1.The group's activities in this area have concentrated on the mechanical

effects of angular momentum on a dielectric and on the quantum properties of orbital angular momentum.

在这个研究领域,这个研究组主要集中在电介质中的角动量的机械效应和轨道角动量的量子属性。

2. Experimental realization of entanglement have been restricted to

two-state quantum systems. In this experiment entanglement exploiting the orbital angular momentum of photons, which are states of the electromagnetic field with phase singularities (doughnut modes).

纠缠的实验认识还只停留在二维量子系统。在这实验中,利用了光子的轨道角动量的纠缠是具有相位奇点(暗中空模式)的电磁场的状态。

3. Laguerre Gaussian modes with an index l carry an orbital angular momentum of per photon for linearly polarized light that is distinct from the angular momentum of the photons associated with their polarization

对线偏振光来说,具有因子l的LG模式的每个光子能携带 的轨道角动量,这是与偏振态相关的光子的角动量是截然不同的。

4. This opens up a practical approach to multi-dimensional entanglement where the entangled states do not only consist of two orthogonal states but of many of them. We expect such states to be of importance for the current efforts in the field of quantum computation and quantum communication.

它打开了一条通往多维纠缠态切实可行的通道,这纠缠态不仅存在于二维正交态中而且存在于多维正交态中。我们预料这纠缠态对于我们在量子计算和量子通信这个领域的努力是极其重要的

5. Given the experimental verification of the {orbital angular momentum conservation} one may expect to find entanglement between the two photons produced in the conversion process. Further experimental results show that the two-photon state goes beyond classical correlation and indeed we were able to prove the entanglement for photon states with phase singularities.

轨道角动量转换这个实验确认,人们可能发现纠缠存在于转换过程中的被诱导的两个光子中.进一步实验结果确认这两个光子的状态可能不存在经典的联系,我们确实能够证明具有相位奇点光子状态的纠缠。

6. The wave front (top) and the intensity pattern (bottom) of the simplest Laguerre Gauss ( ) or doughnut mode. The index l is referred to as the winding number and (p+1) is the number of radial nodes. The customary Gaussian mode can be viewed as LG mode with l=0.

最基本的LG( )和暗中空模式的波前(上)和强度图形(下)。L是径向回转数,p+1是径向波节数。普通的LG模可看作l=0的LG模。

7. The handedness of the helical wave fronts of the LG modes is linked to the sign of the index l and can be chosen by convention. The azimuthal phase term of the LG modes results in helical wave fronts. The phase variation along a closed path around the beam center is .

LG模的螺旋波前的左右手习惯是和l的特征相联系的,能够按规定进行选择。LG模的角向术语来源于螺旋波前,相变量沿着一条封闭路径绕光束中心一周就 .

8. "Optical vortices" might extract abundant information from matter, providing a new and potentially wide-ranging optical tool, a Spain-US team has proposed theoretically.

一个西班牙和美国团队从理论上提出,“光涡旋”可能从物质获得大量信息,从而提出了一个新的,潜在的广泛应用的光学工具。

9. An ordinary light beam, when viewed head-on, looks like a bright circle. But a special light beam called an "optical vortex," when viewed head-on, looks like a bright ring surrounding a dark central core,Optical vortices are the simplest kind of beam carrying a property called "orbital angular momentum".

一束普通的光,当我们迎面看时,就像一束明亮的圆周,但对于一束特殊的称作“光涡旋“的光束,我们迎面看时,像一个明亮的环绕着一个黑暗的圆心,这种光具有“轨道角动量”的属性,光涡旋是其中最简单的一种。

10. However, for light with orbital angular momentum (OAM), the energy spirals around the beam axis. Ordinary beams carry only "spin angular momentum," encoded in the polarization of light.

然而,对于具有轨道角动量(OAM)的光,其能量绕着光轴螺旋,普通的光仅仅携带“自旋角动量”,用光的偏振态进行编码。

11. All possible spin states can be constructed with just two polarization states (vertical and horizontal, or clockwise and counterclockwise).

所有的自旋状态都能用两个偏振态进行构建(垂直和水平,或者顺时针和逆时针)。

12.Around the dark core of an optical vortex, the energy flow carried by the light beam is like a spiral staircase, flowing in a clockwise or counterclockwise direction.

绕着光涡旋的黑暗中心,光束携带的能量流就像螺旋梯,沿着顺时针或者逆时针方向流动。

13. How an optical vortex reverses its spin: The laser beam propagates in the horizontal (z) direction and the transverse (x-y) plane is the cross-section of the beam at a given z-plane.

光涡旋怎样倒转它的自旋:在一个给定的z平面,激光沿水平z方向和横向的(x-y)平面的传播是光束的截面。

14. Mechanical properties of light like linear and angular momentum allow for the trapping, rotation and manipulation of microscopic objects.

线动量和角动量的机械特性有诱捕,旋转和对细微颗粒的操作。

15. A recent experiment shows that both the spin and the orbital angular momentum transferred to a small particle held off-axis are proportional to the local intensity of the beam .

