Single-Slit Diffraction — Fresnel vs Fraunhofer Regimes

Fraunhofer (far-field): I(θ) = I₀ sinc²(πa sinθ/λ). Fresnel (near-field): uses Cornu spiral / Fresnel integrals C(u), S(u). The Fresnel number F = a²/(λL) determines the regime: F≪1 → Fraunhofer, F≫1 → Fresnel.

Slit width a: 1.50 mm Distance L: 5.0 m λ: 532 nm

Fresnel number F = 0.00