Unconventional time-bandwidth performance of resonant cavities with nonreciprocal coupling

Ivan Cardea, Davide Grassani, Jeremy Upham, Sebastian Andreas Schulz, Kosmas L. Tsakmakidis, Camille-Sophie Bres*

*Corresponding author for this work

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The time-bandwidth limit is a mathematical tenet that affects all reciprocal resonators, stating that the product of the spectral bandwidth that can couple into a resonant system and its characteristic energy decay time is always equal to 1. Here, we develop an analytical and numerical model to show that introducing nonreciprocal coupling to a generalized resonator changes the power balance between the reflected and intracavity fields, which consequently overcomes the time-bandwidth limit of the resonant system. By performing a full evaluation of the time-bandwidth product (TBP) of the modeled resonator, we show that it represents a measure of the increased delay imparted to a light wave, with respect to what the bandwidth of the reciprocal resonant structure would allow to the same amount of in-coupled power. No longer restricted to the value 1, we show that the TBP can instead be used as a figure of merit of the improvement in intracavity power enhancement due to the nonreciprocal coupling.
Original languageEnglish
Article number013716
JournalPhysical Review. A, Atomic, molecular, and optical physics
Issue number1
Publication statusPublished - 12 Jan 2021


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