Open AccessRefractive-index sensor based on long-range surface plasmon mode excitation with longperiod waveguide grating
Author(s) -
Q. Liu,
Kin Seng Chiang
Publication year - 2009
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.17.007933
Subject(s) - optics , waveguide , materials science , refractive index , surface plasmon , grating , radiation mode , surface plasmon resonance , surface plasmon polariton , coupled mode theory , prism , localized surface plasmon , optoelectronics , plasmon , single mode optical fiber , optical fiber , physics , nanoparticle , nanotechnology
We propose a refractive-index sensor that operates on the principle of exciting the long-range surface plasmon mode of a metal-coated waveguide with a long-period grating formed in the waveguide, where the wavelength at which the mode excitation occurs serves as a measure of the refractive index of the external medium. We analyze the sensor with a coupled-mode theory and highlight the effects of the waveguide parameters on the loss of the surface plasmon mode and the performance of the sensor. Our results show that the sensor can provide a sharp resonance for high precision measurements and a high sensitivity comparable to that of an optimized bulk prism-based surface plasmon sensor. Our sensor also offers much flexibility in the choice of waveguide parameters for different applications.