工程光学英语补充内容和习题.ppt

1、1,English Summary,1. The electromagnetic spectrum,long,short,Wave length,380nmviolet-blue 780nmdeep-red,2,2. Law of Rectilinear propagation,Light as it advances through free space or through homogeneous, isotropic matter follows a beeline. (a direct straight course). Example: Shadows,3,3. The Law of

2、 Reflection,A light ray striking a reflecting surface and reflected from it makes equal angles with the normal to the surface at the point of incidence, I=-I and the incoming ray, the outgoing ray, and the normal to the surface at the point of intersection all lie in the same plane.,4,4. The Law of

3、Refraction,The angle made by the incident ray, that made by the refracted ray, and the surface normal at the point of incidence in a refractive process obey the expression nsinI=nsinI The incident ray, the refracted ray, and the surface normal are all coplanar.,5,5. Total Internal Reflection,6. Ferm

4、at principle,Light takes the path that requires the least time.,6,7. Key words and concept,Image space extends from infinity on one side to infinity on the other. The same holds for the object space; both completely overlap. Whether a given point is in the object space or the image space depends on

5、whether it is part of a ray before or after refraction. If a given point is in the object space, it is a point object, otherwise it is a point image.,7,Homework,1. In ancient times the rectilinear propagation of light was used to measure the height of objects by comparing the length of their shadows

6、 with the length of the shadow of an object of known length. A staff 2m long when held erect casts a shadow 3.4 m long, while a buildings shadow is 170 m long. How tall is the building? 2. Light from a water medium with n=1.33 is incident upon a water-glass interface at an angle of 45o . The glass i

7、ndex is 1.50. What angle does the light make with the normal in the glass? P12 4 2) the microscope is used for visual observation. P140-3&6,56,Supplementary materials,1. Digital camera,工作原理 颜色的形成 分色棱镜 覆盖 转轮 指标 像素数 颜色深度,57,Supplementary materials,BAYER编码,三色编码,58,Homework,Classification of camera lens

8、es: 1)Tessar camera lens (most widely used) 2) Telephoto lens 3) Wide-angle lens, fisheye lens ,sky lens 4) A zoom lens P140-5&7,59,Brief history of laser,The word LASER is an acronym for light amplification by stimulated emission of radiation. In 1916, Einstein predicted that the existence of equil

9、ibrium between matter and electromagnetic radiation required that besides emission and absorption there must be a third process, now called stimulated emission.,60,This prediction attracted little attention until 1954, when Townes and coworkers developed a microwave amplifier (Maser) . In 1958, Scha

10、wlow and Townes showed that the maser principle could be extended into the visible region. In 1960, Maiman built the first laser using ruby as the active medium.,Brief history of laser,61,Compared to radiation from other sources, laser radiation stands out in several ways. It has a particular beam s

11、hape and divergence. It is highly coherent, both spatially and temporally. It is eminently suited to produce interference.,Special characteristic,62,Often it is polarized as soon as it leaves the laser cavity. It can be generated in the form of very short pulses, at high powers and because of its hi

12、gh spatial coherence, at very high power densities.,Special characteristic,63,Keywords and concept,1. OTF (Optical Transfer Function) It is the ratio of the Fourier transform of the light distribution in the image to the Fourier transform of the light distribution in the object. It is used to descri

13、be the degradation of an image of different space frequencies. OTF=MTFei,64,2. MTF (Modulation Transfer Function) It is the ratio of the modulation in the image to modulation in the object. It varies as a function of spatial frequency. A perfect lens should have a modulation transfer factor of a uni

14、ty at all frequencies. In fact, MTF is close to unity at low space frequencies, and declines at higher frequencies.,Keywords and concept,65,3. PTF (Phase Transfer Function) It varies as a function of spatial frequency. A perfect lens should have a phase transfer factor of 0 at all frequencies. In fact, PTF is close to 0 at low space frequencies, and increases at higher frequencies.,Keywords and concept,66,4. Spatial f