Phys.org April 21, 2022
Waves entering a spatially uniform lossy medium typically undergo exponential intensity decay, arising from either the energy loss or the evanescent penetration during reflection. A team of researchers in the US (NIST, University of Maryland, Texas Tech University, Carnegie Mellon University) proposed and demonstrated exponential decay free wave propagation in a purely lossy medium. They observed up to 400-wave deep polynomial wave propagation accompanied by a uniformly distributed energy loss across a nanostructured photonic slab waveguide with exceptional points. Using coupled-mode theory and fully vectorial electromagnetic simulations they predicted deep wave penetration manifesting spatially constant radiation losses through the entire structured waveguide region regardless of its length. The work has applications in generating large, uniform and surface-normal free-space plane waves directly from dispersion-engineered photonic chip surfaces…read more. TECHNICAL ARTICLE
Experimental apparatus. Credit: Nature Nanotechnology (2022)Â