Laser Physics Letters

Tunable single-photon scattering and nonreciprocal transmission in a waveguide coupled nonlocally to a giant-atom-like scatterer

Y F Zhu, Z H Zhu, Y Q Zhang, Zhihui Peng, Yi-Feng Chai

Published Aug 1, 2026• 0 citations

Abstract

Abstract We explore the scattering and nonreciprocal transmission of single photons in an array of N coherently coupled two-level atoms, with only the two end atoms interacting with a waveguide at distinct spatial points. The chain serves as a giant-atom-like scatterer with internal collective modes. Using the real-space approach, analytical expressions for the scattering amplitudes are obtained. For the ideal case without atomic loss, the transmission is reciprocal and can be modulated by the relative local coupling phase, the accumulated propagation phase, the interatomic hopping strength, and the photon–atom detuning. We further observe that the oscillatory behavior of the transmission spectrum becomes more pronounced as the number of atoms increases. When atomic loss into nonguided modes is included, phase-dependent interference gives rise to dissipation-assisted nonreciprocal transmission. By appropriately tuning the phase factors, the atomic loss rate, and the hopping strength, one can achieve maximal nonreciprocity, corresponding to complete suppression of transmission for one incident direction. These results establish a flexible platform for engineering directional single-photon transport in guided-wave quantum electrodynamics.

DOI: 10.1088/1612-202x/ae95ed

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