Thermal-motion-induced non-reciprocal quantum optical system

• Published in: Nature photonics Vol. 12; no. 12; pp. 744 - 748
• Main Authors: Zhang, Shicheng, Hu, Yiqi, Lin, Gongwei, Niu, Yueping, Xia, Keyu, Gong, Jiangbin, Gong, Shangqing
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.12.2018; Nature Publishing Group
• Subjects: 140/125; 639/624; 639/766/400/482; Applied and Technical Physics; Isolators; Letter; Magnetic permeability; Optical communication; Optics; Physics; Physics and Astronomy; Quantum optics; Quantum Physics; Quantum theory; Reciprocity; Signal processing
• ISSN: 1749-4885; 1749-4893
• DOI: 10.1038/s41566-018-0269-2

Magnetic-free optical non-reciprocal components, such as isolators and circulators, are highly desirable for on-chip optical signal processing 1 , 2 and quantum networks 3 , 4 . However, their realization presents a fundamental difficulty due to the Lorentz reciprocity in most optical devices 5 . In this study, we propose and experimentally realize optical non-reciprocity with atoms embedded in a ring cavity at room temperature. Random thermal motion of atoms, in the presence of a unidirectional control field, creates susceptibility–momentum locking, and subsequently a new type of chiral quantum optical system. Furthermore, we demonstrate strong non-reciprocity based on this chiral quantum system in the regime of collectively strong atom–cavity coupling. Our scheme provides a new routine towards the realization of chiral quantum optics and chip-compatible, non-magnetic optical non-reciprocity. Optical non-reciprocity is experimentally realized with Rb atoms embedded in a ring cavity at room temperature. Random thermal motion of the atoms causes the probe-direction-dependent response assisted by a unidirectional control laser field.