We theoretically investigate the optical properties of parity-time (PT)-symmetric three dimensional metamaterials composed of strongly-coupled planar plasmonic waveguides. By tuning the loss-gain balance, we show how the initially isotropic material becomes both asymmetric and unidirectional. The highly tunable optical dispersion of PT -symmetric metamaterials provides a foundation for designing an entirely new class of three-dimensional bulk synthetic media, with applications ranging from sub-diffraction-limited optical lenses to non-reciprocal nanophotonic devices.

http://arxiv.org/abs/1306.0059
Optics (physics.optics)