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arXiv · 2109.09275

Experimental Observation of Partial Parity-Time Symmetry and Its Phase Transition with a Laser-Driven Cesium Atomic Gas

Yongmei Xue·Chao Hang·Yunhui He·Zhengyang Bai·Yuechun Jiao·Guoxiang Huang·Jianming Zhao·Suotang Jia
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Abstract

Realization and manipulation of parity-time (PT) symmetry in multidimensional systems are highly desirable for exploring nontrivial physics and uncovering exotic phenomena in non-Hermitian systems. Here, we report the first experimental observation of partial PT (pPT) symmetry in a cesium atomic gas coupled with laser fields, where a two-dimensional pPT-symmetric optical potential for probe laser beam is created. A transition of the pPT symmetry from an unbroken phase to a broken one is observed through changing the beam-waist ratio of the control and probe laser beams, and the domains of unbroken, broken, and non-pPT phases are also discriminated unambiguously. Moreover, we develop a technique to precisely determine the location of the exceptional point of the pPT symmetry breaking by measuring the asymmetry degree of the probe-beam intensity distribution. The findings reported here pave the way for controlling multidimensional laser beams in non-Hermitian systems via laser-induced atomic coherence, and have potential applications for designing new types of light amplifiers and attenuators

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Yongmei Xue, Chao Hang, Yunhui He, Zhengyang Bai, Yuechun Jiao, Guoxiang Huang, Jianming Zhao, Suotang Jia. 2021-09-20. Experimental Observation of Partial Parity-Time Symmetry and Its Phase Transition with a Laser-Driven Cesium Atomic Gas. https://doi.org/10.1103/physreva.105.053516

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