Exceptional Points in Parity--Time-Symmetric Subwavelength Metamaterials

When sources of energy gain and loss are introduced to a wave scattering system, the underlying mathematical formulation will be non-Hermitian. This paves way for existence exceptional points, where eigenmodes linearly dependent. The primary goal this work is study points in high-contrast subwavelength metamaterials. We begin by studying parity--time-symmetric pair resonators prove that system supports asymptotic points. These at which eigenvalues eigenvectors coincide leading order parameter. then investigate exotic behavior metascreen composed repeating parity-time-symmetric pairs resonators. non-Hermitian nature structure means it exhibits unidirectional reflectionless transmission certain frequencies demonstrate extraordinary close these frequencies.