激光專業(yè)英語

1、2011年技術(shù)物理學(xué)院08級（激光方向）專業(yè)英語翻譯重點！作者：邵晨宇Electromagnetic電磁的principle原則principal主要的macroscopic宏觀的microscopic微觀的differential微分vector矢量scalar標(biāo)量permittivity介電常數(shù)photons光子oscillation振動density of states態(tài)密度dimensionality維數(shù)transverse wave橫波dipole moment偶極矩diode二極管mono-chromatic單色temporal時間的spatial空間的velocity速度wave

2、 packet波包be perpendicular to線垂直 be nomal to線面垂直isotropic各向同性的anistropic各向異性的vacuum真空assumption假設(shè)semiconductor半導(dǎo)體nonmagnetic非磁性的considerable大量的ultraviolet紫外的diamagnetic抗磁的paramagnetic順磁的antiparamagnetic反鐵磁的ferro-magnetic鐵磁的negligible可忽略的conductivity電導(dǎo)率intrinsic本征的inequality不等式infrared紅外的weakly doped弱

3、摻雜heavily doped重?fù)诫sa second derivative in time對時間二階導(dǎo)數(shù)vanish消失tensor張量refractive index折射率crucial主要的quantum mechanics量子力學(xué)transition probability躍遷幾率delve研究infinite無限的relevant相關(guān)的thermodynamic equilibrium熱力學(xué)平衡（動態(tài)熱平衡）fermions費米子bosons波色子potential barrier勢壘standing wave駐波travelling wave行波degeneracy簡并converg

4、e收斂diverge發(fā)散phonons聲子singularity奇點（奇異值）vector potential向量式partical-wave dualism波粒二象性homogeneous均勻的elliptic橢圓的reasonable公平的合理的reflector反射器characteristic特性prerequisite必要條件quadratic二次的predominantly最重要的gaussian beams高斯光束azimuth方位角evolve推到spot size光斑尺寸radius of curvature曲率半徑convention管理hyperbole雙曲線hyperb

5、oloid雙曲面radii半徑asymptote漸近線apex頂點rigorous精確地manifestation體現(xiàn)表明wave diffraction波衍射aperture孔徑complex beam radius復(fù)光束半徑lenslike medium類透鏡介質(zhì)be adjacent to與之相鄰confocal beam共焦光束a unity determinant單位行列式waveguide波導(dǎo)illustration說明induction歸納symmetric對稱的steady-state穩(wěn)態(tài)be consistent with與之一致solid curves實線dashed cu

6、rves虛線be identical to相同eigenvalue本征值noteworthy關(guān)注的counteract抵消reinforce加強the modal dispersion模式色散the group velocity dispersion群速度色散channel波段repetition rate重復(fù)率overlap重疊intuition直覺material dispersion材料色散information capacity信息量feed into注入derive from由之產(chǎn)生semi-intuitive半直覺intermode mixing模式混合pulse duration

7、脈寬mechanism原理dissipate損耗designate by命名為to a large extent在很大程度上etalon標(biāo)準(zhǔn)具archetype圓形interferometer干涉計be attributed to歸因于roundtrip一個往返infinite geometric progression無窮幾何級數(shù)conservation of energy能量守恒free spectral range自由光譜區(qū)reflection coefficient（fraction of the intensity reflected）反射系數(shù)transmission coeffic

8、ient（fraction of the intensity transmitted）透射系數(shù)optical resonator光學(xué)諧振腔unity歸一optical spectrum analyzer光譜分析grequency separations頻率間隔scanning interferometer掃描干涉儀sweep移動replica復(fù)制品ambiguity不確定simultaneous同步的longitudinal laser mode縱模denominator分母finesse精細(xì)度the limiting resolution極限分辨率the width of a transmi

9、ssion bandpass透射帶寬collimated beam線性光束noncollimated beam非線性光束transient condition瞬態(tài)情況spherical mirror 球面鏡locus（loci）軌跡exponential factor指數(shù)因子radian弧度configuration不舉intercept截斷back and forth反復(fù)spatical mode空間模式algebra代數(shù)in practice在實際中symmetrical對稱的a symmetrical conforal resonator對稱共焦諧振腔criteria準(zhǔn)則concentr

