Controlling Strong Electromagnetic Fields at a Sub-Wavelength Scale

Abstract

We investigate the optical response of two sub-wavelength grooves on a metallic screen, separated by a sub-wavelength distance. We show that the Fabry-Perot-like mode, already observed in one-dimensional periodic gratings and known for a single slit, splits into two resonances in our system : a symmetrical mode with a small Q-factor, and an antisymmetric one which leads to a much stronger light enhancement. This behavior results from the near-field coupling of the grooves. Moreover, the use of a second incident wave allows to control the localization of the photons in the groove of our choice, depending on the phase difference between the two incident waves. The system exactly acts as a sub-wavelength optical switch operated from far-field.

5 pages, 4 figures, submitted to PRL

Cited by in corpus (4)

• Bandwidth control of forbidden transmission gaps in compound structures with subwavelength slits
• Mode-balancing far field control of light localization in nanoantennas
• Light enhancement on thin and ultra-thin high-index dielectric slabs with rectangular nano-pits
• Origin of the Norton-type wave scattered by a sub-wavelength metallic slit