Enhanced fano resonance in asymmetric nano dimer for sensing applications

Fano resonance (FR) owns a sharp asymmetric line shape, low radiation loss and huge modification ability so that enhancing Fano resonance in asymmetric dimers is a topic of interest in nanophotonics and plasmonics, which has potentials in sensing applications. Here, we theoretically investigated the enhancement and tunability of Fano resonance in shape-asymmetric gold nanoring-nanodisk dimer through varying the size of nanodisk (ND) and polarization angle (θ). The intensity of this mode was significantly enhanced by changing the aforementioned parameters. Furthermore, we studied the performance of FR in terms of the quality factor (QF) and figure of merit (FoM). It is found that the QF (FoM) of this mode decreases (increases) exponentially (linearly) with increasing ND and θ. We explored the sensitivities of FR with maximum FoM to assess the capability of this mode in the detection of refractive index. Moreover, our design displays enhanced performance by increasing the size of ND and the polarization angle of the incident light offering another degree of freedom for exploring and modulating asymmetric dimers. This approach provides insights into the enhanced and tunable FR with remarkable potential in sensing and switching applications.