Dual Evanescent Waves in a Single Resonance: Innovative Applications for Fano Resonance Biosensors

Surface plasmon resonance (SPR) sensors take advantages of label-free, real-time and surface-sensitive detection. The SPR technology is widely used for studying binding kinetics of various biomolecules. However, the typical SPR only has an evanescent depth. In this work, we discover a new phenomenon in aluminum capped nanoslit array which possesses two distant evanescent depths in a single Fano mode. This dual-mode in a single resonance property makes the Fano resonance useful for some innovative biosensing applications, such as self-referencing SPR sensors which applied in measuring the bio-reaction.