Scattering exceptional point in the visible
Tao He, Zhanyi Zhang, Jingyuan Zhu, Yuzhi Shi, Zhipeng Li, Heng Wei, Zeyong Wei, Yong Li, Zhanshan Wang, Cheng‐Wei Qiu, Xinbin Cheng
Abstract
Abstract Exceptional point (EP) is a special degeneracy of non-Hermitian systems. One-dimensional transmission systems operating at EPs are widely studied and applied to chiral conversion and sensing. Lately, two-dimensional systems at EPs have been exploited for their exotic scattering features, yet so far been limited to only the non-visible waveband. Here, we report a universal paradigm for achieving a high-efficiency EP in the visible by leveraging interlayer loss to accurately control the interplay between the lossy structure and scattering lightwaves. A bilayer framework is demonstrated to reflect back the incident light from the left side ( | r −1 | >0.999) and absorb the incident light from the right side ( | r +1 | < 10 –4 ). As a proof of concept, a bilayer metasurface is demonstrated to reflect and absorb the incident light with experimental efficiencies of 88% and 85%, respectively, at 532 nm. Our results open the way for a new class of nanoscale devices and power up new opportunities for EP physics.