最近的实验表明,传给远轴的小颗粒的自旋和轨道角动量是与光束的局部光强成比例。

16. Equivalently, if the light wave is circularly polarized (the electric field precesses in corkscrew fashion as the wave moves along) the two contrary states of the spin would then correspond to the light wave's electric field precessing clockwise (in a "right-handed" way) or anticlockwise (in a"left handed" way).

同理,如果光波是圆极化的(波移动时电场以螺旋形进动),自旋的两种相反的状态对应于光波电场以顺时针“右手”或逆时针方向“左手”进动。

17.For the purposes of data processing a 0 or 1 bit can be associated respectively with vertical and horizontal polarizations or, equivalently, with clockwise or anticlockwise polarizations.

为了处理数据,0,1分别和垂直和水平或者,同理,和顺时针和逆时针相关联。

18.The ordinary forward momentum of a particle of light is equal to Planck's constant divided by the wavelength of the equivalent light wave.

通常光子的前向动量等于普朗克常数除光波长。

19.The orientation or phase of a minute hand on a clock is the amount by which the hand has swept around the clock face: a quarter past the hour, half past the hour, etc.

一个钟表的分针的指向或相位就是分针绕表面扫过的量:一刻钟,半小时等等。

20.When a light pulse is made to follow a closed loop path in real space, the phase of the returning beam might be slightly off from the phase of light starting off at that point.

当一个光脉冲在一个真实的空间里沿着一个封闭的圆环运动,当它回到出发点时,其相位与刚出发时的相位可能会有些微的不同。

21.This disparity (which can result in an interference effect) can be modified by changing the path length. It can also be modified by changing the path geometry.

这不同(能够导致干涉效应)能够通过改变路径长度而得到修正,也可以通过改变几何路径而实现。

22.In other words, regions of the light wave that are "synchronized" or in the same phase (such as the portions of the wave with maximum electric field) trace out corkscrew-like patterns in the direction that the light beam travels.

换句话说,就是这样一个区域,同步的光波或具有相同相位(比如具有最大电场的部分)沿光线传播方向描绘出螺旋形的图样。

23.Light beams can carry both spin and orbital angular momentum (OAM) associated, respectively,with circular polarisation and the helicity of their phasefronts.

光能携带自旋角动量和轨道角动量(OAM),它们各自与圆偏振和相前的螺旋性有关。

24. Light carrying OAM can be described in terms of Laguerre-Gaussian (LG) modes which contain an exp(ilφ) phase term describing an on-axis phase singularity of strength l.

携带角动量的光能够用拉盖尔-高斯(LG)这个术语来描述。它包含一个exp(ilφ)相位术语,这个术语描述了长度为l的近轴相位奇点。

25. In addition to the number l, LG modes are characterised by their radial index p and their waist size w0.

除了l,LG模还可以用径向量子数P和腰长w0等特征参量来描述。

26. We encode and measure optical OAM via phase holograms. Phase holograms are typically designed to incorporate a spatially dependent phase retardation in the range 0 to 2π.

我们通过位相全息图来编码和测量轨道角动量,位相全息图在0到2π范围内合并空间独立相位延迟是具有代表性设计的。

27.Entanglement is one of the most puzzling and powerful properties of quantum theory and has received undiminished attention since the earliest days of quantum mechanics.

自从量子力学开创以来,纠缠是量子理论中最神秘最具强大特性的理论之一,媚力依旧。

28.Parametric down-conversion has proved a reliable tool for the generation of pairs of entangled photons 。

参量下转换已被证实成为产生一对纠缠光子的可靠的工具。

29.Here we will concentrate on a further entangled property, the orbital angular momentum of the two generated photons。

这儿,我们将进一步集中关注纠缠属性,还有两个产生的光子的轨道角动量。

30.The time entanglement arises from the energy conservation in the down-conversion process,which is expressed by the frequency matching condition.

时间纠缠来源于下转换过程中的能量守恒,下转换过程可以通过频率匹配条件来表示。

31.In this paper, we will show that the orbital angular momentum

entanglement, a transverse property of the beam,follows also directly from the phase-matching condition and is related to the conservation of orbital angular momentum.

在这篇文章中,我们将证明:轨道角动量的纠缠和光束的横向属性都直接来源于相位匹配条件,且和轨道角动量守恒是相关的。

32.Our approach differs from a recent theoretical paper that dealt with the possible conservation of the combined spin and orbital angular momentum in relation to the susceptibility of the down-conversion crystal.

我们的方法与新近一些理论文章提出的方法是不一样的,他们处理自旋角动量和轨道角动量可能的守恒当中涉及到了下转换晶体的磁化系数。

33.In the case of type I down-conversion, the polarization of the signal and the idler photons will be identical, its direction being determined by the polarization of the pump.

在第I类下转换情况下,信号光和闲频光的偏振是一样的,它们的方向是由泵浦光的偏振决定的。

34.In the case of type II down-conversion,the two down-converted photons have orthogonal polarizations.

