Non-Hermitian Nonlinear Optics without Gain and Loss
Non-Hermitian Nonlinear Optics without Gain and Loss
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DOI：
10.1364/nlo.2019.nm2b.5
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发表时间：
2019-01
期刊：
影响因子：
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通讯作者：
Yue Jiang;Yefeng Mei;Ying Zuo;Yanhua Zhai;J. Wen;Shengwang Du
中科院分区：
文献类型：
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作者：
Yue Jiang;Yefeng Mei;Ying Zuo;Yanhua Zhai;J. Wen;Shengwang Du
具有奇偶时间(PT)对称性的非厄米光学系统最近显示出许多有趣的前景和优于保守结构的性能。不管它们与量子起源无关，这些作品大多植根于复杂的安排，具有受控的得失相互作用。然而，到目前为止，大多数实验实现都局限于线性或单模非线性光学。在这里，我们首次报道了基于四波混频的PT对称非线性光学在激光冷却原子系综中的实验演示，其增益和损耗可以忽略不计。由于二维磁光囚禁技术的最新进展，光学厚度的动态变化使斯托克斯和反斯托克斯这对模经历了从光学振荡到放大的突变相变。与传统研究要求完美的相位匹配不同，对于大相位失配的斯托克斯和反斯托克斯，本文实现了高效的非线性变换。因此，我们的结果将非线性光学扩展到了以前不利的领域，在那里可以预见新的现象和在激光和量子光学中的应用。
Non-Hermitian optical systems with parity-time (PT) symmetry have recently revealed many intriguing prospects and outperforming conservative structures. Regardless of their irrelevance of quantum origin, these works are mostly rooted in complex arrangements with controlled gain-loss interplay. To date, however, most experimental implementations are limited to either linear or single-mode nonlinear optics. Here, we report the first experimental demonstration of PT-symmetric nonlinear optics based upon four-wave mixing in a laser-cooled atomic ensemble with negligible gain and loss. Thanks to recent technical advances in two-dimensional magneto-optical trapping, dynamical change of optical depth enables the pair of modes, Stokes and anti-Stokes, to undergo an abrupt phase transition from optical oscillation to amplification. In contrast to conventional research demanding perfect phase matching, here efficient nonlinear conversion is achieved for Stokes and anti-Stokes with large phase mismatch. Our results thus extend nonlinear optics to previously unfavorable domain where new phenomena and applications in lasers and quantum optics could be envisioned.