TITLE:
Detecting High-Refractive-Index Media Using Surface Plasmon Sensor with One-Dimensional Metal Diffraction Grating
AUTHORS:
Atsushi Motogaito, Shinya Mito, Hideto Miyake, Kazumasa Hiramatsu
KEYWORDS:
Surface Plasmon Resonance, High-Refractive-Index Media, Diffraction Grating, Extraordinary Transmission
JOURNAL NAME:
Optics and Photonics Journal,
Vol.6 No.7,
July
18,
2016
ABSTRACT: We experimentally
detect high-refractive-index media (n >
1.5) using a surface plasmon resonance (SPR) sensor with a diffraction grating.
While SPR sensors are generally based on the attenuated total reflection method
using metal films, here, we focus on a method using a diffraction grating,
which can detect relatively higher refractive-index media and is suitable for
device miniaturization. In this study, we used the rigorous coupled-wave
analysis method to simulate the dependence of the reflectance on an incident
angle for media with refractive index values up to 1.700. In the experiment, a
medium (n = 1.660 - 1.700) was
successfully detected using this grating. Under the conditions of the grating
(period: 600 nm, Au thickness: 40 nm) using a red laser (λ: 635 nm), a sharp decline in the reflectance and a rise in the
transmittance at certain angles were confirmed, demonstrating the extraordinary
transmission enabled by SPR. Because excitation angles changed with changes in
the refractive index, we concluded that this method can be applied to sensors
that detect high-refractive-index media.