物理与光电工程学院：《大学物理》课程PPT教学课件（讲稿，英文第三版）Chapter 30 The Wave Nature of Light, Interference

The Wave Nature of light: Interference Chapter 30 Chapter 30 The Wave Nature of light Interference 1 Huygens principle 2 Refraction 3 Youngs Double-slit Experiment--interference 4 Intensity in the Double-slit Interference Pattern 5 nterference in Thin Films 6 Michelson Interferometer

The Wave Nature of Light; Interference Chapter 30 Chapter 30 The Wave Nature of Light, Interference 1 Huygens’ principle 2 Refraction 3 Young’s Double-slit Experiment—interference 4 Intensity in the Double-slit Interference Pattern 5 Interference in Thin Films 6 Michelson Interferometer

The Wave Nature of light: Interference Chapter 30 Interference 干涉 Diffraction 衍射 Refraction 折射 Huygen's Principle惠更斯原理 index of refraction折射率 Double-slit 双缝 Bright fringe 明条纹 constructive interference干涉相长 Dark fringe 暗条纹 destructive interference干涉相消 Intensity 密度 Thin film 薄膜 Michelson interferometer麦克耳逊干涉仪

The Wave Nature of Light; Interference Chapter 30 Interference 干涉 Diffraction 衍射 Refraction 折射 Huygen’s Principle 惠更斯原理 index of refraction 折射率 Double-slit 双缝 Bright fringe 明条纹 constructive interference 干涉相长 Dark fringe 暗条纹 destructive interference 干涉相消 Intensity 密度 Thin film 薄膜 Michelson interferometer 麦克耳逊干涉仪

The Wave Nature of light: Interference Chapter 30 Rainbow: the incident wavelengths are bent through different angles as they pass through raindrops that produce the bow. (Geometrical optics However, soap bubbles(肥皂泡) and oil slicks (油膜) can also show striking colors, produced not by refraction but by constructive and destructive interference oflight. Light is wave, because interference(干涉)and diffraction(衍射) cannot be explained other than with waves

The Wave Nature of Light; Interference Chapter 30 Rainbow: the incident wavelengths are bent through different angles as they pass through raindrops that produce the bow. (Geometrical optics) However, soap bubbles（肥皂泡） and oil slicks （油膜） can also show striking colors, produced not by refraction but by constructive and destructive interference of light. Light is wave, because interference （干涉）and diffraction（衍射） cannot be explained other than with waves

The Wave Nature of light: Interference Chapter 30 30-1 Huygens Principle and Diffraction p680-681 1. Diffraction光的衍射现象(p681) If a wave encounters(遇到) a barrier(障碍物) that has an opening(fl) of dimensions similar to the wavelength, the part of the wave that passes through the opening will spread out (diffract) into the region beyond the barrier

The Wave Nature of Light; Interference Chapter 30 30-1 Huygens’ Principle and Diffraction p680-681 1.Diffraction 光的衍射现象 (p681) If a wave encounters（遇到） a barrier（障碍物） that has an opening（孔） of dimensions similar to the wavelength, the part of the wave that passes through the opening will spread out (diffract) into the region beyond the barrier

The Wave Nature of light: Interference Chapter 30 如果波长与障碍物相当,衍射现象最明显

The Wave Nature of Light; Interference Chapter 30 如果波长与障碍物相当，衍射现象最明显

The Wave Nature of light: Interference Chapter 30 圆孔衍射 Circular disk G 单缝衍射 Single slit

The Wave Nature of Light; Interference Chapter 30 圆孔衍射 Circular disk 单缝衍射 Single slit H P * S G * S

The Wave Nature of light: Interference Chapter 30 2. Huygens Principle惠更斯原理(p680-681) All points on a wavefront serve as point sources of spherical secondary wavelets(子波). After a time t, the new position of the wavefront will be that of a surface tangent to these secondary waⅴ lets 惠更斯原理一波在媒质中传播到的各点,都可看 成新的子波源。波振面上所有点都可视为发射子波的波 源,其后任一时刻,这些子波的包迹就是新的波振面 人人人 New wavefront

The Wave Nature of Light; Interference Chapter 30 2. Huygens’ Principle 惠更斯原理 (p680-681) 惠更斯原理----波在媒质中传播到的各点，都可看 成新的子波源。波振面上所有点都可视为发射子波的波 源，其后任一时刻，这些子波的包迹就是新的波振面. All points on a wavefront serve as point sources of spherical secondary wavelets（子波）. After a time t, the new position of the wavefront will be that of a surface tangent to these secondary wavelets. New wavefront

The Wave Nature of light: Interference Chapter 30 Planer wave Spherical wave 时刻的 t +△t 波阵面 时〈时刻的 刻 波阵面 的 波〈+2△ 阵区X时刻的 面〈波阵面 时刻的波阵面 +2△t 时刻的波阵面

The Wave Nature of Light; Interference Chapter 30 Spherical wave ut t +t 时刻的 波阵面 t 时 刻 的 波 阵 t + 2t 面 时刻的波阵面 Planer wave t 时 刻 的 波 阵 面 t +t 时刻的 波阵面 t + 2t 时刻的 波阵面 ut

The Wave Nature of light: Interference Chapter 30 30-2 Huygens Principle and the Law of refraction (p682) ○ The law of reflection: The angle of incidence(e,) The angle of reflection(01, 01 ○ The law of refraction sin e =12 SIn 2

The Wave Nature of Light; Interference Chapter 30 30-2 Huygens’ Principle and the Law of Refraction(p682) The law of refraction The law of reflection: The angle of incidence (1) = The angle of reflection (1 ’ ) 2 1 1 2 2 1 2 1 sin sin n n n v v = = =   1 1 ’ 2 n2 n1

The Wave Nature of Light: Interference Chapter 30 E B △太 △t

The Wave Nature of Light; Interference Chapter 30 r = ut r = ut 3 2 r = ut 3 A B 1 C D E F