Visible perfect reflectors realized with all-dielectric metasurface

Highrefractive index dielectric material with negligible absorption loss can offer strong confinement of light, providing a potential alternative to plasmonic materials at optical frequencies. Here, we demonstrate perfect reflectors with unit reflection (over 99%), by utilizing the Mie resonances of high index amorphous titanium dioxide (alpha TiO2) metasurface arrays. Full-wave simulation and realistic optical constants analysis show that, these perfect reflectors exhibiting (magnetic or electric) dipole resonance can produce a perfect magnetic conductor (PMC) or a perfect electric conductor (PEC). Specifically, such a PMC mirror does not reverse the phase (phi, = 0) of the reflected electric field, resulting in the standing wave close to the mirror has an enhanced maxima field. Therefore, an object placed closely to the surface of a PMC will have a significant stronger interaction with electric field than that placed to a PEC. This unique PMC metasurface serving as back reflectors may enhance light absorption in devices with thin active films, such as solar cells, light-emitting diodes and biosensor devices. (C) 2017 Elsevier B.V. All rights reserved.