Light Funneling Profile During Enhanced Transmission Through a Subwavelength Metallic Slit

The funneling profile of enhanced light transmission through a subwavelength slit in a perfect electric conductor is studied with finite-difference time-domain simulation. From the wave-charge interaction dynamics, it is found that the EM wave energy is funneled while charges are accumulated at the edges of the slit. The Poynting vector indicates a boundary within which the wave energy flows toward the slit. Therefore, a funneling profile is defined by this boundary; as the slit width and thickness determine the transmitted energy density, the size of the funneling area is a relevant quantity of major concern.