Get started
Work

Dual-dielectric-tunable surface phonon polaritons in quasi-one-dimensional MgO nanotubes

Year: 2026
Type: article
Abstract: Conventional quasi-one-dimensional (Q1D) polar nanowires support surface phonon polaritons (SPhP) only within the lower portion of the Reststrahlen band, leaving an unnegotiable upper forbidden gap that wastes mid-infrared spectral resources and limits device versatility. Existing dielectric tuning schemes rely on a single surrounding medium, lacking independent control over multiple polariton branches and restricting further progress in polariton engineering. Here, SPhPs in Q1D cubic MgO nanotubes are systematically explored via the dielectric continuum model with an inner-outer dual-dielectric configuration. Two SPhP branches emerge and can fully occupy the entire MgO Reststrahlen band when the inner dielectric permittivity is greater than or equal to the outer dielectric permittivity, where the low-frequency branch corresponds to in-phase bonding-state surface coupling and the high-frequency branch originates from out-of-phase antibonding-state coupling, eliminating the intrinsic forbidden band of nanowires. The outer dielectric selectively modulates the dispersion, wavelength compression, and group velocity of the low-frequency branch, while the inner dielectric tunes both branches and enables group-velocity sign reversal. Synchronous dielectric adjustment delivers much stronger modulation than single-medium tuning. Electric field distributions reveal distinct surface localization for the two modes, underpinning their independent dielectric tunability. This work establishes a dual-dielectric modulation paradigm for tubular polar nanostructures and provides design guidelines for broadband mid-infrared polaritonic devices.
DOI: 10.1364/oe.612129
Language: English
Open Access status: gold
Estimated APC paid: $2,270
OpenAlex ID: W7223410156
FWCI:
Cites: 64
Cited by:
Related to: 10