Enhanced light diffraction from a double-layer microsphere lattice

Abstract

Anomalously strong diffraction, whose efficiency is as high as 55%, has been observed from a double-layer microsphere lattice. The enhancement is due to the specular resonance scattering from two spheres in contact, each belonging to the top and bottom layers of the double-layer, respectively. The system thus works as a single layer two-dimensional (2D) lattice of bispheres. No enhancement is observed from a single-layer lattice nor from triple-layer lattice. It functions as a “blazed” transmission grating with 2D spectral dispersion compared with the one-dimensional dispersion in ordinary linear gratings.