PT-axisymmetry for extraordinary field confinement

Abstract

Optical Parity-Time (PT-) symmetric systems support unusual properties when the symmetric coupling between internal modes is broken. We propose a new class of quasiperiodic PT-axisymmetric systems which lead to a simultaneous extraordinary field enhancement and localization at the symmetry center. The effect is based on the asymmetric radial coupling of outward to inward propagating waves of the complex structure. We explore such optical potentials in 1D and 2D combining gain/loss and index modulations, which could have actual realizations in nanophotonic structures. As a direct application, we show how to render a broad aperture vertical-cavity surface-emitting lasers (VCSEL) into a bright and narrow beam source.