Soheila Mashhadi

Collective plasmonic oscillations in gold nanostrips arrays

Excitation of collective plasmonic modes and their effect on optical behavior are experimentally and theoretically studied in 1D arrays of gold nanostrips in comparison with continuous gold films with periodically modulated profile. In strips, the angular dependence of the reflectivity demonstrates a peak at the resonance condition as opposed to a dip observed in continuous sine wave gratings. In addition, an extremely narrow feature in the reflection is observed in strips and tentatively ascribed to the bright Wood-Rayleigh anomaly. Theoretical calculations based on the combined transfer-matrix coupled-wave analysis and coordinate transformation method are shown to fit the experimental angular and spectral behavior of the plasmonic resonances. The effects are also discussed in terms of a simple equivalent circuit model.

Probing and mapping optical fields in Si disk arrays with Eu 3

We experimentally study enhancement of spontaneous emission of Eu3+ at the magnetic dipole transition by Mie-resonances in silicon nanodisks and estimate the spectral branching ratio as the function of the nanodisk radius.

Collective plasmonic oscillations in nanostrips arrays and continuous sine-wave gratings. Comparative study

Gold nanostrip arrays exhibit collective plasmonic oscillations analogous to surface plasmon-polaritons in continuous films with a spatially modulated profile. Similarities and differences in optical behavior of continuous and discontinuous systems are studied experimentally and theoretically.

Probing and mapping plasmonic systems by spectroscopic methods(Conference Presentation)

Rare earth ions having both electric and magnetic dipole transitions in emission spectra can be used as local probe to provide information on degree of modification and local distribution of optical electric and magnetic fields in plasmonic systems. In our research, we use highly luminescent organic systems with Eu3+ to study and analyze modification of magnetic and electric dipoles emission in different environment, including systems having plasmonic electric resonance or magnetic resonance in the range of Eu3+ emission, and flat metal. Experimental setup based on selective detection of the particular transition was built and used for probing and mapping of electric and magnetic fields in plasmonic systems and metasurfaces. The method developed can find applications in characterization of plasmonic systems and metamaterials, and engineering of emission properties of rare earth ions and other emitters.