Optical manipulation and nano plasmonics with applications in condensed and soft matter

Prof. E. Di Fabrizio
Laboratorio Nazionale TASC, Area Science Park, Basovizza (TS)
BIONEM Laboratory, University of Magna Graecia, Catanzaro

ABSTRACT: The lecture will cover two main subjects: optical manipulation and nano plasmonics.
1) The interest in using optical forces in soft matter, biology and medicine has increased enormously. Today, optical manipulations cover different fields of applications and, very quickly, a worldwide community is developing techniques and new scientific fields. New results on optical tweezing based on optical fibers will be presented. This application is particularly promising for in vivo medicine for future application in in situ drug delivery, where the fiber can be used as microprobe for both imaging and trapping.
2) In recent years, there was an increasing interest on design and fabrication of nanostructures devoted to photonic applications such as photonic crystals fabrication [1], spectroscopy analysis, detection of single molecules and fundamental studies on well confined electromagnetic field. Different materials, fabrication techniques and applications were especially devoted to the use of plasmonic enhancement to the study of molecules of biological interest. The main task was the control the enhancement of the local electrical field, in order to overcome the low scattering cross section of the Raman effect, when single molecule has to be detected. In this section we present the fabrication of a novel plasmonic nanostructure for Surface Enhanced Raman Scattering for single molecule detection. High sensitivity measurements of a few tens of molecules will be presented. The choice of nanolithography as fabrication techniques is due to the fact that it is now necessary to investigate, in a controllable and reproducible way the effect of 3D geometry on the generation of plasmon-polaritons on such material and devices. The structures were tested optically with different set up, and we found significant improvement in the spectra quality and in the detection sensitivity, down to a few tens of molecules.