10、ic同心的biperiodic lens sequence雙周期透鏡組序列stable solution穩(wěn)態(tài)解equivalent lens等效透鏡verge 邊緣self-consistent自洽reference plane參考平面off-axis離軸shaded area陰影區(qū)clear area空白區(qū)perturbation擾動evolution漸變decay減弱unimodual matrix單位矩陣discrepancy相位差longitudinal mode index縱模指數(shù)resonance共振quantum electronics量子電子學(xué)phenomenon現(xiàn)象explo

11、it利用spontaneous emission自發(fā)輻射initial初始的thermodynamic熱力學(xué)inphase同相位的population inversion粒子數(shù)反轉(zhuǎn)transparent透明的threshold閾值predominate over占主導(dǎo)地位的monochromaticity單色性spatical and temporal coherence時空相干性by virtue of利用directionality方向性superposition疊加pump rate泵浦速率shunt分流corona breakdown電暈擊穿audacity暢通無阻versatile用

12、途廣泛的photoelectric effect光電效應(yīng)quantum detector量子探測器quantum efficiency量子效率vacuum photodiode真空光電二極管photoelectric work function光電功函數(shù)cathode陰極anode陽極formidable苛刻的惡光的irrespective無關(guān)的impinge撞擊in turn依次capacitance電容photomultiplier光電信增管photoconductor光敏電阻junction photodiode結(jié)型光電二極管avalanche photodiode雪崩二極管shot n

13、oise 散粒噪聲thermal noise熱噪聲1. In this chapter we consider Maxwells equations and what they reveal about the propagation of light in vacuum and in matter. We introduce the concept of photons and present their density of states.Since the density of states is a rather important property，not only for phot

14、ons，we approach this quantity in a rather general way. We will use the density of states later also for other(quasi-) particles including systems of reduced dimensionality.In addition,we introduce the occupation probability of these states for various groups of particles. 在本章中，我們討論麥克斯韋方程和他們顯示的有關(guān)光在真空

15、中傳播的問題。我們介紹了光子的概念以及光子態(tài)密度。由于態(tài)密度是很重要的屬性，不單對光子而言，我們會經(jīng)常用到態(tài)密度。我們將在之后用態(tài)密度描述其他（準(zhǔn)）粒子包括降維系統(tǒng)。此外，我們介紹各種粒子態(tài)的占有率。1. Now we treat Maxwells equations in matter.Doing so we have in principle to use the equations in their general from the equation (1.1).However we will still make some assumptions which are reasonabl

16、e for semiconductors:we assume that there are no macroscopic free space charges and that we have a nonmagnetic material.Actually,all matter has some diamagnetism.But this is a rather small effect of the order of 10-6so it can be neglected for our purposes.Paramagnetic and especially ferromagnetic co

17、ntributions can be significantly larger for low frequencies.However,even these contributions diminish rapidly for higher frequencies.Consequently the assumption of a nonmagnetic material is a good approximation in the visible range of the electromagnetic spectrum even for ferromagnetic materials.Fur

18、thermore,the more common semiconductors are not ferro-,ferri- or antiferromagnetic and have only a small concentration of paramagnetic centres with negligible influence on the optical properties.The only exceptions are semiconductors which contain a considerable amount of e.g.,Mn or Fe ions as does

19、Zn1-yMnySe. 現(xiàn)在我們討論麥克斯韋方程組問題。這樣我們原則上可以使用方程的一般形式如方程（1,1）但是我們?nèi)砸獙Π雽?dǎo)體進(jìn)行一些合理的假設(shè)：我們假設(shè)沒有宏觀自由空間電荷而且是非磁性物質(zhì)。其實所有的物質(zhì)具有一定的抗磁性。但是對于10-6的數(shù)量級來說這個影響很小可以忽略不計。順磁性特別是鐵磁性對低頻的貢獻(xiàn)特別大。然而這些貢獻(xiàn)會在高頻率時迅速減弱。所以假設(shè)為非磁性材質(zhì)在電磁頻譜的可見光波段范圍內(nèi)對鐵磁性物質(zhì)具有良好的近似。此外比較常見的半導(dǎo)體不是鐵，含鐵或反鐵磁性物質(zhì)，而且具有一個小的集中順磁性中心和穩(wěn)定的光學(xué)性質(zhì)。唯一例外的是半導(dǎo)體含有相當(dāng)數(shù)量的如錳或鐵離子比如Zn1-yMnySe。1.

