Eur. Phys. J. B (2015) 88: 144
https://doi.org/10.1140/epjb/e2015-60007-8

Regular Article

Realizing Fano-like resonance in a one terminal closed T-shaped waveguide

¹ Key Lab for Micro-Nano Physics and Technology, School of Physics and Electronics, Hunan University, Changsha 410082, P.R. China
² Department of Electrical and Information Engineering, University of Electronic Science and Technology of China, Chengdu 610054, P.R. China

^a e-mail: xfli@hnu.edu.cn
^b e-mail: llwang@hnu.edu.cn

Received: 5 January 2015
Received in final form: 29 April 2015
Published online: 3 June 2015

Abstract

We obtain a special Fano-like resonance in a semi-closed T-shaped waveguide with nanodisk resonator, in which only two bright plasmon modes work. It is found that the transmission spectrum occurs a red-shift by increasing either length of the nanoslot or radius of the nanodisk. Moreover, when the length of the nanoslot and radius of the nanodisk reach to some particular values at the same time, the transmission spectrum will show an inverse line shape or the Fano-like resonance will disappear. Meanwhile, the classical figure of merit obtained by calculation is as high as 199 with a sizable classical sensitivity value reaches to 1114 nm/RIU. The generalized figure of merit also comes to an impressive value of 7961 nm/RIU. Besides, it is worth noting that the maximums of these two kinds of FOM lie in the dips of different linewidth, which can be utilized in diverse types of sensors. Our studies further provide a guidance for fabricating planar devices in near-infrared region.