AnIntroductiontoNonlinearOptics()

1、Nonlinear OpticsTextbooks: (1)钱士雄，王恭明钱士雄，王恭明非线性光学非线性光学-原理与进展原理与进展复旦大学复旦大学 (2)石顺祥石顺祥非线性光学非线性光学西安电子科技大学出版社西安电子科技大学出版社 (3)叶佩弦叶佩弦非线性光学物理非线性光学物理北京大学出版社北京大学出版社 (4)李淳飞李淳飞非线性光学非线性光学电子工业出版社电子工业出版社 (5) Robert W. Boyd, Nonlinear Optics， 3rd Edition (6) Y. R. Shen, Nonlinear opticsIntroduction1.What is nonlinea

2、r Optics and the development history of nonlinear optics2. Material Response to the Light 3. Classification of nonlinear optical effects4. Wide applications ( Optics (from 16th century to 1960) a) The nature of optics(the properties of waves and particles) (electromagnetic field theory and quantized

3、 theory on light) b) Interaction between light and matter (only linear interaction before the laser was invented)1.What is nonlinear Optics?Linear OpticsThe output is proportional to the input field and no interactions and energy transfer between waves with different frequencies, which originate fro

4、m the linear polarization of the medium.P = e e0 c cEThe absorption and refraction index keep constant with the intensity and frequency of the input light.Light travels indepently in the linear materialsNonlinear OpticsP = e e0 c c(1)E + e e0 c c(2)EE + e e0 c c(3)EEE + For the input field with very

5、 high intensity that are comparable with the intensity of average Coulomb field of the light atom, the polarization of the medium must be written as:This nonlinear polarization can result in lots of nonlinear optical effects which will be learned in this course.The very early nonlinear optics(before

6、 the birth of laser)Pockels effect :1893 by F. C. Pockels (Germany) Linear dependence of the refractive index on the intensity of the electric field Electrooptical effectEnanisotropyisotropyglass,Elliptically polarized beamKerr effect: 1875 by John Kerr Electrooptical Kerr effect Electrically induce

7、d birefringence that is proportional to the square of the electric field Linearly polarized beamElliptically polarized beamglass2anisotropyisotropyglass,En VJohn Kerr FRS (1824 1907) , Scottish physicistAn effect in which a very strong linearly polarized light field produces anisotropy in the refrac

8、tive index of an isotropic medium, usually a liquid. Optical Kerr effect:Linearly polarized beamKerr cellPumping beamby C. V. Raman in 1928. Raman Effect:the scattering of light by matter, accompanied by a noticeable change in the frequency of the scattered light. Nobel Prize in 1930Brillouin scatte

9、ring named after Lon Brillouin, occurs when light in a medium (such as air, water or a crystal) interacts with time-dependent optical density variations and changes its energy (frequency) and path. by Lon Nicolas Brillouin in 1922.C. V. Raman(1888-1970) Indian physicistLon Nicolas Brillouin(1889-196

10、9)Franch physicistThe nonlinear optics developed slowly for the lack of experimental conditions before the birth of laser! Stimulated emission, The MASER and The LASER (1917) The concept of stimulated emission Albert Einstein (1928) Observation of negative absorption or stimulated emission near to r

11、esonant wavelengths, Rudolf Walther LadenburgH. Kopfermann and R. Ladenburg, Experimental Proof of Negative Dispersion, Nature Volume 122, 438-439 (22 September 1928) hE1E2AbsorptionE1E2hSpontaneous Emission E1E2hhhStimulated EmissionLASER(MASER)Light (Microwave) Amplification by Stimulated Emission

12、 of Radiation The Maser （Microwave Amplification by Stimulation Emission of Radiation）Two groups were working on Maser in 1950sAlexander M. Prokhorov and Nikolai G. Basov (Lebedev institute of Moscow)Charles H. Townes, James P. Gordon and Herbert J. Zeiger (Colombia University) Shared the Nobel Phys

13、ics Prize in 1964 The LASER (1951) V. A. Fabrikant “A method for the application of electromagnetic radiation (ultraviolet, visible, infrared, and radio waves)” patented in Soviet Union. (1958) Townes and Arthur L. Schawlow, “Infrared and Optical Masers,” Physical Review (1958) Gordon Gould definiti

14、on of “Laser” as “Light Amplification by Stimulated Emission of Radiation” (1960) Schawlow and Townes U. S. Patent No. 2,929,922 *(1960) Theodore Maiman Invention of the first Ruby Laser (1961) Ali Javan The first He-Ne Laser Theodore Maiman1927-2007American engineer and physicist Properties of Lase