20、For intrinsic or weakly doped semiconductors,the carrier density is small and consequently is as well.Then the following inequality holds.對于本征半導(dǎo)體或者弱摻雜半導(dǎo)體而言，載流子密度小因此也小，那么下面的不等式成立。1. This linear relation is the reason why everything that is treated in the following is called linear optics.A linear rel

21、ation is what one usuallyassumes between two physical quantities as long as one does not have more precise information.In principle we can also consider (1.26a) as an expansion of P(E) in a power series in E which is truncated after the linear term,The quantities and are called the dielectric functi

22、on and the susceptiility,respectively.They can be considered as linear response functions. 這種線性關(guān)系就是為什么下面所有都被歸為線性光學(xué)的原因。線性關(guān)系是人們通常在沒有更精確信息時假定兩個物理量之間的關(guān)系。原則上我們也可以將（1.26a）即P（E）對于E的冪級數(shù)展開式看做截止后線性項，和的數(shù)量分別被稱為介電函數(shù)和磁化率。它們可以被看作是線性響應(yīng)函數(shù)。1. The longitudinal waves which we found in matter are not electromagnetic wav

23、es but pure polarization waves with E and P opposed to each other with vanishing D,B and H.Until now we were considering the properties of light in the bulk of a medium.The boundary of this medium will need some extra consideration e.g.,the interface between vacuum (air) and a semiconductor.This int

24、erface is crucial for reflection of light.Here we only want to state that the boundary conditions allow a surface mode, that is,a wave which propagates along the interface and had field amplitudes which decay exponentially on both sides.我們在物質(zhì)中發(fā)現(xiàn)縱波不是電磁波而是與E和P的純偏振波與其他相反的消失的D,B,H。到目前為止，我們正在考慮多數(shù)媒介的光特性。這

25、種介質(zhì)邊界需要一些額外的考慮，比如真空（空氣）和半導(dǎo)體之間的接口。這個接口對光的反射至關(guān)重要。在這里我們指出邊界條件只允許一種表面模式，即波沿界面?zhèn)鞑ゲ⑶译p方場振幅指數(shù)衰減。1. A quantity which is cruial in quantum mechanics for the properties of particles is their density of states.It enters,e.g.,in Fermis folen rule which allows one to calculate probabilities.We want to discuss this

26、 problem in a general way for systems of different dimensionalities d=3,2 and 1.We shall need these results later on for low-dimensional semiconductor structures.The discussion of the density of states,especially in various dimensions,is not so commonly treated as the harmonic oscillator,and so we s

27、hall spend some time on this problem and delve more into details.At the end of this section we shall also state the occupation probability in thermodynamic equilibrium for classical particles,for fermions and bosons.態(tài)密度是量子力學(xué)中對粒子特性來說很關(guān)鍵的一個量。比如可以用費米黃金法則計算概率。我們將在不同維度系統(tǒng)d=3.2.1中討論這個問題。我們需要這些結(jié)果為了之后的低維半導(dǎo)體結(jié)

28、構(gòu)。對于態(tài)密度的討論，特別是各個方面的，我們不能籠統(tǒng)的當(dāng)成諧振子對待，所以我們在這個問題上需要花更多的時間并且鉆研更多的細(xì)節(jié)。在本部分結(jié)束時，我們要陳述經(jīng)典粒子如費米子和波色子在熱力學(xué)平衡狀態(tài)時的占有率。1. If we assume that we have an infinitely high potential barrier around the box,then the wavefunction must have nodes at the walls (Fig.1.3a). 如果假設(shè)有一個無限高勢壘圍繞的區(qū)域，那么波函數(shù)必須在壁有節(jié)點（圖1.3a）。1. Another appro

