PROJECT TITLE :

Resonant Diffraction Into Symmetry-Prohibited Orders of Metal Gratings

ABSTRACT:

We tend to study, by numerical simulations and experimentally, the resonant diffraction by metal (Ag) gratings within the mid-IR ( $sim ten~mu textm$ ) spectral vary. The excitation of surface plasmon-polaritons facilitates slim-band resonantly enhanced diffraction into symmetry-prohibited diffraction orders. We have a tendency to show that, although the propagation losses for plasmonic modes are greatly reduced at longer wavelengths, the magnitude of the resonant diffraction peak remains limited because of diffraction into other, normally allowed, diffraction orders. The grating depth dependence of the resonant diffraction spectra indicates that with shallower gratings, the $Q$ -issue of the resonance might become as massive as $ten^3$ – $10^4$ , whereas the magnitude of the peak is reduced.