Quality Factor of a Nanobowtie Antenna

Author

Ni, Chi-Yu Adrian ; Chang, Shu-Wei ; Shun Lien Chuang ; Schuck, P. James

Author_Institution

Dept. of Electr. & Comput. Eng., Univ. of Illinois at Urbana-Champaign, Urbana, IL, USA

Volume

29

Issue

20

fYear

2011

Firstpage

3107

Lastpage

3114

Abstract

We present a rigorous formulation based on the Poynting´s theorem in dispersive and lossy media to calculate the quality factor, material loss, radiation loss, and radiation pattern of an optical nanobowtie antenna using the finite-difference time-domain method. The quality factor obtained from our theory, 8.73, agrees well with the experimental data. Our results show that the radiation loss and material loss are comparable. The material loss mainly originates from the chromium rather than gold even though the nanobowtie antenna mostly consists of gold. In addition, due to the small gap and plasmonic mode confinement, the effective modal volume is ultrasmall [6.36 × 10^-5(λ/n_eff)³], which significantly breaks the diffraction limit.

Keywords

Q-factor; bow-tie antennas; chromium; finite difference time-domain analysis; gold; light diffraction; nanophotonics; optical losses; optical materials; plasmonics; Au; Cr; Poynting theorem; diffraction limit; dispersive media; finite difference time domain method; lossy media; material loss; optical nanobowtie antenna; plasmonic mode confinement; quality factor; radiation loss; radiation pattern; Antennas; Cavity resonators; Chromium; Dispersion; Gold; Materials; Q factor; Bowtie antenna; finite-difference-time-domain method (FDTD); quality factor;

fLanguage

English

Journal_Title

Lightwave Technology, Journal of

Publisher

ieee

ISSN

0733-8724

Type

jour

DOI

10.1109/JLT.2011.2164780

Filename

5983375