Non-Hermitian optics is a burgeoning field at the intersection of quantum physics, electrodynamics, and nanophotonics. It provides a new perspective of the role of gain and loss in optical systems. Leveraging the advanced designs inspired by non-Hermitian physics, classical optical platforms have been widely investigated to unveil novel physical concepts, such as parity-time symmetry and exceptional points, which have no counterparts in the conventional Hermitian settings. These investigations have yielded a plethora of new phenomena in optical wave scattering, optical sensing, and nonlinear optical processes. Non-Hermitian effects also have a profound impact on the lasing behaviors in the semiclassical framework of lasers, allowing for novel ways to engineer single-mode lasers, chiral laser emission, laser noise, linewidth, etc. Furthermore, over recent years, there has been increasing interest in the explorations of non-Hermitian physics in quantum optics, which addresses photon statistics, entanglement, decoherence, and quantum sensing in non-Hermitian systems. In this review, we review the most recent theoretical and experimental advances in non-Hermitian optics and photonics, covering the significant progress in both classical and quantum optics regimes.

中文翻译：

---

非厄米光学和光子学：从经典到量子

非厄米光学是量子物理学、电动力学和纳米光子学交叉领域的一个新兴领域。它为光学系统中增益和损耗的作用提供了新的视角。利用受非厄米物理学启发的先进设计，经典光学平台已被广泛研究，以揭示新颖的物理概念，例如宇称时间对称性和例外点，这些概念在传统厄米设置中没有对应物。这些研究在光波散射、光学传感和非线性光学过程中产生了大量新现象。非厄米效应也对激光器的半经典框架中的激光行为产生深远的影响，从而提供了设计单模激光器、手性激光发射、激光噪声、线宽等的新方法。此外，近年来，人们对量子光学中的非厄米物理学的探索越来越感兴趣，它解决了非厄米系统中的光子统计、纠缠、退相干和量子传感问题。在这篇综述中，我们回顾了非厄米光学和光子学的最新理论和实验进展，涵盖了经典光学和量子光学领域的重大进展。