Plasmonic Sensing and Modulation Based on Fano Resonances

The rapid developments in nanotechnology and plasmonics allow the manipulation of light at nanometer scales, such as light propagation and resonances. Differing from the symmetric Lorentzian‐like profiles in the conventional resonances, Fano resonances, which originate from the interference of different resonant modes, exhibit obviously asymmetric spectral profiles. Based on lineshape engineering, the Fano resonances with sharp asymmetric profiles exhibit a small linewidth and a high spectral contrast by exploiting different mechanisms and designing various metallic nanostructures. Both of the above properties in the sharp Fano resonances have significant applications in nanoscale plasmonic sensors and modulators. This review summarizes the underlying mechanism of the Fano resonances in various metallic nanostructures. Then, practical applications of the Fano resonances in nanoscale plasmonic sensing and modulation are reviewed. At last, the development and challenges of plasmonic sensing and modulation based on Fano resonances are discussed. Fano resonances, which originate from the interference of different resonant modes in metallic nanostructures, show obviously asymmetric spectral profiles. Based on lineshape engineering, the Fano resonances exhibit small linewidths and high spectral contrasts, which are significant for the application in nanoscale plasmonic sensors and modulators. The mechanisms of the Fano resonances and their applications in plasmonic sensing and modulation are reviewed.