Fig. 2: Dispersion relation and nonlocal effect.
From: Two-plasmon spontaneous emission from a nonlocal epsilon-near-zero material
a The local permittivity of InSb εT with a carrier concentration Ne of 6 × 1018 cm-3. Here, ℏ is the reduced Planck constant, ωP is the plasma frequency, γ is the Drude damping rate. b–c Dispersion relations (b) and field confinement factor Lq/λq (c) of the the long-range surface plasmon polariton (LR-SPP) and the short-range surface plasmon polariton (SR-SPP) modes under the local-response assumption, respectively. Here, q is the in-plane momentum of the SPP. ℏωq is the modal energy, Lq is the modal length, and λq is the modal wavelength. The gray dashed line represents the epsilon-near-zero (ENZ) energy. d–e Dispersion relations (d) and field confinement factor (e) of the LR-SPP and SR-SPP modes under the nonlocal-response assumption, respectively.
