Related Experiment Video
Updated: Jun 8, 2026
11:44
Surface Enhanced Raman Spectroscopy Detection of Biomolecules Using EBL Fabricated Nanostructured Substrates
Published on: March 20, 2015
Long range surface plasmons on asymmetric suspended thin film structures for biosensing applications
Qiao Min1, Chengkun Chen, Pierre Berini
1Dept. of Elec. and Comp. Eng., University of Victoria, 3800 Finnerty Rd, Victoria, BC, V8P 5C2, Canada.
Optics Express
|October 14, 2010
Summary
This study demonstrates long-range surface plasmons (LRSPs) in an asymmetric thin film waveguide. The asymmetric design enhances biosensor performance, offering a promising platform for aqueous solution sensing applications.
Area of Science:
- Plasmonics
- Nanophotonics
- Thin Film Optics
Background:
- Long-range surface plasmons (LRSPs) are crucial for sensing applications.
- Traditional LRSP structures often require specific substrate matching, limiting their use with aqueous solutions.
Purpose of the Study:
- To investigate LRSP support in a physically asymmetric thin film structure.
- To develop an analytic formulation for designing such structures.
- To compare the performance of asymmetric versus symmetric LRSP waveguides for biosensing.
Main Methods:
- Derivation of a 1D analytic formulation for LRSP guiding.
- Transfer matrix calculations for quantitative analysis.
- Finite difference method for 2D confinement analysis.
Main Results:
- LRSPs are supported in a suspended asymmetric thin film waveguide (e.g., H2O-Au-SiO2-air).
- The analytic formulation accurately predicts waveguide parameters.
- The asymmetric structure shows improved biosensor performance metrics compared to symmetric designs, despite higher optical losses.
Conclusions:
- Asymmetric thin film structures offer a viable platform for LRSP guiding.
- The proposed design overcomes limitations of substrate matching for aqueous sensing.
- This work presents a promising approach for developing advanced biosensors.
