Coherent perfect absorption at an exceptional point
Coherent perfect absorption at an exceptional point
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DOI：
10.1126/science.abj1028
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发表时间：
2021-09-10
期刊：
影响因子：
56.9
通讯作者：
Yang, Lan
中科院分区：
文献类型：
--
作者：
Wang, Changqing;Sweeney, William R.;Yang, Lan
最近，在光子学、声学和电子学中，已经观察到异常点，即开波系统的简并。它们主要被实现为共振的简并;然而，与波的吸收相关的简并可以表现出独特而有趣的物理特征。在这里，我们证明了这样的吸收例外点的工程退化的耗散光学微腔的吸收光谱。我们实验区分的条件，实现吸收例外点与共振例外点。此外，当光学损耗被调谐以在吸收例外点处实现完美吸收时，我们观察到其特征，即吸收光谱中的异常加宽的线形。吸收例外点的独特散射性质为非厄米简并的基础研究和应用创造了机会。
Recently, exceptional points, a degeneracy of open wave systems, have been observed in photonics, acoustics, and electronics. They have mainly been realized as a degeneracy of resonances; however, a degeneracy associated with the absorption of waves can exhibit distinct and interesting physical features. Here, we demonstrate such an absorbing exceptional point by engineering degeneracies in the absorption spectrum of dissipative optical microcavities. We experimentally distinguished the conditions to realize an absorbing exceptional point versus a resonant exceptional point. Furthermore, when the optical loss was tuned to achieve perfect absorption at an absorbing exceptional point, we observed its signature, an anomalously broadened line shape in the absorption spectrum. The distinct scattering properties of the absorbing exceptional point create opportunities for both fundamental study and applications of non-Hermitian degeneracies.