29、ach is to impose periodic boundary conditions. Then the plane wave should have equal amplitude and slope on opposite sides of the cube according to Figure.1.3b.另一種做法是外加周期性邊界條件。如圖1.3b所示平面波在腔體的邊界上會有相同的振幅和斜率。1. In contrast to the case of standing waves,we now have to consider positive and negative valu

30、es of niseparately.This procedure results finally in the same density of sates.As a consequence we find that plane waves have in Cartesian coordinates in k-space a constane density on all axes.Often one wants to know the number of states in a shell between k and k+dk independent of the direction of

31、k. This question can be answered by introducing polar coordinates k-space.The differential volume dVk of a shell of thickness dk in a d-demensional k-space is given by (1.72).Depending on the boundary condition we have to take into account only positive (1.67),or positive and negative (1.70),values

32、of k or ni.The number D(k) of states in k-space found between k and k+dk in polar coordinates is given by dividing dVk by the volume for each state and by multiplying by gs.The quantitu g considers degeneracies such as the spin degeneracy.For photons we have g=2 according to the + and - polarization

33、s (see above).在對照駐波時，我們必須分別考慮ni 的正負(fù)值。這個步驟的結(jié)果最終會是相同的態(tài)密度。其結(jié)果我們發(fā)現(xiàn)平面波在k-空間直角坐標(biāo)系所有軸上具有恒定的密度。我們經(jīng)常需要知道的是在k方向上k到k+dk殼內(nèi)的狀態(tài)數(shù)目。這個問題可以通過引入k-空間極坐標(biāo)來解決。在d維K-空間中殼為微分量dVk和dk的關(guān)系由(1.72)可知。根據(jù)不同的邊界條件我們求k值或者ni值只考慮正值（1.67）或正負(fù)值（1.70）。k-空間中極坐標(biāo)下k到k+dk之間的狀態(tài)數(shù)D(K)等于每個狀態(tài)值除以dVk乘以gs。gs量為簡并度如自旋簡并度。對于光子而言根據(jù)+偏振和-偏振有g(shù)= 2（見上文）。10. We w

34、ant to stress here that we assumed only plane waves but did not make any specific assumptions about which type of particles are represented by these plane waves-photons,electrons etc.Therefore this result is valid for all particles described by plane waves.我們在這里強調(diào)的是，我們只假設(shè)是平面波但是沒有假設(shè)是哪種粒子代表的平面波光子，電子等等

35、。因此這個結(jié)果對所有由平面波描述的粒子都有效。11. The next quantity,which we need is the occupation probabiltiy of the states discussed above.We restrict ourselves in the following to thermodynamic equilibrium.There are three types of statistics which can be considered:For classical,distinguishable particles,Boltzmann sta

36、tistics apply:(1.80a).For bosons,i.e indistinguishable particles with integer spin,photones being an example,one must use the Bose-Einstein statistics (1.80b).Fermions,or indistinguishable particles with half-integer spin e.g.,electrons obey the Fermi-Dirac statistics fFD(1.80c).The Boltzmann consta

37、nt is kBand the chemical potential is which gives the average energy necessary to add one more partical to the system. For fermions is also known as the Fermienergy EF.The probability to find a particle in the interval from E to E+dE is then given by the product of the density of states D(E) and the

38、 occupation probability f (1.81).In figure.1.5 we plot fB,fBEand fFDas a function of (E-)/kBT.The Boltzmann statistics show the well-known exponential dependence.The Fermi-Dirac statistics never exceed one,realizing thus Paulis exclusion principle.The Bose-Einstein condensation,or in other words,a m

39、acroscopic population of a single state,if falls in a region with finite density of states.In this case the species with energies E= and those with E must be considered separately. Furthermore it is obvious from Figure 1.5 that fBEand fFDconverge to fBfor (E-)/kBT1.The chemical potential is zero for

