Chapter1BasicPrinciplesofGeometricalOptics.ppt

1、Applied Optics （English）,JIHONG ZHENG 2015-10-08,Outline,1）know each other；2）brief introduction of this course；3）course requirements；4）how to teache？ how to learn this course？5）what will you know after you learn this course? what should we do?6) some useful information,Dr. JIHONG ZHENGContact inform

2、ation: 55271586, address: Optical Engineering Research Institute Building No.418,1 Introduction of instructor:,Requirements:1 Join the class on time2 Use your brain 3 English teaching class4 take part in the discussion5 normal performance lab (30%-40%) + final exam (60%-70%),2 Course requirements:,3

3、 Teaching content：, Theoretical partChapter 1 basic principle of Geometrical optics ( beam, wavefronts, reflection law, refraction law etc)Chapter 2 Symmetrical system made from spherical surfaces ( optical system, ideal system etc )(*)Chapter 3 Mirror and PrismChapter 4 Stops of optical system (*),

4、Chapter 5 Aberration of Optical system Chapter 6 practical optical system ( eyes, microscope, telecscope) Second Part : Experiments: (6 Experiments) Third part:Software(Zemax, if the time is available),3 Teaching content：,4 Reference books：,Applied Optics（2nd edition）（李林主编 北京理工大学出版社）工程光学（科学出版社，李湘宁主编

5、）,What is Light ?,1. Electromagnetic (EM) wave -In the wave view,2. A ray or beam -In the geometric optics view,3. A stream of photons - In the quantum view,Wavelength: Velocity: c,Frequency: ,The period: T,Spectrum, = 1/T, = c,Interference,Chapter 1 Basic Principles of Geometrical Optics,Waves and

6、RaysBasic Laws of Geometrical OptocsRefractive Index and Speed of LightReversibility of Ray Paths and Total Internal ReflectionVector Form of Basic LawsClassification of Optical Systems and Concept of ImagingIdeal Images and Ideal Optical Systems,下一页,结束放映,1.1Waves and Rays（光谱分布）,Electromagnetic wave

7、s with wavelengths between 400nm and 760nm are called the visible light.,Ultraviolet: 190400nmViolet: 400 - 420 nm Indigo: 420 - 440 nm Blue: 440 - 490 nm Green: 490 - 570 nm Yellow: 570 - 585 nm Orange: 585 - 620 nm Red: 620 - 780 nm,（可见光波谱图）,Speed of light（光速）,The speed of light in a vacuum is def

8、ined to be exactly 299,792,458 m/s (approximately 186,282 miles per second). The fixed value of the speed of light in SI units results from the fact that the metre is now defined in terms of the speed of light. All forms of electromagnetic radiation move at exactly this same speed in vacuum.Differen

9、t physicists have attempted to measure the speed of light throughout history. Galileo attempted to measure the speed of light in the seventeenth century.,Wave nature of light,where v is the velocity of the wave in the medium. In free space, v = c = 3 x108m/s,Example: If is 0.85 m (free space), find

10、the frequency.,Example: If f = 1 THz, find the wavelength in free space.,Light is presented as geometrical lines. A geometrical line is called a ray.A ray is a normal to wavefronts, whereas a wavefront is a surface perpendicular to all the rays.,wavefronts of a point source,Wavefront (波前),球面波前,非球面波前

11、,平面波前,1.2 Basic Laws of Geometrical Optics (1) straight line,(1)Rays propagate along straight lines in a homogeneous and transparent medium（光的直线传播）,影子的形成,小孔成像,(2)Light independent propagation law（光的独立传播）When two or more lights met in the space, the propagation of the light will not be affected by ot

12、her light.,projector,1.2 Basic Laws of Geometrical Optics (2) independent beams,(3)the law of reflection and the law of refraction at the interface of two homogeneous media（反射和折射定律）,1.2 Basic Laws of Geometrical Optics (3) reflection and refraction law,Reflection（反射）,Refraction（折射）,When a beam of li

13、ght crosses the boundary between a vacuum and another medium, or between two different media, the wavelength of the light changes, but the frequency remains constant. If the beam of light is not orthogonal (or rather normal) to the boundary, the change in wavelength results in a change in the direct

14、ion of the beam. This change of direction is known as refraction.,The law of reflection：（反射定律）The reflected ray lies in the plane of incidenceThe angle of reflection equals the angle of incidence，namely,The law of refraction：（折射定律） The refracted ray lies in the plane of incidenceFor a certain pair o

15、f media，the ratio between the sine of the angle of incidence and that of the angle of refraction is a constant regardless of the value of the incident angle，namelywhere is the relative refractive index of the second medium with respect to the first medium,1.3 Refractive Index and Speed of Light（折射率和

16、光速）,The absolute refractive indices of the first and second media are given by,The absolute refractive indices of the vacuum is 1,The law of ray path reversibility:the path of light propagation can be studied along the actual traveling direction of the ray or along its reversed direction,and the res

