Chiral Metamaterials with P T Symmetry and Beyond

Optical systems with gain and loss that respect parity-time (P T ) symmetry can have real eigenvalues despite their non-Hermitian character. Chiral systems impose circularly polarized waves which do not preserve their handedness under the combined space- and time-reversal operations and, as a result, seem to be incompatible with systems possessing P T symmetry. Nevertheless, in this work we show that in certain configurations, P T symmetric permittivity, permeability, and chirality is possible; in addition, real eigenvalues are maintained even if the chirality goes well beyond P T symmetry. By obtaining all three constitutive parameters in realistic chiral metamaterials through simulations and retrieval, we show that the chirality can be tailored independently of permittivity and permeability; thus, in such systems, a wide control of new optical properties including advanced polarization control is achieved.