Spoof-surface-plasmon assisted light beaming in mid-infrared

摘要

We have investigated light beaming through a single slit in a silver thin film with periodic gratings on the output side in the mid-infrared wavelength range. We show that light beaming in mid-infrared is mainly controlled by spoof surface plasmons. We take account of both the dispersion relation and the phase-matching condition of spoof surface plasmons to obtain good beaming efficiency. Through engineering the geometrical parameters of the grating structures, we can achieve the desired near-field and far-field distribution in mid-infrared.