💡 1D Photonic Crystal — Bragg Mirror Spectrum (2D)

This 2D companion runs the exact same physics as the 3D original — the transfer-matrix method for a 1D dielectric stack — through a plain canvas view built for reading the numbers rather than orbiting a scene: a side panel exposes the period count, both refractive indices, the design wavelength and fill ratio, a stack diagram shows the actual built layer sequence with its real physical thicknesses, and a colour-coded transmission spectrum plots T(λ) from 300–1200 nm with the photonic bandgap shaded and the probe wavelength marked, so the effect of every control on the gap's centre, width and depth is visible at a glance instead of inferred from a rotating 3D stack.