Open AccessThe observation of super-long range surface plasmon polaritons modes and its application as sensory devices
Author(s) -
X. L. Zhang,
Jun-Feng Song,
G. Q. Lo,
DimLee Kwong
Publication year - 2010
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.18.022462
Subject(s) - refractive index , materials science , optics , surface plasmon polariton , surface plasmon , slab , dispersion (optics) , polariton , silicon , plasmon , optoelectronics , physics , geophysics
In this communication, we will describe one unique phenomenon and the potential application of it. In this work, the dispersion relation of an air-silver-silicon-silver-fluid (air-Ag-Si-Ag-fluid) five-layer slab is analyzed theoretically, in which the super-long range surface plasmon polaritons (SPP) modes, whose energy penetrates deeply into the fluid, are found with their losses being extremely small and sensitive to the change of the fluid refractive index when operating near their interspace cut-off regions, where the dispersion curves are non-continuous. By applying this phenomenon in detecting the fluid refractive index change, a SPP sensor based on intensity measurement is proposed. It is a waveguide structure with an Ag-Si-Ag slab together with a flow cell filled with the detecting fluid. It is found that a large scale of linear detection (e.g., 0.08, for 1550 nm ~1.33 to 1.41) with high resolution (e.g., 7.9 × 10(-6) Refractive Index Units) can be achieved for a very short device, which is 200 μm.