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1、2011年技术物理学院08级（激光方向）专业英语翻译重点！作者：邵晨宇Electromagnetic电磁的principle原则principal主要的macroscopic宏观的microscopic微观的differential微分vector矢量scalar标量permittivity介电常数photons光子oscillation振动density of states态密度dimensionality维数transverse wave横波dipole moment偶极矩diode二极管mono-chromatic单色temporal时间的spatial空间的velocity速度wave

2、 packet波包be perpendicular to线垂直 be nomal to线面垂直isotropic各向同性的anistropic各向异性的vacuum真空assumption假设semiconductor半导体nonmagnetic非磁性的considerable大量的ultraviolet紫外的diamagnetic抗磁的paramagnetic顺磁的antiparamagnetic反铁磁的ferro-magnetic铁磁的negligible可忽略的conductivity电导率intrinsic本征的inequality不等式infrared红外的weakly doped弱

3、掺杂heavily doped重掺杂a second derivative in time对时间二阶导数vanish消失tensor张量refractive index折射率crucial主要的quantum mechanics量子力学transition probability跃迁几率delve研究infinite无限的relevant相关的thermodynamic equilibrium热力学平衡（动态热平衡）fermions费米子bosons波色子potential barrier势垒standing wave驻波travelling wave行波degeneracy简并converg

4、e收敛diverge发散phonons声子singularity奇点（奇异值）vector potential向量式partical-wave dualism波粒二象性homogeneous均匀的elliptic椭圆的reasonable公平的合理的reflector反射器characteristic特性prerequisite必要条件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曲率半径convention管理hyperbole双曲线hyperb

5、oloid双曲面radii半径asymptote渐近线apex顶点rigorous精确地manifestation体现表明wave diffraction波衍射aperture孔径complex beam radius复光束半径lenslike medium类透镜介质be adjacent to与之相邻confocal beam共焦光束a unity determinant单位行列式waveguide波导illustration说明induction归纳symmetric对称的steady-state稳态be consistent with与之一致solid curves实线dashed cu

6、rves虚线be identical to相同eigenvalue本征值noteworthy关注的counteract抵消reinforce加强the modal dispersion模式色散the group velocity dispersion群速度色散channel波段repetition rate重复率overlap重叠intuition直觉material dispersion材料色散information capacity信息量feed into注入derive from由之产生semi-intuitive半直觉intermode mixing模式混合pulse duration

7、脉宽mechanism原理dissipate损耗designate by命名为to a large extent在很大程度上etalon标准具archetype圆形interferometer干涉计be attributed to归因于roundtrip一个往返infinite geometric progression无穷几何级数conservation of energy能量守恒free spectral range自由光谱区reflection coefficient（fraction of the intensity reflected）反射系数transmission coeffic

8、ient（fraction of the intensity transmitted）透射系数optical resonator光学谐振腔unity归一optical spectrum analyzer光谱分析grequency separations频率间隔scanning interferometer扫描干涉仪sweep移动replica复制品ambiguity不确定simultaneous同步的longitudinal laser mode纵模denominator分母finesse精细度the limiting resolution极限分辨率the width of a transmi

9、ssion bandpass透射带宽collimated beam线性光束noncollimated beam非线性光束transient condition瞬态情况spherical mirror 球面镜locus（loci）轨迹exponential factor指数因子radian弧度configuration不举intercept截断back and forth反复spatical mode空间模式algebra代数in practice在实际中symmetrical对称的a symmetrical conforal resonator对称共焦谐振腔criteria准则concentr

10、ic同心的biperiodic lens sequence双周期透镜组序列stable solution稳态解equivalent lens等效透镜verge 边缘self-consistent自洽reference plane参考平面off-axis离轴shaded area阴影区clear area空白区perturbation扰动evolution渐变decay减弱unimodual matrix单位矩阵discrepancy相位差longitudinal mode index纵模指数resonance共振quantum electronics量子电子学phenomenon现象explo

11、it利用spontaneous emission自发辐射initial初始的thermodynamic热力学inphase同相位的population inversion粒子数反转transparent透明的threshold阈值predominate over占主导地位的monochromaticity单色性spatical and temporal coherence时空相干性by virtue of利用directionality方向性superposition叠加pump rate泵浦速率shunt分流corona breakdown电晕击穿audacity畅通无阻versatile用

