Scattering exceptional point in the visible

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.

Automated summary

This paper reports a universal paradigm for achieving high-efficiency exceptional points (EPs) in the visible range by leveraging interlayer loss to control the interplay between a lossy structure and scattering lightwaves. A bilayer framework is demonstrated to efficiently reflect and absorb incident light, opening up possibilities for nanoscale devices and EP physics.