Abstract: We present a both theoretical and experimental investigation into the effect of array periodicity on the filtering characteristics of metal/dielectric photonic crystals (MDPhCs) with hexagonal arrays of subwavelength holes in gold/silicon dioxide films, varying the array periodicity from 6 to 8 μ m every 1 μm while the ratio of hole radius to array periodicity is kept constant (1/4). The results indicate that the reflectance spectrum is highly dependent on the array periodicity. When the array periodicity increases, the reflectance spectrum exhibits a large redshift regularly. The finite difference time domain (FDTD) simulations agree well with the experimental results. By analyzing the relationship between the position of the reflectance minimum and the array periodicity, we find that the filtering characteristics of MDPhCs have an almost linear relationship with the array periodicity under the conditions of keeping the same ratio of hole radius to array periodicity (1/4). This finding provides an effective way to control the filtering characteristics of MDPhCs, which have potential applications in optical filters, plasmonic thermal emitters and so on.

Key words: optics at surfaces, surface plasmon polaritons, array periodicity, FDTD method, metal/dielectric photonic crystal, filtering characteristic