Enhanced Spectral Sensing by Electromagnetic Coupling with Localized Surface Plasmons on Subwavelength Structures

Document Type

Article

Publication Date

3-2010

Abstract

Existing sensor platforms have limited sensitivity, specificity, and portability. With a new algorithm for the coupled dipole approximation of Maxwell’s equations, we examine nearand far-field features of electromagnetism (EM) coupled with localized surface plasmons on subwavelength, solid-state nanoparticle (NP) structures measured using spectroscopy, microscopy, and calorimetry. Near-field extinction efficiency, blue/redshifts, and full-width at half-maximum are optimized using a new “bottom-up” NP assembly method that tunes particle size and spacing to enhance sensitivity and produce molecule-specific ≥ tenfold surface-enhanced Raman spectroscopy enhancements. Far-field plasmon–photon resonances are identified, which offer ≥10⁶-fold higher sensitivity. Solid-state NP structures increase stability, reduce power consumption, and improve response time and optothermal transduction up to tenfold for better portability and throughput relative to aggregation-prone NP suspensions. Sample rate is increased ≥ tenfold by inducing transverse hydrodynamic diffusion adjacent to sensor interfaces. These results guide development of next-generation chemical and biological sensors based on EM-coupled UV, Raman, or terahertz modes that improve sensitivity, biospecificity, stability, and portability to distinguish biological molecules and species at high throughputs.

Department

Physics and Astronomy

Publication Title

IEEE Sensors Journal

DOI

10.1109/JSEN.2009.2038451

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