12、途广泛的photoelectric effect光电效应quantum detector量子探测器quantum efficiency量子效率vacuum photodiode真空光电二极管photoelectric work function光电功函数cathode阴极anode阳极formidable苛刻的恶光的irrespective无关的impinge撞击in turn依次capacitance电容photomultiplier光电信增管photoconductor光敏电阻junction photodiode结型光电二极管avalanche photodiode雪崩二极管shot n

13、oise 散粒噪声thermal noise热噪声精选文档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

14、photons，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，我们讨论麦克斯韦方程和他们显示的有关

15、光在真空中传播的问题。我们介绍了光子的概念以及光子态密度。由于态密度是很重要的属性，不单对光子而言，我们会经常用到态密度。我们将在之后用态密度描述其他（准）粒子包括降维系统。此外，我们介绍各种粒子态的占有率。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 reaso

16、nable 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 ferromagneti

17、c contributions 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

18、.Furthermore,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 d

19、oes Zn1-yMnySe.精选文档 现在我们讨论麦克斯韦方程组问题。这样我们原则上可以使用方程的一般形式如方程（1,1）但是我们仍要对半导体进行一些合理的假设：我们假设没有宏观自由空间电荷而且是非磁性物质。其实所有的物质具有一定的抗磁性。但是对于10-6的数量级来说这个影响很小可以忽略不计。顺磁性特别是铁磁性对低频的贡献特别大。然而这些贡献会在高频率时迅速减弱。所以假设为非磁性材质在电磁频谱的可见光波段范围内对铁磁性物质具有良好的近似。此外比较常见的半导体不是铁，含铁或反铁磁性物质，而且具有一个小的集中顺磁性中心和稳定的光学性质。唯一例外的是半导体含有相当数量的如锰或铁离子比如Zn1-yM

20、nySe。1. For intrinsic or weakly doped semiconductors,the carrier density is small and consequently is as well.Then the following inequality holds.对于本征半导体或者弱掺杂半导体而言，载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 li

21、near relation 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 dielectri

22、c function and the susceptiility,respectively.They can be considered as linear response functions. 这种线性关系就是为什么下面所有都被归为线性光学的原因。线性关系是人们通常在没有更精确信息时假定两个物理量之间的关系。原则上我们也可以将（1.26a）即P（E）对于E的幂级数展开式看做截止后线性项，和的数量分别被称为介电函数和磁化率。它们可以被看作是线性响应函数。1. The longitudinal waves which we found in matter are not electromagn

23、etic waves 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.

24、This interface 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.我们在物质中发现纵波不是电磁波而是与E和P的纯偏振波与其他相反的消失的D,B,H。到目前为止，我们正在考虑多数

25、媒介的光特性。这种介质边界需要一些额外的考虑，比如真空（空气）和半导体之间的接口。这个接口对光的反射至关重要。在这里我们指出边界条件只允许一种表面模式，即波沿界面传播并且双方场振幅指数衰减。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 disc

26、uss this 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

27、 so we shall 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.精选文档态密度是量子力学中对粒子特性来说很关键的一个量。比如可以用费米黄金法则计算概率。我们将在不同维度系统d=3.2.1中讨论这个问题。我们需要这些结

28、果为了之后的低维半导体结构。对于态密度的讨论，特别是各个方面的，我们不能笼统的当成谐振子对待，所以我们在这个问题上需要花更多的时间并且钻研更多的细节。在本部分结束时，我们要陈述经典粒子如费米子和波色子在热力学平衡状态时的占有率。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). 如果假设有一个无限高势垒围绕的区域，那么波函数必须在壁有节点（图1.3a）。1. A

29、nother approach 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.另一种做法是外加周期性边界条件。如图1.3b所示平面波在腔体的边界上会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 n

30、egative values 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 d

31、irection of 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

32、.70),values 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 -

33、polarizations (see above).在对照驻波时，我们必须分别考虑ni 的正负值。这个步骤的结果最终会是相同的态密度。其结果我们发现平面波在k-空间直角坐标系所有轴上具有恒定的密度。我们经常需要知道的是在k方向上k到k+dk壳内的状态数目。这个问题可以通过引入k-空间极坐标来解决。在d维K-空间中壳为微分量dVk和dk的关系由(1.72)可知。根据不同的边界条件我们求k值或者ni值只考虑正值（1.67）或正负值（1.70）。k-空间中极坐标下k到k+dk之间的状态数D(K)等于每个状态值除以dVk乘以gs。gs量为简并度如自旋简并度。对于光子而言根据+偏振和-偏振有g= 2（见

