All-Dielectric Nanohole Array for High-Resolution Imaging and Enhanced Sensitivity

Subwavelength periodic structures have been intensively investigated for sensing applications due to the exquisit photon control they offer [1]. In particular, plasmonic nanoapertures, or "nanohole arrays" have been widely studied due to their high sensitivity to refractive index changes, e.g. allowing the detection of human proteins down to 10 pg/mL [2]. However, the optical transmission through a plasmonic nanohole array is limited by metal losses, resulting in a typical extinction ratio (ER) <; 0.1, together with low Q-factors that make further improvements difficult.