Fano resonance induced by mode coupling in all-dielectric nanorod array

We propose an efficient way to realize Fano-type resonances at optical frequencies based on a low-loss dielectric nanorod array. An ultrahigh Q factor (larger than 10000) is numerically demonstrated, which is attributed to the mode interference between the broadband Fabry-Perot (FP) resonance and the narrowband guided mode stemming from coupled quadrupoles. A wide gap region for field enhancement is formed between adjacent rods, making such a structure an ideal platform for related applications such as biological sensing and nonlinear devices. (C) 2014 The Japan Society of Applied Physics