[17p-Z31-1~15] 3.11 Photonic structures and phenomena

[17p-Z31-5] Non-Hermitian coupled mode theory for cavity arrays with gain and loss

〇Kenta Takata^1,2, Nathan Roberts^2,3, Akihiko Shinya^1,2, Masaya Notomi^1,2,4 (1.NTT Nanophotonics Center, 2.NTT Basic Research Labs., 3.Univ. Bath, 4.Tokyo Inst. Tech.)

Keywords:coupled cavities, exceptional point, photonic crystal

We report a non-Hermitian coupled-mode theory for cavities with gain and loss. We show that contrast of the effective imaginary potential induces imaginary parts of cavity couplings as second-order terms. The exceptional point (EP) degeneracy is generally lifted and the band singularity is hence blurred by the existence of this imaginary coupling. However, we clarify that this effect is cancelled and thus the EP is restored in the system with balanced gain and loss. We demonstrate the validity of our model with a simulation of an array of buried heterostructure nanocavities.