Electromagnetic modeling of multiwalled carbon nanotubes as nanorod electrodes for optimizing device geometry in a nanophotonic device

We present electric-field modeling of carbon nanotubes (CNTs) as nanorods to optimize electrode geometry in a light-modulating nanophotonic device based on CNTs and liquid crystals. The electric fields spawned by the nanotube electrodes are used to align the liquid crystal molecules to generate a gradient refractive-index profile. We considered an array of CNTs on a 2-D conducting substrate. Different geometries were realized by choosing one, two, three, and four CNTs at each point. The static electric fields produced by these different geometries were simulated. Our results show that the four nanotube groups generated a wide and symmetrical electric field as compared to other geometries. We have verified the simulation results by experimentally fabricating the nanophotonic device and found that the four nanotube groups formed a negative lens array in the liquid crystal cell with enhanced performance.