SAMOP 2023 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 42: Poster III
Q 42.32: Poster
Wednesday, March 8, 2023, 16:30–19:00, Empore Lichthof
A few-MHz linewidth tunable optical filter based on a fibre-ring-resonator — •Gabriele Maron, Xinxin Hu, Luke Masters, Jürgen Volz, and Arno Rauschenbeutel — Department of Physics, Humboldt Universität zu Berlin, 10099 Berlin, Germany
We present a design for an ultra-narrowband, tunable optical filter, which is based on a fibre ring resonator. It consists of a fibre coupler with a variable splitting ratio, which allows us to set the filter linewidth and on-resonance transmission. At the same time, we set and actively stabilize the central frequency of the filter by means of actuators that change the optical round trip length of the fibre-ring. Operated in a notch-filter configuration, we recently used this device to isolate and investigate the incoherent emission from a single optically trapped atom, which was excited with near-resonant laser light [1]. The addition of a second variable fibre coupler into the fibre-ring extends the device’s utility for filtering in an add-drop configuration. In this case, our characterisation reveals a resonator linewidth significantly narrower than the D2 transition of 85Rb, while maintaining a high transmission into the drop port. The tunability of the filter properties presents our device as a versatile platform for selective frequency filtering with a subnatural atomic linewidth resolution.
[1] L. Masters et al, arXiv:2209.02547 (2022)