Phonons and excitons for omnipolarization surface waves

Tailoring near-field optical phenomena often requires excitation of surface plasmon or surface phonon polaritons, surface waves occurring at the interface between media with opposite dielectric permittivities. Despite the unprecedented mode confinement of these waves, they are limited by polarization; only transverse magnetic (TM) fields enable their excitation. We demonstrate that high-permittivity materials can support transverse electric (TE) surface-confined propagation, for which we investigate polar dielectrics near their phononic resonances (Reststrahlen bands) and semiconductors near their excitonic resonances that lie at infrared and visible frequencies, respectively. By combining those with plasmonic materials in subwavelength bilayers, we identify regimes where simultaneously TE and TM phase-matched surface waves occur, with figures of merit and confinement factors comparable to plasmons. We introduce a general approach for surface waves computations, applicable to any finite or infinite layered system, with arbitrary individual layer thicknesses, and arbitrary (periodic or aperiodic) sequence of layers, by combining the reflection pole method with parameter-retrieval approaches, traditionally employed for determination of metamaterials’ effective parameters.