Engineering of high quality factor THz metasurfaces by femtosecond laser ablation

We report on the realization of high Q metasurfaces operating in the THz frequency range by femtosecond laser ablation applied to a nanometric metallic layer over a silicon substrate. Two different fabrication methods are used to develop periodic patterns whose basic elements are in form of an array of through-holes or metallic islands. The response of the resulting structures is characterized using a time-domain spectrometer in the frequency range 0.3-1.5 THz. The experimental findings are compared with the predictions of full wave electromagnetic simulations. The fairly good agreement between simulation predictions and experimental findings evidences that the proposed approach can offer a facile way to the elaboration of THz metasurfaces.