Web Release Date: November 7,
Surface Plasmon Resonance Sensitivity of Metal Nanostructures: Physical Basis and Universal Scaling in Metal Nanoshells
Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
Received: September 11, 2007
In Final Form: October 18, 2007
Abstract:
In this letter, we show using extended Mie theory simulations that the sensitivity of the surface plasmon resonance (SPR) of a dielectric core-metal nanoshell increases near-exponentially as the ratio of the shell thickness-to-core radius is decreased. The plasmon sensitivity thus shows the same universal scaling behavior established recently for plasmon coupling in metal nanoshells and that in metal nanoparticle pairs. From these observations, we propose that the sensitivity is determined by the ease of surface polarization of the electrons in the nanostructure by the light. This can be used as a generalized physical principle for designing plasmonic nanostructures for effective SPR chemical and biological sensing.
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