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Spatial Dispersion and Effective Constitutive Parameters of Electromagnetic Metamaterials
Ist Teil von
Tutorials in Metamaterials, 2012, p.271-306
Ort / Verlag
United Kingdom: CRC Press
Erscheinungsjahr
2012
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
Optical properties of metamaterials are conceptually dierent from those of the natural
materials. Most of these dierences can be traced back to the fact that the unit cell of
a natural material is extremely small whereas that of most metamaterials is, generally,
not. e relevant spatial scale to compare the unit cell’s size a of either natural material
or metamaterial is the wavelength of light λ. e unit cell’s size of a natural material is
only on the order of the Bohr’s radius aB ≈ 0.5 = 5 × 10-9 cm. erefore, it is four orders
of magnitude smaller that the wavelength λ = 500 nm of the visible light in vacuum.
One implication of that is the negligible phase shi¹ of a propagating electromagnetic
(or optical) wave across the unit cell. Specically, this phase shi¹ φ pi λ= 2 1na/ unless
the refractive index of the material n > 103. Such a refractive index would correspond to
the dielectric permittivity e = n2 > 106. No such materials exist in nature.