光电信息科学与工程专业英语教程（第2版）全套完整教学课件.pptx

第一章Ray Optics光电仪器类专业教材光电信息科学与工程专业英语教程(第2版)ch01Ray Optics.pptxch02Wave Optics.pptxch03Holography and Fourier Optics.pptxch04Lasers.pptxch05Optical Fiber Communication.pptxch06Optical Components.pptxch07Applied Techniques.pptxch08How to Write Scientific Papers.pptx全套可编辑PPT课件 01Refraction and ReflectionPART ONE 1.RefractionWhen a light ray strikes a smooth interface between twotransparent media at an angle it is refracted. Fach medium maybe characterized by an index of refraction n, which is a usefulparameter for describing the shatpness of the refraction at theinterface. The index of refraction of air (more precisely, of freespace) is arbitrarily taken to be one, n is most convenientlyregarded as a parameter whose valuc is determined byexperiment We know now that the physical significance of n isthat the ratio of the velocity of light in vacuo to that in the medium 1.RefractionSuppose that the ray is incident on the interface, as shown in Fig.1.1, It is refracted in such away thatnsini=nsin ino matter what the inclination of the incident ray to the surface, n is the index of refraction of thefirst medium, n that of the second. The angle of incidence i is the angle between the incident rayand the normal to the surface; the angle of refraction f’ is the angle between the refracted ray andthe normal. 2.Index of RefractionMost common optical materials are transparent in the visible region of the spectrum,whosewavelength ranges from 400 to 700nm. They exhibit strong absorption at shorter wavelengthsusually 200nm and below.The refractive index of a given material is not independent of wavelength, but generallyincreases slightly with decreasing wavelength (Near the absorption edge at 200 nm, the index ofglass increases sharply). This phenomenon is known as dispersion. Dispersion can be used todisplay a spectrum with a prism; it also gives rise to unwanted variations of lens properties withwavelength. Table 1.1 gives typical index of refraction of several materials. 2.Index o