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arXiv · 2402.06113

Broadband tunable transmission non-reciprocity in thermal atoms dominated by two-photon transitions

Hui-Min Zhao·Di-Di Zheng·Xiao-Jun Zhang·Jin-Hui Wu
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Abstract

We propose a scheme for realizing broadband and tunable transmission non-reciprocity by utilizing two-photon near-resonant transitions in thermal atoms as single-photon far-detuned transitions can be eliminated. Our basic idea is to largely reduce the Doppler broadenings on a pair of two-photon, probe and coupling, transitions and meanwhile make the only four-photon transition Doppler-free (velocity-dependent) for a forward (backward) probe field. One main advantage of this scheme lies in that the transmission non-reciprocity can be realized and manipulated in a frequency range typically exceeding $200$ MHz with isolation ratio above $20$ dB and insertion loss below $1.0$ dB by modulating an assistant field in frequency and amplitude. The intersecting angle between four applied fields also serves as an effective control knob to optimize the nonreciprocal transmission of a forward or backward probe field, e.g. in a much wider frequency range approaching $1.4$ GHz.

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Hui-Min Zhao, Di-Di Zheng, Xiao-Jun Zhang, Jin-Hui Wu. 2024-02-09. Broadband tunable transmission non-reciprocity in thermal atoms dominated by two-photon transitions. https://arxiv.org/abs/2402.06113

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