RESUMEN
We measured the transmission spectra of an array of split-ring resonators (SRRs) up to 10 terahertz for parallel and perpendicular polarizations. Calculations of the lattice and plasmon mode dispersion relations, in combination with electromagnetic simulations, confirm the presence of multiple higher-order lattice and plasmon modes. We modify the quality factor of higher-order plasmon resonances by modulating the lattice-plasmon mode coupling via changes in the period of the array. We also propose single frequency switches and a broadband dual-state amplitude modulator based on structured illumination that actively modifies the period of the SRR array.
RESUMEN
Selenoproteins play an important role in the human body by accomplishing essential biological functions like oxido-reductions, antioxidant defense, thyroid hormone metabolism and immune response; therefore, the possibility to synthesize selenium nanoparticles free of any contaminants is exciting for future nano-medical applications. This paper reports the first synthesis of selenium nanoparticles by femtosecond pulsed laser ablation in de-ionized water. Those pure nanoparticles have been successfully used to inhibit the formation of Candida albicans biofilms. Advanced electron microscopy images showed that selenium nanoparticles easily adhere on the biofilm, then penetrate into the pathogen, and consequently damage the cell structure by substituting with sulfur. 50% inhibition of Candida albicans biofilm was obtained at only 25 ppm. Finally, the two physical parameters proved to affect strongly the viability of Candida albicans are the crystallinity and particle size.
