Fano Resonances in Nanostructured Thin Films

Fano resonances are widespread in nature and technology. After their discovery almost 90 years ago [1] , Fano resonances found numerous applications in different fields. Especial growth of interest in Fano resonances in last years was boosted by emerging photonics and microphotonics technologies. The physics of Fano resonance can be explained by a coupled two-oscillator model: a driven oscillator with a broad resonance coupled to the second oscillator with a narrow resonance. When the frequency of the driving force is tuned around the resonance frequency of the second oscillator, a sharp variation is observed in the response of the first (driven) oscillator. The first oscillator, at a resonance with the second oscillator, shows zero response to the driving force – all the energy of the driving totally reflects. This can potentially introduce high frequency sensitivity in the system, thus the absorption and scattering can be efficiently engineered in a narrow frequency ranges.