34、上文）。10. We want 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.我们在这里强调的是，我们只假设是平面波但是没有假设是哪种粒子代

35、表的平面波光子，电子等等。因此这个结果对所有由平面波描述的粒子都有效。精选文档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 particl

36、es,Boltzmann statistics 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

37、Boltzmann constant 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 sta

38、tes D(E) and the 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

39、 other words,a macroscopic 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 poten

40、tial is zero for quanta whose number is not conserved,for e.g.,photons or phonons.我们需要的下一个量是上面讨论过的状态占有率。我们限定在下热力学平衡中。有三种统计方式：经典粒子统计，可区分粒子统计，玻耳兹曼统计。（1.80a）对于波色子来说，即具有整数自旋的不可区分粒子，比如光子，必须用波色-爱因斯坦统计（1.80b）费米子，或半整数自旋的不可区分粒子，例如电子必须服从费米-狄拉克统计fFD（1.80c）玻尔兹曼常数kB和化学势是这个系统增加一个粒子所必须增加的平均能量。对于费米子也称为费米能EF。找到一个在间隔

41、在E和E+dE之间的粒子的概率由态密度D(E)和占据概率f（1.81）而得。图1.5为fB,fBE和fFD随(E-)/kBT变化的曲线。玻耳兹曼统计数据表明这众所周知的指数依赖关系。费米- 狄拉克统计同状态粒子不能超过一个，从而实现泡利的不相容原理。玻色 -爱因斯坦凝聚，或者说具有宏观数量达到单个状态。如果落在一个有限态密度区域。在这种情况下能量类型E =和E必须分别考虑。此外由图1.5可见，在（E-）/KBT1时FBE和FFD收敛于FB。化学能为0的量子数量不守恒，例如声子或光子。12. A closely related topic of fundamental importance in

42、 laser electronics 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 a

43、lso the form of 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.精选文档一个与激光电子学中根本重要性有密切相关的议题就是光束传播。这些光束采取局部能量密度的类平面波的性质，贴近传播轴传

44、播合理的传播距离。激光振荡器的输出由一个或者多个光束组成。这也是由两个弧形反射谐振腔形成的电磁能量场的形式。对于这些模式特点的认识是许多激光现象研究的先决条件。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.在激光电子束和量子电子束最常用的碰撞形

45、成的垂直于传播方向的平面强度分布是高斯分布。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.我们因此将其称为光束的光斑尺寸。参数W0是光斑尺

46、寸的最小值。它是平面z=0时的光斑尺寸。公式（2.25）中的参数R(z)是在z的近球形波振面的曲率半径。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 W0a

47、nd its location-that is,the plane z=0-are specified.关于R（z）符号的约定是如果曲率中心在zz,则为负，反之亦然。一旦最小光斑尺寸W0的大小和位置确定，则根据方程（2.5）基本高斯光束的形式也唯一确定。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 s

48、pread (diffract) in the far field (公式) according to (2.29). 根据公式（2.29）最后的结果是波衍射的严格表示为波将被限制在孔半径为W0的横向方向的远场传播。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 .

49、A universal measure 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.光学振荡器，如它的低频、射频、微波部分，主要被用作在一个稳定功率输入的情况下生成一个强场。品质因数Q 是谐振器性能的通用衡量指标因为在谐振器中储存的磁能等于电能。18.The main difference between an optical resonator

50、and a microwave resonatorfor 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

51、 ,10-4cm , so the resonator is likely to have typical dimensions that are very large in comparison to the wavelength .精选文档光学振荡器和微波振荡器的不同之处在于，如：在=1cm(=3*1010 Hz)的条件工作下，后一种情况可以很容易的制造出相当于固有尺寸的振荡器。这导致了一个或少许共振在我们关心的区域存在。然而在光学范畴，10-4cm，这样振荡器的固有尺寸相比于波长可能非常巨大。19. This objection is overcome to a large extent

