Observation of the influence of the gain on parity-time-symmetric properties of photonic molecules with coupled whispering gallery modes

Abstract

Parity-time (PT) symmetry breaking in coupled whispering gallery mode type resonators is studied by finite-difference time-domain modeling. Normal mode splitting is studied as a function of the coupling strength. It is demonstrated that in bi-atomic molecules with distributed gain and loss, reduction of the coupling beyond a certain value leads to PT symmetry breaking.