Gold Prisms for Surface Enhanced Spectroscopy - SPP7 Abstract Submission Form

Leonid Dolgov Laboratory of laser spectroscopy, Institute of Physics, University of Tartu, Tartu, Estonia Victorio Estrela-Llopis Laboratory of biocolloid physics and glyconanosynthesis, Ovcharenko Institute of biocolloidal Chemistry, National Academy of Sciences of Ukraine, Kyiv, Ukraine Olena Fesenko Department of Physics of Biological systems, Institute of Physics, National Academy of Sciences of Ukraine, Kyiv, Ukraine Taavi Repan Laboratory of laser spectroscopy, Institute of Physics, University of Tartu, Tartu, Estonia Viktoria Sorokina Laboratory of laser spectroscopy, Institute of Physics, University of Tartu, Tartu, Estonia Valter Kiisk Laboratory of laser spectroscopy, Institute of Physics, University of Tartu, Tartu, Estonia Ilmo Sildos Laboratory of laser spectroscopy, Institute of Physics, University of Tartu, Tartu, Estonia Sergei Kopanchuk Bioorganic Chemistry, Institute of Chemistry, University of Tartu, Tartu, Estonia

Noble metal nanoparticles with anisotropic shapes attract increasingly more scientific and applied attention. To a large extent it is due to the ability of design their optical properties by selection of proper shape and size. Since the surface electrons in noble metal nanoparticles have size- and shape-dependent resonant frequencies and at the same time can couple with the incident light, the idea of using them as an antennas enhancing optical signals from the target molecules looks fruitful. This purpose presumes extensive search for new methods for the preparation of anisotropic particles as well as investigation of light-induced electric fields in them to find the most effective way for the optical signal enhancement.

Proposed gold micro- and nanocrystals were grown in water solution of chloroauric acid with polysaccharides as reducing and stabilizing agent [1]. The nanothickness particles have mostly the shape of a triangular prism ranging from nanometers to 5-10 micrometers in size. As such they look prospective for the enhancement of optical signals from organic and inorganic probes. The particles were washed carefully to minimize the influence of polysaccharides.

The dark field microscopy of particles deposited on the titania film doped by Sm3+ rare earth ions revealed a colored light scattering spots, which were associated with the plasmonically active nanosized part of particles. The same area of sample demonstrated locally enhanced Sm3+ fluorescence in the vicinity of plasmonically active gold particles under the ultraviolet excitation. Preliminary theoretical simulation at the microsized, but nanothickness gold prisms, in the case when laser beam direction is perpendicular to the nanoprizm’s plane, showed enhanced light induced intensity of electric field along the lateral faces of the prism, which corresponds to the experimentally detected enhanced light scattering from there. This bring us to the conclusion that plasmon-polariton waves propagate along the lateral faces in case of microprisms, while localized plasmons are situated in the nanosized prisms. This work was supported by ILSES project no. 612620, NATO SPS project NUKR.SFPP 984702, Nanotwinning FP7 project (ID 294952) and European Regional Development Fund project TK114.

[1] Estrela-Llopis V. et. al. Ch.12 in Nano-Science, Taylor&Francis (2010).

leonid.dolgov@ut.ee