Quasinormal Mode Theory of Chiral Power Flow from Linearly Polarized Dipole Emitters Coupled to Index-Modulated Microring Resonators Close to an Exceptional Point

• DOI: 10.1021/acsphotonics.1c01848
• Publication Date: 2022-03-09T23:12:19Z
• Authors: Juanjuan Ren; Sebastian Franke; Stephen Hughes
• Keywords: 0103 physical sciences; FOS: Physical sciences; 01 natural sciences; Physics - Optics; Optics (physics.optics)

Chiral emission can be achieved from a circularly polarized dipole emitter in nanophotonic structure that possesses special polarization properties such as singularity, namely, with right or left (C-points). Recently, Chen et al. [Nature Physics 2020, 16, 571] demonstrated the surprising result of chiral radiation linearly (LP) and argued this effect is caused by decoupling underlying eigenmodes non-Hermitian system, working at an exceptional point (EP) region. Here we present quasinormal mode (QNM) approach to model index-modulated ring resonator near EP show similar unusual power flow LP emitters, direct agreement experimental results. We explain these results quantitatively correct eigenmodes, which are QNMs supported resonator. By coupling two dominant resonator, how depends on position orientation emitter, also verified excellent respect between QNM theory full numerical solutions. normal solution fails capture chirality since it does not take into account essential phase. Moreover, demonstrate one achieve frequency-dependent replace lossy materials gain index modulation reverse chirality.