|AVS 54th International Symposium|
|Plasmonics Topical Conference||Tuesday Sessions|
|Session:||Plasmon-mediated Sensing and Biosensing|
|Presenter:||A.A. Lazarides, Duke University|
|Authors:||M.M. Miller, Duke University
S. Chen, Duke University
A. Chilkoti, Duke University
A.A. Lazarides, Duke University
|Correspondent:||Click to Email|
The plasmon bands of metal nanoparticles are known to be sensitive to the refractive index of the environment. The magnitude of the sensitivities vary widely for resonances supported by particles of various shape, size, and composition. Through spectral simulation, however, it has been shown that the resonant frequency of particles suspended in a medium have sensitivities to refractive index of the medium that are determined with high accuracy by the plasmon frequency and the dielectric properties of the particle and medium, when the particle is composed of a single component and of modest phase volume.1,2 Immobilized particles, in contrast, display sensitivities to the exchangeable component of their media that are reduced relative to those of suspended particles and expected to be dependent upon the nature and localization of the mode and its interaction with the substrate. Here, we report measurements and simulations of the refractive index sensitivities of a family of gold nanorods immobilized on glass, and a comparison of the immobilized particle sensitivities with the generic sensitivities of plasmons supported by suspended particles. The refractive index sensitivities of the immobilized rods are found to be well predicted by a band location dependent sensitivity function reduced from the generic solution phase sensitivity function by a constant scale factor derived from comparison of simulation and theory. The applicability of the result to immobilized particles of other shapes, sizes, and compositions will be discussed within the framework of sensitivity theory.
1 Miller, M. M.; Lazarides, A. A. “Sensitivity of Metal Nanoparticle Surface Plasmon Resonance to the Dielectric Environment” J. Phys. Chem. B 2005, 109, 21556-21565
2 Miller, M. M.; Lazarides, A. A. “Sensitivity of Metal Nanoparticle Plasmon Resonance Band Position to the Dielectric Environment as Observed in Scattering” J. Opt. A: Pure Appl. Opt. 2006, 8, S239-S249.