Expanding Wavefront, Phase Oscillation, and Detector Fringes (Phase Addition)

Wavelength λ px Slit width a px Screen distance L px Sources across slit Animation speed x

Left: expanding wavefront from slit, hue = phase (k·r − ωt) Slit at x = 0, screen at x = L

The hue cycles with phase as the wave expands. This is a visualization aid, not literal color. The slit emits many Huygens sources across width a.

Right (left pane): detector screen brightness ∝ |Σ e^iθᵢ|² Right (right pane): intensity vs screen height Peaks = bright fringes, troughs = dark fringes

We compute complex phase addition of all slit sources for each detector position y: θᵢ = k·rᵢ − ωt, amplitude ∼ e^iθᵢ/rᵢ, then intensity(y) = |Σ_i e^iθᵢ/rᵢ|².