Wave Optics

Each wavefront point emits secondary wavelets — envelope = new wavefront.

Fringe width β = λD/d. Live colored interference pattern on screen.

I = I₀(sin α/α)². First minimum at a sinθ = λ. Central max width 2λ/a.

Two synchronized sources — interference field with hyperbolic bright fringes.

I = I₀cos²θ. Two polarizers — angle determines transmitted intensity.

tan θ_B = n₂/n₁. Reflected ray fully polarized perpendicular to plane.

N slits — sharper, brighter principal maxima at d sinθ = mλ.

θ_min = 1.22 λ/D. Two Airy patterns transition resolved → unresolved.

2nt cosθ_t = mλ — soap film, oil slick, anti-reflection coatings.