Nanoantenna as low-cost optical polarization sensor for remote sensing

Remote sensing for object identification depends on the intensity of infrared light, ranging from near-infrared ($0.8\mu \mathrm{m}$) to mid-wave infrared ($3\mu \mathrm{m}$), reflected or emitted by the object, providing information on one parameter. However, the surface orientation of any object has two degrees of freedom, which can be found by using polarized light. Hybrid sensors, consisting of external polarizers, have expensive manufacturing process. In this work, a bowtie nanoantenna with a gap size of 50nm, designed using an FDTD solver is illuminated with a light source of amplitude 1V/m and varying polarization to the nanoantenna axis. The electric field (EF) enhancement in the gap is 100 times larger in parallel polarization as compared to perpendicular polarization of incident light. The calculated absorption efficiency and polarization extinction ratio (PER) is found to be 80% and 21, respectively, in parallel polarization. This dependence paves the way for the application of nanoantenna as a polarization sensor. The array of the nanoantenna can be fabricated using low-cost printing techniques, thus providing inexpensive detection as compared to hybrid sensors.