52、 by the use of open resonators , 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 conse

53、quently posses a very low 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.使用开放式的振荡器可以很大程度

54、的避免这种缺陷，它本质上是由一对相对着的平面或是曲面反射镜而构成。在这种振荡器中绝大部分的能量模式不会以直角的方式传播到镜子，因此能量是单程损失的。这些模式因此具有很低的Q值。如果是曲面镜，如下所示，少量存在的模式将在近轴处具有能量；因此在边缘处的衍射损耗与其他的损耗比起来可被忽略，如镜子的透射率。20. The FabryPerot etalon , or interferometer , named after its inventors can be considered as the archetype of the optical resonator . It consists of

55、 a planeparallel plate of thickness L and index n which is immersed in a medium of index n .法布里 - 珀罗标准具或干涉仪，以其发明者的名字命名，被认为是光学振荡器的原型。他有一个厚度为l折射率是n的平行平板组成，其所处的外界环境的折射率为n。21. The phase delay between two partial waveswhich is attributable to one additional round tripis given ,according to Figure 3.2,by两

56、部分之间的波的相位延迟的产生是由于增加了一个反射，根据图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 如果允许标准具中存在损失，我们会发现，传输的峰值小于1。将每通的部分强度损

57、失作为（1-A），我们发现，从联合来看传播衰减23. 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 lengt

58、h variation dl(3.20)where 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 . T

59、he optical signal to be 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 sig

60、nal . In the application it is important that the spectral width of the signal beam be smaller than the intermode spacing of the etalon (c/2nl) so that the ambiguity due to simultaneous transmission through more than one transmission peak can be avoided . For the same reason the total length scan is

61、 limited to dl/2n . Figure 3.5 demonstrates the operation of a scanning FabryPerot etalon ; Figure 3.6 shows intensity versus frequency data obtained by analyzing the output of a multimode HeNe laser oscillating near 6328A . The peaks shown correspond to longitudinal laser modes , which will be disc

62、ussed in Section 3.5 .精选文档根据3.15式，法布里 - 珀罗标准具出现最高传输率时，3.19为方便起见，取垂直入射（=0），可得下式3.20，在给定的峰值传输率下共振频率中dv的变化由长度的变化dl决定3.20其中v是内膜频率间隔由3.17给出。根据3.20，我们可以以半波长的长度调整标准具峰值传输频率v。这个性质可以用来操作标准具使它成为扫描干涉仪。通过标准具的长度被不断的扫频来分析光信号。如果传输峰值的宽度小于入射光信号光谱的光谱细节，标准具的输出将会形成与信号频谱相同的轮廓。在应用中很重要的一点是信号光的光谱宽度要小于标准具内模间距(c/2nl),这样由于不止一个

63、峰值传输的平行传输所造成的歧化就可以被避免。同样的原因，中长度的条件为dl/2n。图3.5示范了扫描法布里 - 珀罗标准具的运作；图3.6展示了通过分析一个震荡在6328A的多模氦氖激光的输出，由频率的数据获得强度。这个峰值显示出相当于纵向激光模式，我们将在3.5章进一步讨论。24.It is clear from the foregoing that when operating as spectrum analyzer the etalon resolutionthat is , its ability to distinguish details in the spectrumis li

64、mited by finite width of its transmission peaks . If we take ,somewhat arbitrarily , the limiting resolution of the etalon as the separation v1/2 between the two frequencies at which the transmission is down to half its peak value .由上可知，当作为标准具粉刺暗绿频谱分析仪来使用时，它的分辨能力在频谱细节上是有限的，由其传输峰值限制了宽度。如果我们任取标准具的极限分辨

65、率为量频率间隔v1/2这样传输为峰值的一半。25. The finesse F (which is used as a measure of the resolution of FabryPerot etalon ) is , according to (3.24) , the ratio of the separation between peaks to the width of a transmission bandpass . This ratio can be read directly from the transmission characteristics such as those of Figure 3.4 , for which we obtain F26.精细度F（用来作为法布里 - 珀罗标准具分辨率的度量使用）根据3.24是传输带通宽度峰值的间隔比率。这个比率可以直接从传输特性得到比如图3.4可以看出F2626. As a practical note we may add that the finesse , as d