40、 quanta whose number is not conserved,for e.g.,photons or phonons.我們需要的下一個量是上面討論過的狀態(tài)占有率。我們限定在下熱力學(xué)平衡中。有三種統(tǒng)計方式：經(jīng)典粒子統(tǒng)計，可區(qū)分粒子統(tǒng)計，玻耳茲曼統(tǒng)計。（1.80a）對于波色子來說，即具有整數(shù)自旋的不可區(qū)分粒子，比如光子，必須用波色-愛因斯坦統(tǒng)計（1.80b）費米子，或半整數(shù)自旋的不可區(qū)分粒子，例如電子必須服從費米-狄拉克統(tǒng)計fFD（1.80c）玻爾茲曼常數(shù)kB和化學(xué)勢是這個系統(tǒng)增加一個粒子所必須增加的平均能量。對于費米子也稱為費米能EF。找到一個在間隔在E和E+dE之間的粒子的概率由

41、態(tài)密度D(E)和占據(jù)概率f（1.81）而得。圖1.5為fB,fBE和fFD隨(E-)/kBT變化的曲線。玻耳茲曼統(tǒng)計數(shù)據(jù)表明這眾所周知的指數(shù)依賴關(guān)系。費米- 狄拉克統(tǒng)計同狀態(tài)粒子不能超過一個，從而實現(xiàn)泡利的不相容原理。玻色 -愛因斯坦凝聚，或者說具有宏觀數(shù)量達(dá)到單個狀態(tài)。如果落在一個有限態(tài)密度區(qū)域。在這種情況下能量類型E =和E必須分別考慮。此外由圖1.5可見，在（E-）/KBT1時FBE和FFD收斂于FB?；瘜W(xué)能為0的量子數(shù)量不守恒，例如聲子或光子。12. A closely related topic of fundamental importance in laser electroni

42、cs is the propagation of optical beams.These beams usually take the form of planelike waves whose energy density is localized,for reasonable propagation distances,near the propagation axis.The output of laser oscillators will be found to consist of one or more of such beams.This is also the form of

43、the fields set up by feeding electromagnetic energy into a resonator formed by two curved reflectors.The understandingof the characteristics of these modes is thus a prerequisite to the study of many laser-related phenomena.一個與激光電子學(xué)中根本重要性有密切相關(guān)的議題就是光束傳播。這些光束采取局部能量密度的類平面波的性質(zhì)，貼近傳播軸傳播合理的傳播距離。激光振蕩器的輸出由一個

44、或者多個光束組成。這也是由兩個弧形反射諧振腔形成的電磁能量場的形式。對于這些模式特點的認(rèn)識是許多激光現(xiàn)象研究的先決條件。13. The most widely encountered optical beam in laser electronics and quantam electronics is one where the intensity distribution at planes normal to the propagation direction is Guassian distribution.在激光電子束和量子電子束最常用的碰撞形成的垂直于傳播方向的平面強度分布是高斯分

45、布。14. We will consequently refer to it as the beam “spot size”.The parameter W0is the minimum spot size.It is the beam spot size at the plane z=0.The parameter R(Z) in equation (2.25) is the radius of curvature of the very nearly spherical wavefronts at z.我們因此將其稱為光束的光斑尺寸。參數(shù)W0是光斑尺寸的最小值。它是平面z=0時的光斑尺寸。

46、公式（2.25）中的參數(shù)R(z)是在z的近球形波振面的曲率半徑。15. The convention regarding the sign of R(z) is that it is negative if the center of curvature occurs at zz and vice versa.The form of the fundamental Gaussian beam is,according to equation (2.25),uniquely determined once its minimum spot size W0and its location-that

47、 is,the plane z=0-are specified.關(guān)于R（z）符號的約定是如果曲率中心在zz,則為負(fù)，反之亦然。一旦最小光斑尺寸W0的大小和位置確定，則根據(jù)方程（2.5）基本高斯光束的形式也唯一確定。16. This last result is a rigorous manifestation of wave diffraction according to which a wave that is confined in the transverse direction to an aperture of radius W0will spread (diffract) in

48、the far field (公式) according to (2.29). 根據(jù)公式（2.29）最后的結(jié)果是波衍射的嚴(yán)格表示為波將被限制在孔半徑為W0的橫向方向的遠(yuǎn)場傳播。17. Optical resonators , like their low-frequency , radio-frequency , and microwave counterparts , are used primarily in order to build up large field intensities with moderate power inputs . A universal measure

