Sensitivity of surface plasmon resonance sensors based on metallic columnar thin films in the spectral and angular interrogations

Surface Plasmon Resonance (SPR) from metallic Columnar Thin Films (CTFs) of porosity as high as 0.5 was experimentally and theoretically investigated. The CTF layers were prepared by the Glancing Angle Deposition (GLAD) method. The SPR features were investigated in both the angular and the spectral...

Full description

Saved in:
Bibliographic Details
Published in:Sensors and actuators. B, Chemical Chemical, 2011-11, Vol.159 (1), p.201-212
Main Authors: Shalabney, Atef, Khare, C., Rauschenbach, B., Abdulhalim, I.
Format: Article
Language:English
Subjects:
composite materials
Dyadics
Interrogation
Mathematical analysis
nanomaterials
Nanostructure
Optical biosensors
porosity
refractive index
Sculptured thin films
Sensitivity enhancement
Sensors
Spectra
Surface plasmon resonance
Thin films
Wavelengths
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Surface Plasmon Resonance (SPR) from metallic Columnar Thin Films (CTFs) of porosity as high as 0.5 was experimentally and theoretically investigated. The CTF layers were prepared by the Glancing Angle Deposition (GLAD) method. The SPR features were investigated in both the angular and the spectral modes. In the angular interrogation, increasing the porosity causes broadening to the dip width, shift to larger resonance angles, and increase of the sensitivity to analyte refractive index (RI) changes by about threefold compared with closed metal films. In the spectral interrogation, on the other hand, the resonance wavelengths are red-shifted for porous films; hence their spectral sensitivities are higher than those of closed films under the same experimental conditions. Nevertheless, the sensitivity behavior versus the resonance wavelength is similar to that of SPR sensors based on dense film layers. The shapes of the nanostructures constituting the CTF are described as ellipsoidal inclusions in which the effective permittivity dyadic of the composite material is calculated using the Bruggeman formalism with exact depolarization dyadics. The correlation between the sensitivity enhancement and the electromagnetic field intensity at the interface between the metallic film and the analyte was examined. Electromagnetic fields analyses were performed using the general 4 × 4 propagation matrices of general homogenous biaxial layers.
ISSN:0925-4005
1873-3077
DOI:10.1016/j.snb.2011.06.072