Waveguide-Plasmon Polariton Quasiparticles with Exceptional Point Characteristics

The growing complexity of integrated photonics necessitates compact, low-power devices that transcend traditional, material-centric design approaches. In this study, we harness non-Hermitian physics to uncover novel properties of coupled plasmonic waveguide modes exhibiting exceptional point (EP) degeneracy. Our hybrid plasmonic waveguide architecture, capable of supporting both strong and weak coupling regimes between plasmonic and dielectric waveguide modes, is precisely engineered to reach an EP where eigenmodes coalesce. This strategic tuning not only enhances the modal contrast between minimized-loss and highly dissipative states but also enables unprecedented control over device characteristics. Our findings introduce a new paradigm in integrated photonics, paving the way for ultracompact modulators and highly tunable on-chip communication systems with reduced power consumption.