Optical planar chiral metamaterial designs for strong circular dichroism and polarization rotation

Planar chiral metamaterials comprising double-layer dielectric-metal-dielectric resonant structures in the shape of a gammadion are presented in the near-infrared regime. The unit cell of the doubly-periodic metamaterial design is optimized using the genetic algorithm for maximum circular dichroism and for maximum optical activity. A circular dichroism value in excess of 50% is predicted for the optimized design. Maximum polarization rotatory powers in terms of the minimum allowed transmittances are also obtained and presented. (c) 2008 Optical Society of America.