Extraordinary infrared transmission of a stack of two metal micromeshes

Two Ni microarrays, stacked in registry with zero open area through the assembly and a subwavelength spacing between the mesh, exhibit transmission resonances through the mid-infrared region that are similar to those of a single mesh. Propagating surface plasmons are coupled between the meshes with this arrangement producing narrower resonances that are isolated from direct transmission. The dispersion behavior of the transmission resonances is well-modeled by propagating surface plasmons if allowances are made for a splitting of the surface plasmon dispersion curve in momentum space because of the coupling of the front and back surfaces of each mesh and perhaps between the meshes. These techniques will be useful for passing infrared radiation through nanospaces enclosed within the mesh stack.