Igor A. Budashov

Light localization and SERS in tip-shaped silicon metasurface

Optical properties of two dimensional periodic system of the silicon micro-cones are investigated. The metasurface, composed of the silicon tips, shows enhancement of the local optical field. Finite element computer simulations as well as real experiment reveal anomalous optical response of the dielectric metasurface due to excitation of the dielectric resonances. Various electromagnetic resonances are considered in the dielectric cone. The metal-dielectric resonances, which are excited between metal nanoparticles and dielectric cones, are also considered. The resonance local electric field can be much larger than the field in the usual surface plasmon resonances. To investigate local electric field the signal molecules are deposited on the metal nanoparticles. We demonstrate enhancement of the electromagnetic field and Raman signal from the complex of DTNB acid molecules and gold nanoparticles, which are distributed over the metasurface. The metasurfaces composed from the dielectric resonators can have quasi-continuous spectrum and serve as an efficient SERS substrates.

Enhancement of SERS signal using new material based on cerium dioxide facet dielectric films

In this paper, we investigate the potential of facet structures of cerium dioxide for the purpose of increasing the intensity of the surface enhancement Raman scattering (SERS) signal. During the studies, a new metamaterial is developed. The metamaterial is based on facet cerium dioxide films and plasmonic nanoparticles that are immobilized on its surface. The new metamaterial provides an additional SERS signal amplification factor of more than 200. Thus developed material offers the prospect of increasing the sensitivity and selectivity of biochemical and immunological analysis.

Giant field fluctuations in dielectric metamaterial and Raman sensor

New dielectric metamaterial based on the Bragg filter comprising ten dielectric bilayers was investigated. Each bilayer is the thin films of silicone dioxide (SiO2) and another film of zirconium dioxide (ZrO2). The surface of the multilayer film is profiled. It has a form of periodic system of rectangles separated by the open gaps. We use the computer simulation as well as analytical solution to find the reflectance of the multilayer as a function of the wavelength and electromagnetic (em) field distribution. The multilayer system reveals the enhancement of em fields at the surface. The considered Bragg filter was modified by Raman-active structure made of gold nanoparticles with chemically attached 3,3-thio-bis(6- nitrobenzoic acid) - (TNB). The high Surface Enhanced Raman Scattering (SERS) signal was detected.

Surface dielectric resonance and giant enhancement of Raman scattering

We propose multiple resonances in the thin profiled dielectric films. The excitation of the dielectric resonances results in giant electric and magnetic field fluctuations. We observe dielectric enhanced Raman scattering in the investigated dielectric films.

Sensors based on dielectric metamaterials

The possibility of amplification of local electric fields on the surface of thin dielectric films of complex structure is considered. Amplification of the optical field enables an increase in the intensity of the Raman scattering signal and provides broad opportunities for the development of novel biochemical sensors.