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arXiv · 2111.06104

Nonreciprocal single-photon band structure

Jiangshan Tang·Wei Nie·Lei Tang·Mingyuan Chen·Xin Su·Yanqing Lu·Franco Nori·Keyu Xia
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Abstract

We study single-photon band structure in a one-dimensional (1D) coupled-resonator optical waveguide (CROW) which chirally couples to an array of two-level quantum emitters (QEs). The chiral interaction between the resonator mode and the QE can break the time-reversal symmetry without the magneto-optical effect. As a result, a nonreciprocal single-photon edge state, band gap and flat band appear. By using such a chiral QE-CROW system, including a finite number of unit cells and working in the nonreciprocal band gap, we achieve frequency-multiplex single-photon circulators with high fidelity and low insertion loss. The chiral QE-light interaction can also protect one-way propagation of single photons against backscattering. Our work opens a new door for studying nonreciprocal photonic band structure and exploring its applications in the quantum regime.

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Jiangshan Tang, Wei Nie, Lei Tang, Mingyuan Chen, Xin Su, Yanqing Lu, Franco Nori, Keyu Xia. 2021-11-11. Nonreciprocal single-photon band structure. https://doi.org/10.1103/physrevlett.128.203602

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