Shape dependent full width at half maximum of the absorption band in gold nanorods

The dependence of full width at half maximum (FWHM) of the absorption peak in gold nanorods was investigated as a function of aspect ratio. Numerical calculations based on Drude model and quasi-static theory indicated that, the FWHM of longitudinal absorption peak is wider than that of transverse mode. Further more, with the increasing aspect ratio, the FWHM of longer wavelength absorption peak increasing in a nonlinear way, which is in agreement with the experimental results.