EFFECT OF A SILICON TIP ON ABSORPTION CROSS SECTION, FIELD ENHANCEMENT, AND LOCALIZED SURFACE PLASMON RESONANCE OF DIFFERENT SIZED GOLD NANOPARTICLES UNDER EVANESCENT WAVE ILLUMINATION

• Main Author: Huda, Gazi Mostafa
• Format: Others
• Published: UKnowledge 2011
• Subjects: Particles; mie theory; total internal reflection; plasmonics; computational electromagnetic methods; Electrical and Computer Engineering
• Online Access: http://uknowledge.uky.edu/gradschool_theses/114; http://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1117&context=gradschool_theses

We have numerically investigated the influence of a nanoscale silicon tip in proximity to an illuminated gold nanoparticle. We describe how the position of the high-permittivity tip and the size of a nanoparticle impact the absorption, peak electric field and surface plasmon resonance wavelength under different illumination conditions. We detail the finite element method (FEM) approach we have used for this, whereby we specify a volume excitation field analytically and calculate the difference between this source field and the total field (i.e., scattered-field formulation). We show that a nanoscale tip can locally enhance the absorption of the particle as well as the peak electric field at length scales far smaller than the wavelength of the incident light.