49、of this property is the quality factor Q of the resonator .Since the average magnetic energy stored in a resonator is equal to the electric energy.光學(xué)振蕩器，如它的低頻、射頻、微波部分，主要被用作在一個穩(wěn)定功率輸入的情況下生成一個強場。品質(zhì)因數(shù)Q 是諧振器性能的通用衡量指標(biāo)因為在諧振器中儲存的磁能等于電能。18.The main difference between an optical resonator and a microwave reso

50、natorfor example , one operating at =1cm(=3*1010 Hz)is that in the latter case one can easily fabricate the resonator with typical dimensions comparable to . This leads to the presence of one , or just a few , resonances in the region of interest . In the optical regime , however ,10-4cm , so the re

51、sonator is likely to have typical dimensions that are very large in comparison to the wavelength .光學(xué)振蕩器和微波振蕩器的不同之處在于，如：在=1cm(=3*1010 Hz)的條件工作下，后一種情況可以很容易的制造出相當(dāng)于固有尺寸的振蕩器。這導(dǎo)致了一個或少許共振在我們關(guān)心的區(qū)域存在。然而在光學(xué)范疇，10-4cm，這樣振蕩器的固有尺寸相比于波長可能非常巨大。19. This objection is overcome to a large extent by the use of open reso

52、nators , which consist essentially of a pair of opposing flat or curved reflectors . In such resonators the energy of the vast majority of the modes does not travel at right angles to the mirrors and will thus be lost in essentially a single traversal . These modes will consequently posses a very lo

53、w Q . If the mirrors are curved , the few surviving modes will , as shown below , have their energy localized near the axis ; thus the diffraction losses caused by the open sides can be made small compared with other loss mechanisms such as mirror transmission.使用開放式的振蕩器可以很大程度的避免這種缺陷，它本質(zhì)上是由一對相對著的平面或是

54、曲面反射鏡而構(gòu)成。在這種振蕩器中絕大部分的能量模式不會以直角的方式傳播到鏡子，因此能量是單程損失的。這些模式因此具有很低的Q值。如果是曲面鏡，如下所示，少量存在的模式將在近軸處具有能量；因此在邊緣處的衍射損耗與其他的損耗比起來可被忽略，如鏡子的透射率。20. The FabryPerot etalon , or interferometer , named after its inventors can be considered as the archetype of the optical resonator . It consists of a planeparallel plate o

55、f thickness L and index n which is immersed in a medium of index n .法布里 - 珀羅標(biāo)準(zhǔn)具或干涉儀，以其發(fā)明者的名字命名，被認(rèn)為是光學(xué)振蕩器的原型。他有一個厚度為l折射率是n的平行平板組成，其所處的外界環(huán)境的折射率為n。21. The phase delay between two partial waveswhich is attributable to one additional round tripis given ,according to Figure 3.2,by兩部分之間的波的相位延遲的產(chǎn)生是由于增加了一個反射

56、，根據(jù)圖3.2，由22. If we allow for the existence of losses in the etalon medium , we find that the peak transmission is less than unity . Taking the fractional intensity loss per pass as (1-A) , we find that the transmission drops from unity to 如果允許標(biāo)準(zhǔn)具中存在損失，我們會發(fā)現(xiàn)，傳輸?shù)姆逯敌∮?。將每通的部分強度損失作為（1-A），我們發(fā)現(xiàn)，從聯(lián)合來看傳播衰減2

57、3. According to (3.15) , the maximum transmission of a FabryPerot etalon occurs when (3.19)Taking , for simplicity , the case of normal incidence (=0) , we obtain the following expression for the change dv in the resonance frequency of a given transmission peak due to a length variation dl(3.20)wher

58、e v is the intermode frequency separation as given by (3.17) . According to (3.20) ,we can tune the peak transmission frequency of the etalon by v by changing its length by half a wavelength . This property is untilized in operating the etalon as a scanning interferometer . The optical signal to be

59、analyzed passes through the etalon as its length is being swept . If the width of the transmission peaks is small compared to that of the spectral detail in the incident optical beam signal , the output of the etalon will constitue a replica of the spectral profile of the signal . In the application it is important that the spectral widt