华中科技大学 工程光学第五章 光的偏振和晶体光学基础.pptVIP

光是电磁振荡的一种传播。其中电场和磁场的振动方向垂直，为方便计，以下只考虑电振动。 Brewster David Brewster (1781-1868), Scottish physicist, professor of physics at St. Amdrews College. Initially a minister in the Church of Scotland, Brewster became interested in optics, found the angle named after him, contributed also the dichroism, absorption spectra, and stereo-photography, invented the kaleidoscope, and wrote a book about it. Brewster’s Law Brewster’ law, in his own words, states that “when a ray of light is polarized by reflection, the reflected ray forms a right angle with the refracted ray. On the laws which regulate the polarization of light by reflection from transparent bodies.” Malus Etienne Louis Malus (1775-1812), French army officer and engineer. One evening in 1808 while standing near a window in his home in Paris, Malus was looking through a crystal of Iceland spar at he setting sun reflected in the windows across the street. As he turned the crystal about the line of sight, the two image of the sun seen through the crystal became alternately darker and brighter, changing every 90o of rotation. After this accidental observation Malus followed it up quickly by more solid experimental work and concluded that the light by reflection on the glass, became polarized. 晶体的主折射率，正晶体、负晶体 各电磁矢量的相互关系 单轴晶体中光的传播 单轴晶体中o、e光的分离角 §5－5 晶体偏振器件 偏振棱镜 格兰-汤姆逊 偏振棱镜 Comments Nicol prism is a good polarizer, but it is expensive and has a limited field of view (28o). The Glan-Thompson prism has a wider angular aperture (40o), but is wasteful of calcite and hence even more expensive. The Glan-Foucault prism has no cement (but a narrow field) and thus is less likely to be damaged at high power densities. 沃拉斯顿 偏光分束棱镜 椭圆偏振光与圆偏振光的检偏 Homework(5-5) 1. Two Nicol prisms are set for maximum transmission. If one prism is rotated through 60o 1) What percentage of the amplitude is still going through? 2) What percentage of the amplitude is still going through? 2. Ice is a positive uniaxial crystal with indices of