Plasmonics

M. Kreiter

Metal structures with typical dimension of the wavelength of light and below support optical resonances, the particle plasmons. These resonances are accompanied by an increased absorption and scattering of the particles and by a sometimes significant increase in the electromagnetic field in the proximity to the particles.

left : Preparation scheme for metal crescents right : Gold crescents of different shape and size

A simple routine for the production for highly versatile crescent-shaped metal objects was developed[1]. These structures support several strong plasmonic resonances in the visible and near infrared which can be tuned in wavelength by adjusting the crescents geometry. As a prominent feature, sharp tips are expected to render these structures high-performance optical antennae with a strong near-field enhancement which could be proven by photoemission electron microscopy [2]. Applications of such antennae range from enhanced light collection and generation to optical chemo- and biosensing in sub-diffraction volumes.

[1] J. Shumaker-Parry, H. Rochholz, M. Kreiter. Fabrication of crescent-shaped optical antennae Advanced Materials, in print
[2] M. Cinchetti, A. Gloskovskii, S. A. Nepjiko, G. Schönhense, H. Rochholz, M. Kreiter. Photoemission Electron Microscopy as a Tool for the Investigation of Optical Near Fields, Phys. Rev. Lett. 95, 047601 (2005)