Understanding phonon polaritons and epsilon-near-zero modes in sapphire nanocones across the broad Reststrahlen band (385-1050 cm^-1).

ABSTRACT: Tailoring light-matter interactions is crucial for advancing nanophotonics. Surface phonon polaritons are promising candidates for enhanced light-matter interactions due to their efficient, low-loss light confinement. In this work, we experimentally investigate the Reststrahlen bands in sapphire across the infrared spectrum, spanning ω = 385-1050 cm^-1. We extended this investigation to nanocone-patterned sapphire resonators, with specific attention to its in-plane and out-of-plane permittivity components. Infrared spectroscopy and full-wave simulations revealed a range of optical excitations, including three surface phonon polaritons with quality factors as high as 40 ± 1, two hyperbolic volume phonon polaritons with quality factors as high as 83 ± 4, and one epsilon-near

SUBMITTER: Nourbakhsh M 

PROVIDER: S-EPMC12805809 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature