Matching Surface Plasmon Modes in Symmetry-Broken Structures for Nanohole-Based Color Filter

Metallic nanoholes have been highlighted by their possible use as plasmonic color filters (PCFs). However, previous results have demonstrated the functions of the PCFs as stand-alone components and have provided few explanations about the optimization of these structures. We provide a design method of the PCFs that offers unique analytic insights about extraordinary optical transmission (EOT) in a systematic manner. The dielectric environment in the cylindrical hole has an important role to match the surface plasmon (SP) modes in holes and subsequently to enhance the EOT. Efficient EOT was achieved with finite dimensions less than the penetration depth of the SPs. This letter will provide more realistic guidelines for designing nanohole-based applications.