December 22, 2010 Wednesday 15:30
Kürşat Şendur, Sabancı University
Strong Dichroism and Birefringence of Subwavelength Apertures and Nanoantennas

The interaction of photons with metallic nanoparticles and nanoantennas is important to a number of emerging nanotechnology applications due to the large enhancement and tight localization of electromagnetic fields in the vicinity of nanoparticles. This interaction has existing and emerging applications at the nanoscale, including near-field scanning optical microscopy, high-density data storage, and bio-chemical sensing. Although there has been much effort to understand the effects of various parameters on the plasmon resonances of nanoparticles, the polarization aspects of this interaction has largely been omitted in the context of particle plasmons. Recently, there has been growing interest in obtaining optical spots with various polarizations using plasmonic nano-antennas and subwavelength apertures. Although, plasmonic nano-antennas and subwavelength apertures have been investigated for potential utilization as nano-optical polarization elements, two crucial polarization related properties, birefringence and dichroism, have not been investigated. In the first part of this study, we examine the birefringence and dichroism of plasmonic nanoantennas and subwavelength apertures. The underlying reasons of birefringent and dichroic behaviour are provided. In the second part, metallic nano-antennas are investigated to achieve localized heating in the sample which requires high transmission efficiency. Mechanisms that affect the interaction of the nano-antenna and the metallic layer are investigated. The results show that localized heating in a near-field sample is achieved via the radiative energy transfer in the vicinity of a nano-antenna.