Excitation of surface plasmons using tilted planar-waveguide Bragg gratings

• Main Authors: Holmes, C. (Author), Daly, K.R (Author), Sparrow, I.J.G (Author), Gates, J.C (Author), D'Alessandro, G. (Author), Smith, P.G.R (Author)
• Format: Article
• Language: English
• Published: 2011-09.
• Subjects: Article
• Online Access: Get fulltext

We present a planar integrated optical surface plasmon refractometer. The fabricated device operates by grating-matched coupling between a core waveguide mode and a set of hybrid plasmon-dielectric modes of a much wider integrated structure. The constructed device incorporates a 50 nm thin gold layer that separates a tilted planar-waveguide Bragg grating and a liquid analyte. It is demonstrated that polarization dependent plasmon anomalies occur in the transmission spectra of the device, which are understood using a numerical Cauchy integral mode solving approach. Sensitivities in this planar integrated device are comparable to existing fiber based plasmonic sensors, but with the advantages of planar integration and microfluidic adaptation.