Study paves the way for new class of nanoscale devices, new opportunities in photonics

https://phys.org/news/2023-09-paves-class-nanoscale-devices-opportunities.html

"high-efficiency metasurface optical exceptional points (EPs) leveraging interplay between lossy structure and scattering lightwaves... bilayer metasurface TiO2 metagrating and Si subwavelength grating... metagrating in upper layer directional regulated lightwave, and lossy subwavelength grating lower layer adjustable absorption... light from left reflected to incident path. When from right little retroreflection... reflect and absorb incident light efficiencies 88% and 85% at 532 nm... optical sensing, integrated optics"