Light at the end of a nanohole

Over the last few years the extraordinary transmission of EM waves through sub-wavelength apertures in an opaque sheet has been demonstrated experimentally and explained theoretically. To add another twist to the field, investigators are now marrying the unusual properties of negative-index materials with enhanced transmission through small apertures. In A. Alu et al. (2004) presented at the Monterey conference, it discussed how (at least theoretically) layers of metamaterials sandwiching a sheet with a small hole might also enhance transmission without any periodic structure, e.g., grooves, on the sheet.