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Updated: Aug 5, 2026

In Situ Measurement of Vacuum Window Birefringence using 25Mg+ Fluorescence
Published on: June 13, 2020
Fano resonance from backscattering in a magnesium fluoride crystalline cavity for laser frequency locking
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We report the Fano resonance induced by backscattering in a MgF₂ WGM cavity. The reflected light from the tapered fiber end facet acts as the continuum in Fano interference, with its phase adjustable to produce various Fano lineshapes. We modeled this effect and identified the optimal parameters for laser frequency locking. With the high-Q factor and low thermal noise of the MgF₂ WGM cavity, effective suppression of laser frequency noise was achieved. This work demonstrates a compact, robust, modulation-free laser frequency-locking method for miniaturized low-noise lasers.
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