Parity-time symmetry and coherent perfect absorption in a cooperative atom response
Parity-time symmetry and coherent perfect absorption in a cooperative atom response
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DOI：
10.1515/nanoph-2020-0635
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发表时间：
2021-04-01
期刊：
影响因子：
7.5
通讯作者：
Ruostekoski, Janne
中科院分区：
文献类型：
--
作者：
Ballantine, Kyle E.;Ruostekoski, Janne
宇称-时间（PT）对称性已经成为合成光学材料设计中的一个重要概念，具有单向传输和非互易反射等奇异功能。在特殊的点，这种对称性是自发破缺，和解决方案过渡，从那些保守的强度指数增长或衰减。在这里，我们分析了一个量子光子表面形成的单层原子阵列与光介导的强合作多体相互作用。我们展示了如何离域集体激发本征模可以表现出有效的PT对称性和非指数衰减。这种有效的对称性是在无源系统中实现的，通过平衡亮模式的散射与次辐射暗模式的损失而没有增益。这些模式在特殊的点合并，证明了相干完美吸收的出现，其中相干入射光被完美吸收和散射，只有非相干。我们还展示了如何PT对称性可以产生在全反射和平衡散射和损失之间的不同偏振的集体模式。
Parity-Time (PT) symmetry has become an important concept in the design of synthetic optical materials, with exotic functionalities such as unidirectional transport and nonreciprocal reflection. At exceptional points, this symmetry is spontaneously broken, and solutions transition from those with conserved intensity to exponential growth or decay. Here, we analyze a quantum-photonic surface formed by a single layer of atoms in an array with light mediating strong cooperative many-body interactions. We show how delocalized collective excitation eigenmodes can exhibit an effective PT symmetry and nonexponential decay. This effective symmetry is achieved in a passive system without gain by balancing the scattering of a bright mode with the loss from a subradiant dark mode. These modes coalesce at exceptional points, evidenced by the emergence of coherent perfect absorption where coherent incoming light is perfectly absorbed and scattered only incoherently. We also show how PT symmetry can be generated in total reflection and by balancing scattering and loss between different polarizations of collective modes.