Broken-diabolo nanoantenna for co-enhancing and -confining optical electric and magnetic field

In this letter, we introduce a broken-diabolo nanoantenna aimed at generating electric and magnetic hot spots in the near-infrared range, thus enhancing and confining the electric and magnetic optical field simultaneously. This nanoantenna different from the well-known diabolo nanoantenna and bowtie nanoantenna in that it can accumulate a large charge density at the upper air gap and a high optical current density within the lower central junction, leading to a large electric and magnetic field enhancement near the center of the nanoantenna at the same time. Numerical simulation results on this broken-diabolo nanoantenna show that a 5-fold enhancement of electric field (compare to the electric field enhancement of a diabolo nanoantenna) is achieved at a wavelength of 2353 nm, confined to a 40-by-40 nm region near the center of the nanoantenna.