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arXiv · 2503.15214

Single photon isolation and nonreciprocal frequency conversion in atom-waveguide systems

Jun-Cong Zheng·Xiao-Wei Zheng·Xin-Lei Hei·Yi-Fan Qiao·Xiao-Yu Yao·Xue-Feng Pan·Yu-Meng Ren·Xiao-Wen Huo·Peng-Bo Li
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Abstract

In this work, we utilize a two-level atom and a ${\Lambda}$-type atom to link two identical waveguides, subsequently extending the model to a giant-atom configuration. Our analytical solutions and numerical simulations demonstrate that this setup can achieve single-photon isolation and nonreciprocal frequency conversion by tuning the atom-waveguide coupling strengths $g_i$, respectively. We also examine single-photon scattering in the giant-atom model within both the Markovian and non-Markovian regimes. The results reveal that ultranarrow scattering windows are induced by the phases ${\phi}_1$ and ${\phi}_2$ under specific conditions, making them well-suited for precise frequency conversion and sensing. Additionally, in the non-Markovian regime, the spectra exhibit irregular polygonal shapes, offering enhanced opportunities for exploring nonreciprocal frequency conversion in the off-resonant regime. Our work provides a new perspective on achieving optical nonreciprocity at the single-photon level in atom-waveguide systems.

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Jun-Cong Zheng, Xiao-Wei Zheng, Xin-Lei Hei, Yi-Fan Qiao, Xiao-Yu Yao, Xue-Feng Pan, Yu-Meng Ren, Xiao-Wen Huo, Peng-Bo Li. 2025-03-19. Single photon isolation and nonreciprocal frequency conversion in atom-waveguide systems. https://arxiv.org/abs/2503.15214

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