Fabrication of frequency-selective surface structures by femtosecond laser ablation of gold films

Simple frequency-selective surface (FSS) structures consisting of two-dimensional (2D) triangular lattices of circular apertures with an aperture diameter of about 0.6-0.8 μm and a lattice period of 1.0 and 2.0 μm were fabricated by femtosecond laser ablation of thin gold films deposited on glass substrates. The fabricated samples were found to exhibit spectral transmission bands at infrared wavelengths, and significant surface plasmonic (SP) local enhancement of the near-field near the metal's surface according to experimental transmission measurements and theoretical simulation by Finite-Difference Time-Domain (FDTD) technique. These results indicate versatility of femtosecond laser ablation technique for rapid prototyping of metallic FSS and plasmonic structures.