Presentation Information
[10p-E217-18]Optical Response of Surface-Immobilized Gold Nanospheres on Finite-Thickness Gold Films
〇Tong Zhou1, Maria Vanessa Balois-Oguchi1, Kotaro Kajikawa1 (1.Science Tokyo, Eng.)
Keywords:
localized surface plasmon resonance,gold nanoparticle on film,effective medium approximation
We present a fast analytical method, within the quasi-static approximation, for the optical response of surface-immobilized gold nanospheres (SIGNs) on finite-thickness gold films. The gold film and glass substrate are replaced by a single semi-infinite effective medium whose permittivity is obtained by matching the multilayer reflection coefficient, after which the established truncated-sphere multipole solution is applied. For 50-nm SIGNs, the gap-mode absorption peak red-shifts and weakens as the film is thinned, and the analytical spectra agree with finite-element (COMSOL) calculations and with measured p-polarized absorption spectra. Requiring far less computation than full numerical methods, the approach enables broad parameter studies and can be readily extended to SERS and nonlinear optics.