Highly Q-factor optical metasurface based on DNA nanorods with Fano response for on-chip optical sensing

In this paper, a MIM metasurface is suggested for optical sensing based on nanorods of DNA which are placed over the metal layer. The nanorods can increase the absorption of the energy and thus the reflection value reduces extremely in comparison to the uncoated surface. Here, the nanorods of DNA are used to amend the reflection from -23 to -37 dB and so the Q-factor is increased from 90 to 784 at 330 THz. The parametric studies are investigated to realize the effect of the height and radius of nanorods on the reflection of the proposed metasurface. Finally, this metasurface is utilized as a refractive index sensor at the optical spectrum and the figure of merit and the sensitivity are obtained 90 nm/RIU and 1378 RIU-1 respectively which is acceptable in comparison to previous researches. At last, the effect of conductivity of the DNA composite on the reflection for high and low conductivity is compared for the proposed metasurface whereas the permittivity of the DNA is supposed a constant value.