双缝干涉 / Double-Slit Interference
条纹间距 Δx = —
可见亮纹: —
亮纹 Bright
暗纹 Dark
缝 S₁ S₂
λ 颜色
光源 / Light
双缝与屏 / Slits & Screen
演示要点 / Key points
⊕
波峰+波峰 → 亮纹
Crest + Crest = Constructive → Bright fringe.
⊖
波峰+波谷 → 暗纹
Crest + Trough = Destructive → Dark fringe.
Δ
Δx = λD/a，红光条纹更宽
Longer λ → wider fringe spacing.