Presets
Mode
Live readout
What to try
Nanoparticle: sweep the wavelength and watch the near-field hot spots at the poles peak at resonance; raise the radius to see the red-shift; raise damping to flatten it. Metamaterial: pick a 60 nm cell, then slide the wavelength through the double-negative band and watch the refracted ray flip to the same side as the incident one.
Model checks
The science
A metal sphere much smaller than the wavelength is a quasi-static dipole with polarizability alpha = (eps - eps_m)/(eps + 2 eps_m) (times R³ and the field E0). The Drude permittivity is eps(E) = 1 - Ep² / (E² + i E gamma). The resonance is where Re(eps) = -2 eps_m (Fröhlich condition); damping gamma sets the width and the peak height. Outside the sphere the dipole field adds to the incident field, inside it is uniform 3 eps_m/(eps + 2 eps_m) E0.
A split-ring array is an LC resonator: mu_eff = 1 - F E² / (E² - E0² + i E Gamma), negative just above the ring resonance E0 (for E up to E0/sqrt(1-F)); the wire array gives eps_eff = 1 - Ep²/E². With both negative, n = -sqrt(eps mu) and Snell's law sin(theta1) = n sin(theta2) gives a refracted ray on the same side of the normal as the incident ray.
Honest simplifications: quasi-static dipole only (no retardation beyond the empirical plasma-energy shift used by the 3D lab), a single field amplitude scale factor 3.2 shared with the 3D page, loss-free slab geometry with no reflection coefficients, and a homogeneous-medium picture of the ring array.