(光的干涉).pptVIP

* the Doppler effect the nature of light, wave-particle duality Light as electromagnetic waves Coherent light, Interferences of light Optics Geometric Optics ray model, path reversible Wave Optics: Wave model electromagnetic waves, Huygens’ principle Quantum Theory: particle-wave duality, etc reflection refraction imaging prism interference diffraction polarization Photoelectric effect Compton effect Blackbody radiation Interference of Light （光的干涉） Conditions for Interference （干涉条件） identical wavelengths constant phase difference vibrating in parallel direction Conditions for interference fulfilled? coherent incoherent Yes No Again, to observe obvious interference effects, the intensity difference between the individual waves can’t be too large . Optical Path Length （光程） Path length: f light Young’s Double-Slit Experiment （杨氏双缝试验） Optical Path Difference in Double-Slit Experiment Case 1: interfere constructively bright fringes （亮纹） Case 2: interfere destructively dark fringes （暗纹） Order Number of Bright Fringes （亮纹的级数） y = 0, central bright fringe （中央亮纹） m = 0: zeroth-order maximum （零级极大） m is called order number. y = λL/d, first-order maximum （ m 称为级数） (一级极大) Spatial Distribution of the Fringes Bright Fringes Dark Fringes angular positions （干涉条纹的空间分布） Intensity Distribution of the Double-Slit Interference Pattern （双缝干涉图样的强度分布） Monochromatic light（单色光） As discussed above. White light（白光） All bright fringes except the central one are chromatic. About the Light Source The position of the bright fringes: （除了中央亮纹，其他亮纹都是彩色的） Question If there exists medium in space, the refraction index of which is n, what are the positions of the bright and dark fringes? Lloyd’s Mirror （劳埃德镜） Dark fringe is found at p’ due toπ-phase shift. Fresnel’s Double-Mirror （菲涅尔双镜） Interference pattern can only be observed in dark zone. （只有阴影区域可以观察到干涉图样） Interference in Thin Films （薄膜干涉） film air Lenses do not influence the optical path difference （透镜不引起附加的光程差） interfere c