17、ults are exactly the same.,reflection,refraction,1.4.1 Reversibility of Ray Paths,1.4 Reversibility of Ray Paths and Total Internal Reflection（光路的可逆性和全反射）,Total internal reflection : When light travels from a medium with a higher refractive index to a medium with a lower refractive index and it stri

18、kes the boundary at more than the critical incident angle, (1 1C )all light will be reflected back to the incident medium, meaning it will not penetrate the second medium. The incident angle at which the angle of refraction equals 900 is called the critical incident angle, 1C. Total internal reflect

19、ion is a necessary condition to make optical fiber work as a communications link.,1.4.2 Total Internal Reflection（全反射）,when ,1.4.2 Total Internal Reflection（全反射）,There is an ang|e of incidence I0 that will make the angle of refraction I2 equal 900When I1I0,the refracted ray no longer exists,and the

20、incident ray is totally reflected.I0 is called the critical angle.,totally reflection:higher refractive index lower refractive index,Critical angle and TIR临界角和全反射定律,Exercise,example：Light from a water medium with n=1.33 is incident upon a total reflection prism at an angle of 900. The glass index is

21、 1.50. Total reflection will happen?,The phenomenon of total internal reflection is widely used in optical instruments,(b) a measurement of the refractive index of a medium,(a) a reflective prism can replace a mirror to reduce energy loss,Application of total internal reflection（全反射的应用）,Fermat Lemma

22、（费马引理）,optical path:The optical path is defined as the product of light through the geometric distance in the medium and the refractive index of the medium.,Fermat Lemma（费马引理）,Fermat Lemma： Light propagate from one point to another point according the extremum propagation path.(most possibility mini

23、mum),Introduction to Fermat,Pierre de Fermat (17 August 1601 12 January 1665) was a French lawyer at the Parlement of Toulouse, southern France, and a mathematician. Many people see him as the father of modern calculus. His method of finding the biggest and smallest ordinates of curved lines also ma

24、kes him a contributor to differential calculus, which was not known at that time. His studies in the theory of numbers give him the rank of the founder of the modern theory. He also made notable contributions to analytic geometry and probability. He is also famous for making a simple mathematical st

25、atement (known as Fermats Last Theorem) that he said he could prove, but he never wrote down his proof. Mathematicians tried to prove it for hundreds of years before finally managing it. Fermat probably did not really have a proof for this theorem, and only thought he did.,vertify the refraction law

26、 with the Fermat Lemma（费马引理证明折射定律）,is the incident angle,is the refraction angle,1.5 Classification of Optical System and Concept of Imaging（光学系统分类和成像概念）,All kinds of optica are designed and manufactured for various purposesThe elements (mirror,lens,prism.et) are combined in a certain way to meet th

27、e requirements of a specific application.,the optical system of a military telescope consisting of two lens gruops (the objective and the eyepiece)and two prisms,Optical system of a military telescope（军事望远镜的光学结构）,symmetrical systems: lens systems have a symmetry revolution axis.spherical system:an o

28、ptical system containing only elements of spherical surfaces.(a plane surface can be regarded as a spherical surface with an infinite radius )lenses:Lenses can be classified into two categories according to their shapesThe first is converging lens.The second is diverging lens.,Symmetrical systems, s

29、pherical system and lenses（共轴系统，球面系统和透镜）,the effects of a beam propagating through a lens according to the principles of ray and wave propagation.,converging lens（会聚透镜）,For an ordinary lens with spherical surfaces,the corresponding ray bundle will no longer intersect at a single point,but normally t

30、he rays will approximately converge toward a point.For a negative lens,a virtual image point can be presented.,diverging lens（发散透镜）,Any object of certain boundary or volume can be regarded as comprising millions of lightemitting pointsAn image point is obtained for each of these points and the aggre

31、gate of all the image points is called the image of the object obtained.The object lies in the object space,the image lies in the image space,Principle of imaging（成像原理）,1.6 Ideal Images and Ideal Optical Systems（理想成像和理想光学系统）,（理想成像要求）The most common requirement for an imaging optical system is that i

32、ts image should be clear.Every object point corresponds to a single and unique image point.,a system provide perfect imaging as follow:1、A line is imaged as a line,Imaging of line（直线成像）,2、A plane is imaged as a plane,Imaging of plane（平面成像）,An optical system with the pointtopoint，lineto-line and plan

33、etoplane imaging characteristics in its object and image spaces is known as an ideal optical system，and the image that it produces is known as an ideal imageFor a symmetrical ideal optical system(1)the image of the optical axis must lie on the same axis，and the image of an object point in a plane co

34、ntaining the optical axis must lie in the same plane.,轴上点成像在轴上,过光轴任意截面成像性质相同,(2) The image of any object in a single plane perpendicular to the optical axis is proportional to the object.,(3)the imaging properties of a symmetrical ideal optical system can be represented by these known conjugate planes and conjugate point.The principal planes and the principal points of the symmetrical system,