Applications of asymmetric 2D and 3D gold Fano resonators and optical realization approach

Split ring resonator based metamaterials have shown numerous applications in biomolecular sensing, protein detection, and extraordinary transmission. This article presents FDTD simulation studies for different applications of asymmetric 2D and 3D gold resonators towards highly sensitive, and polarization as well as incident angle independent refractive index sensing with high figure of merit (FOM) and circular dichroism, respectively. Graphene layer coating over these 2D sensors are observed to enhance the sensitivity through coupling of electromagnetic waves to plasmonic excitation. Among all the resonators arranged in a square lattice, triple C-shape asymmetric Fano resonator presents an enhanced sensitivity of 606 nm/RIU and quadruple C-shape resonator present a high FOM of 16.5 with polarization and incident angle independency. A hexagonally packed asymmetric dual C-shape resonator presents multiple magnetic resonant modes with a maximum FOM of 27 and sensitivity of 981 nm/RIU within 1200-1400 nm wavelength range. The sensitivity of the designed Fano resonators in the NIR wavelength matches with the vibrational modes of proteins and, hence, can be applicable in bimolecular sensing. A computational simulated intensity profile based on multibeam interference is presented to propose a cost-effective realization for various multidimensional symmetric and asymmetric structures. The realization possibility of an asymmetric rectangular spiral PhC arranged in a hexagonal lattice is demonstrated for the first time through this technique using 3D printing.