Reconfigurable parity-time symmetry transition in phase change metamaterials

Although the conceptually remarkable, experimental illustration of parity-time (PT) symmetric quantum systems stays unexplored, their photonics analogues are explored by taking advantage of the similarity between the Helmholtz and Schrödinger equations. However, the static nature of the constitutive parameters of photonics structure inherently limits an achievement of dynamic PT-symmetry transition. We propose mid-infrared metamaterials (MMs) consisting of two orthogonally orientated metallic meta-atoms with one resonator integrated by a chalcogenide glass, GeTe. The PT-symmetry breaking can be actively transited to PT-symmetry by varying the structural state of GeTe between amorphous and crystalline while fixing the MM geometry. An electric-thermal model is constructed to illustrate that reversible switching between PT-symmetry and PT-symmetry breaking can be obtained in ∼270 ns. Our theoretical work lays the basis for designing high-speed reconfigurable PT-symmetry photonics systems that provide a promising approach for dynamically engineering non-Hermitian quantum symmetry.