Fishnet Metamaterial 2D: Negative-Index Ray Diagram & Dispersion

A fishnet metamaterial stacks two perforated metal sheets around a thin dielectric spacer so that an incident magnetic field drives antiparallel currents through the holes, forming a resonant current loop with a genuine magnetic response — something no natural material offers at optical frequencies. This 2D companion to the 3D fishnet simulator keeps the same Drude-electric-plus-Lorentzian-magnetic effective-medium model and computes the identical complex index n(ω) = √(ε(ω)·μ(ω)), but renders it as a flat, pannable/zoomable ray diagram instead of a 3D stack, and adds a live power-reflectance readout and a full dispersion strip sweeping Re(n) and Im(n) across the whole frequency band at the current geometry — a genuinely 2D-native diagnostic with no 3D equivalent. Sweep the incident frequency, the hole-size resonance, the inter-layer coupling and the metal damping to watch the transmitted ray flip to the same side of the normal as the incident ray whenever Re(n) drops below zero.