15、r BeamA laser beam is intense is coherent has a very low divergence can be compressed in time up to few femto seconds Applications of Laser Medicine, Research, Industry, Military, Communication, Art, Information technology, Entertainment, *Strong coherent light source for nonlinear optical effectsTh

16、e development of nonlinear opticsI: 19611965 new phenomenon of NLO SHG, DF,SF,OPA, SFII: 19651969 nonlinear optical spectrum, transient nonlinear optics, and new NLO devices were designedIII: 1970now widely and fully developed NLO medium: from solid medium to gas/atom evaporation/liquid and even to

17、solid crystals NLO orders: from 2nd order to 3rd, 5th or even high order harmonic effectsNLO types: from common non-resonant NLO to resonant NLOTime domain: from ms, ns to ps, fs, and even to as Ruby laserQuartzPrism694.3nm347.2nm694.3nmSHGP. A. Franken, A. E. Hill, C. W. Peters, and G. Weinreich,Ge

18、neration of Optical Harmonics, Phys. Rev. Lett. 7, 118, 19611961 Kaiser and Garrett: Two-photon absorption (TPA)1962 Optical Sum Frequency (SF)31212312zTRQ-switchingKerr cellRuby laserPRnitrobenzeneStimulated Raman Scattering (SRS)Stokes line1965 Optical Parametric Amplification Optical Parametric O

19、scalitionStimulated Brillium Scattering (SBS)In the early and middle of 1960s, Bloembergen and his students built up the basic theory of nonlinear optics based on the medium polarization and coupled waves.Nicolaas Bloembergen Nobel Prize in Physics (1981) Under high input intensity, Self-Focusing fo

20、rms 1964年预言并观察到光子回波 1967年发现了光学自感应透明 1969年预言并观测到光学章动 1972年观察到光学自由感应衰减研究物质在共振条件共振条件下受到强相干光场强相干光场作用时，在小于物质内部纵向及横向弛豫时间的时域范围内所发生的光学现象。诸如光子回波、光学自由感应衰减、光学章动、自感应透明等等。 瞬态相干效应瞬态相干效应瞬态相干光学效应瞬态相干光学效应目前主要应用在固体和气体介质中共振谱线增宽性质的研究和激发态弛豫参量的测量。 70年代初开始非线性光学的应用研究：一方面给非线性光学注入了持续发展的动力；另一方面研究成果进一步丰富了非线性光学的内容。扩展相干光源扩展相干光源

21、倍频、和频、多倍频： 蓝光、紫光、紫外光 差频：红外激光 参量振荡：可见光、近红外、红外、远红外 可调谐激光器 受激Raman散射、四波混频、参量振荡（气体）：紫外光、真空紫外光可调谐激光器 相位共轭技术相位共轭技术 四波混频、受激布里渊散射四波混频、受激布里渊散射 消除光束传播过程中的相位畸变，提高成像质量 消除激光器内元件的畸变及热效应，改善激光输出质量光计算、光通信及光电子技术光计算、光通信及光电子技术 光学逻辑器件 （与、或、非、与非） 光调制器（半导体中的非线性等） 光存储器（光子回波时域相干光子存储） 光纤通信、光孤子、光学压缩态光谱与物质研究中的非线性光学方法光谱与物质研究中的非

22、线性光学方法（开创者：Bloembergen、肖洛-激光光谱，1981年诺贝尔物理学奖） 饱和吸收光谱 双光子吸收光谱 相干瞬态光谱 四波混频光谱 表面与表面吸收的检测非线性光学晶体材料非线性光学晶体材料: 我国处于国际领先地位，其中偏硼酸钡（BBO ）和三硼酸锂（LBO）、氟代硼铍酸钾 （KBBF）三种晶体为我国发现并批量生长，他们性能优良，开创了激光紫外倍频的新纪元。 世界上第一个“中国牌”的非线性晶体新材料晶体BBO于1984年问世，这是中国科学院福建物质结构研究所首创的非线性光学晶体材料。 倍频效率高，抗光损伤能力最高，调谐宽度最宽的优质紫外倍频晶体。激光器里最常用的三种类型非线性光学

