Quasi-continuous sub-$μ$K strontium source without a high-finesse cavity stabilized laser. https://doi.org/10.1103/3gnx-4s97

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