RESUMO
The ability to infer near-field scattering properties from far-field measurements is of paramount importance in nano-optics. Recently we derived an approximate formula for predicting the frequency shift between near- and far-field intensity peaks in the case of a dielectric sphere. In this work we demonstrate that almost an identical formula can be used to predict the resonance shift of a dielectric cylinder and a perfectly conducting cylinder. We find the redshift of the resonance peak of the perfect electric conducting cylinder to be approximately 2 orders of magnitude greater than for the dielectric cylinder. The errors in our approximate analytic formula for predicting the redshift are approximately only twice as great. Furthermore, we apply the redshift formula to a silicon cylinder and discuss its magneto-dielectric properties, which may be of interest in design of metamaterials.
RESUMO
The near-field electromagnetic scattering intensity resonances are redshifted in frequency with respect to their far-field counterparts. We derive simple, approximate, analytical formulas for this shift in the case of a plane wave interacting with a dielectric sphere. Numerical results comparing the approximate formulas to the numerically exact solutions show that the two are in good agreement. We also consider the Rayleigh limit of the formulas to gain more insight into the phenomenon.
RESUMO
The nonoxidizing catalytic noble metal rhodium is introduced for ultraviolet plasmonics. Planar tripods of 8 nm Rh nanoparticles, synthesized by a modified polyol reduction method, have a calculated local surface plasmon resonance near 330 nm. By attaching p-aminothiophenol, local field-enhanced Raman spectra and accelerated photodamage were observed under near-resonant ultraviolet illumination, while charge transfer simultaneously increased fluorescence for up to 13 min. The combined local field enhancement and charge transfer demonstrate essential steps toward plasmonically enhanced ultraviolet photocatalysis.