23、晶体是BBO、LBO和KTP。前两者是中国发明，后者为美国杜邦公司发明，但足够大尺寸的KTP也是在中国生长出的。KBBF晶体是目前中国独有的技术，是吸收边最短的深紫外晶体（200nm）。 1990年以来，非线性光学在如下领域取得了重大进展：年以来，非线性光学在如下领域取得了重大进展： 飞秒非线性光学性质的研究，以及飞秒化学和飞秒生物学 有源、无源半导体器件在光通信中的应用 大容量、高速光存储 X激光器 压缩态的实验进展 非线性光学技术已经成为高科技，尤其是光电子技术、光子学、光子技术、纳米材料等学科的基础。 非线性光学现在已经是光学一个非常重要的学科分支，内容涵盖了各种非线性光学效应以及激光和

24、物质相互作用及其应用等领域。 随着科学研究的不断深入，目前的主要任务仍然是在揭示新的非线性光学现象、探索其产生机制、特点以及应用。Introduction1.What is nonlinear Optics and the development history2. Material Response to the Light 3. Classification of nonlinear optical effects4. Wide applications ( DBJDHBE0ttEJHBPEDmme00022002trEEeemMaxwell Eqs. and Material Eqs.

25、2. Material Response to the Light Linear optics wave equation:If the nonlinear effect can not be ignored, the wave equation is rewritten as follows,22200022NLrPttm e emEEwhere, P=PL+PNL.So the nonlinear polarization PNL is the origin of the new optical field .Material Response to the Light (scalar a

26、ssumption)P = e e0 c c( (1)E + e e0 c c( (2)EE + e e0 c c( (3)EEE + P: induced polarization of mediume e0: dielectric constant of vacuumE: electric fieldc c( (1) : first-order susceptibilityD = e e0E + P = e eE In linear optics: n2 = 1 +c c( (1)Wuhan UniversityIn generalaE1)2()3()1()2(ccccwhere is t

27、he intensity of average Coulomb field of the lighter atom, its value is aboutaEcmV /108Nonlinear Terms Second-order term, c c( (2)EE and typical second order nonlinear optical effects1.Supposing input field is monochromatic, E=(1/2)E()e-it+c.c. c(2)E2 static voltage appears across the sample c(2)E2

28、cos(2t) second harmonic generation(SHG) 2.Two input frequencies 1 1,2 2 E=E1(1)e-i1t+E2(2)e-i2t +c.c. c(2) E1(1) E2(2)cos(1 2)t sum frequency (SF) c(2) E1(1) E2*(2)cos(1 2)t difference frequency (DF)P = e e0 c c( (1)E + e e0 c c( (2)EE + e e0 c c( (3)EEE + 3. Optical parametric oscillation (OPO) Opt

29、ical parametric amplification (OPA)Input two waves with s and p (s p) i p- s idle frequency s p i the signal light can be amplified OPA OPO = OPA + ResonatorFor powerful pump lightDF processThird-order term, c c(3)EEE and typical effectsc(3)(3) E() E()3 3 cos(3(3t) ) 3rd harmonic gernerationFour wav

30、e mixing 1( )( )2 ( ) ( )3 n = n0+n2I stimulated Raman scattering (SRS)self-focusing and self phase modulationoptical Kerr effect (OKE)saturation absorption (SA)two (twin)- photon absorption (TPA)Introduction1.What is nonlinear Optics and the development history of nonlinear optics2. Material Respon

31、se to the Light 3. Classification of nonlinear optical effects4. Wide applications ( 3. Classification of nonlinear optical effectsNonlinear optical effects can be divided into two classes:(1) parametric interaction effects The energies are transferred only between the waves, e.g., SHG, THG, OPA, OP

32、O, FWM, DFWM, (2) non-parametric interaction effects The energies are transferred between waves and also between the wave and matter. e.g., SA, TPA, SRS, SBS, Introduction1.What is nonlinear Optics?2. Material Response to the Light 3. Classification of nonlinear optical effects4. Wide applications (

33、 Sending infrared light into a crystal yielded this display of green light: Nonlinear optics allows us to change the color of a light beam, to change its shape in space and time, to switch telecommunication systems, and to create the shortest events ever made by Man.Nonlinear Optics produces many ex

34、otic effects and has wide applications.wide applications (VISIBLEUVIRFIRVUVMW-raysX-rays(1) Nonlinear optical effects new methods to have new coherent lightwide applications ()()()()()(2121)()(nnncEEEP1n 2(2) surface physics and surface SHG)()(/)(222sNLsssPce2c4E(2) surface physics and surface SHG (continued)a) to detect the molecular orienta