Metamaterials
Artificially engineered composite structures designed with subwavelength resonant features that display electromagnetic properties not found in natural materials.
Governing formula
n_refractive = - √(ε_r μ_r) (Negative Refractive Index)
SI unit
Dimensionless Index n < 0
In depth
By structuring micro-resonators (like split-ring resonators) smaller than light wavelengths, metamaterials achieve simultaneous negative permittivity ε < 0 and negative permeability μ < 0, yielding negative refraction and super-resolution imaging.
Examples in the real world
Electromagnetic cloaking devices bending microwaves smoothly around objects, and flat super-lenses surpassing diffraction limits.