在第II类下转换情况下,这两个下转换光子是正交偏振的。

35.Our analysis provides the theoretical background to a recent experiment, in which the conservation of the orbital angular momentum in parametric down-conversion has been observed for the first time。

我们的理论分析为近来的实验提供了理论支持,在最近的实验中,第一次在下参量转换中观察到了角动量守恒。

36.While the spin angular momentum describes the intrinsic photon spin and corresponds to the optical polarization of light, the orbital angular momentum is associated with the transverse phase front of a light beam.

自旋角动量描述了光的内禀自旋性以及相应的光的偏振,而轨道角动量是和光束的横向相前相联系的。

36.In the Schro¨dinger picture, the two photons in the signal and the idler mode are created by applying the operator a?/I> (k1)a?/I> (k2) to

the initial vacuum state u|0>, where k1,k2 is the transverse component

of the signal and idler wave vector, respectively. Similarly, k0 denotes the transverse component of the pump beam.

在薛定额绘景下,信号和闲频模式的两个光子通过引用算子a?/SPAN> (k1)a?/I> (k2)到初始真空状态u|0>而建立起来,这里k1,k2分别为信号和闲频波矢量的横向分量。同理,k0表示泵浦光的横向分量。

37.Previous work has shown that the OAM of a laser beam containing many photons in the same mode can be measured.

先前的工作已经证明,同一模式的包含许多光子的轨道角动量是能够测量的。

38.Such a device will allow us to take advantage of the increase in information capacity associated with orbital rather than spin angular momentum。

这样的装备将使我们充分利用轨道角动量而不是自旋角动量相联系的增加的信息容量。

39.Transfer of angular momentum from light to matter was proposed a long time ago by Beth as an effective tool to achieve the angular manipulation of macroscopic objects.

很早以前,Beth就提出了光与物质的角动量的转换,并作为一个有效的工具实现了对微颗粒的角向操作。

40.In Beth’s experiment the photon spin angular momentum was transferred to a quartz wave plate producing a tiny torque that was measured.

在Beth的实验中,光的自旋角动量被转移给石英波平面,并且生一个很小的力矩,这个很小的力矩能够被测量出来。

 

41.This new mechanism is more interesting for applications because it raises the possibility of optically aligning and manipulating both isotropic and anisotropic transparent bodies using, eventually, unpolarized light.

这个新的机械装置在应用上引起了越来越多的人的兴趣,因为它增加了在各向同性和各向异性介质中使用非偏振光进行光学娇正和操作的可能性。

42.Transfer of the orbital angular momentum of light to opaque particles was recently achieved using a laser beam oscillating in a high-order Laguerre-Gauss mode. Laguerre-Gauss laser beams, however, cannot transfer their orbital angular momentum to transparent materials .

最近在用高阶LG模振荡的激光束实现了轨道角动量对不透明颗粒的转移。然而不能实现对透明介质的转移。

43.Indeed, at present, no experiment is reported in the literature, in which the orbital angular momentum of photons is transferred to transparent bodies.

确实,当前还没有文章报道,在实验上实现了光子的轨道角动量在透明介质中的转移。

44.To see the meaning behind the new effect, we shall break the explanation into parts, considering in turn the issues of phase, orbital angular momentum in light, and then geometrical phase in light.

为了理解这个新现象背后的意思,我们分为几部分来解释,依次讨论相位,光的轨道角动量,然后是光的几何相位。

45.Liquid crystals were chosen because their strong birefringence provides a simple way to observe their rotation around the laser beam axis.

选择液晶是因为它们强烈的双折射提供了一种简单的方法去观察它们绕着激光光轴的旋转。

46. Moreover, NLCs are affected by both the spin and the orbital angular momentum of light, providing good material to check the total angular momentum conservation law.

而且,向列型液晶(NLCs)受到的光的自旋角动量和轨道角动量的影响,提供了一种好的材料去检验总角动量守恒定律。

47.We stress, however, that the material birefringence is not really important in our experiment, and that the same apparatus could be used, in principle, to optically manipulate isotropic transparent bodies also.

然而,我们强调,在我们的实验中,双折射材料并不是真正很重要的,在原理上,同样的仪器也可用于光学操纵各向同性透明介质。

48.Angular momentum has two key components: spin angular momentum and orbital angular momentum. The spin angular momentum of the earth is what gives us night and day: the earth spins and presents a changing face to the sun.

角动量有两个分量:自旋角动量和轨道角动量。地球的自旋角动量让我们有了白天和晚上,地球自转从而改变向着太阳的一面。

49 But Miles has been delving deeper and deeper into exactly how light behaves and how its unique properties can be better understood and put to use.

但是,Miles正对光钻研的越来越深入,研究光的确切行为和光的独特性质如何更好的理解并付诸应用。

50. Note that in light with orbital angular momentum, the direction of polarization (denoted by the direction of the arrow) does not change across the cross section. The fields only point up or down, with different phase delays in different places.

值得注意的是,具有轨道角动量的光,偏振方向(用箭头方向表示)在截面内部发生变化。只是在不同的地方由于不同相位延迟指上或指下。