平面波圆环光阑衍射的边界衍射波理论

根据Maggi-Rub inowic边界衍射波理论和亥姆霍兹-基尔霍夫积分定理,给出了平面波圆环边界衍射波积分公式.圆孔、圆屏衍射以及轴上光场分布可作为其特例得到.分析了衍射场的轴上光强分布特点.数值计算比较表明,使用文中所给公式与直接用基尔霍夫衍射积分公式作数值计算的结果完全一致,而在近场使用瑞利衍射积分与文中结果有较大差异.     

Composite optical vortices in noncollinear Laguerre--Gaussian beams and their propagation in free space

Taking two Laguerre-Gaussian beams with topological charge 1 = ±1 as an example, this paper studies the composite optical vortices formed by two noncollinear Laguerre-Gaussian beams with different phases, amplitudes, waist widths, off-axis distances, and their propagation in free space. It is shown by detailed numerical illustrative examples that the number and location of composite vortices at the waist plane are variable by varying the relative phase β, amplitude ratio η, waist width ratio ξ, or off-axis distance ratio μ. The net topological charge lnet is not always equal to the sum lsum of charges of the two component beams. The motion, creation and annihilation of composite vortices take place in the free-space propagation, and the net charge during the propagation remains unchanged and equals to the net charge at the waist plane.     

Coherence vortices of partially coherent beams in the far field

Based on the propagation law of cross-spectral density function, studied in this paper are the coherence vortices of partially coherent, quasi-monochromatic singular beams with Gaussian envelope and Schell-model correlator in the far field, where our main attention is paid to the evolution of far-field coherence vortices into intensity vortices of fully coherent beams. The results show that, although there are usually no zeros of intensity in partially coherent beams with Gaussian envelope and Schell-model correlator, zeros of spectral degree of coherence exist. The coherence vortices of spectral degree of coherence depend on the relative coherence length, mode index and positions of pairs of points. If a point and mode index are kept fixed, the position of coherence vortices changes with the increase of the relative coherence length. For the low coherent case there is a circular phase dislocation. In the coherent limit coherence vortices become intensity vortices of fully coherent Laguerre--Gaussian beams.     

拉盖尔-高斯模叠加而成的部分相干光的相干涡旋

对Bogatyryova等人近来提出的一种可分离位相的部分相干光的相干涡旋作了详细研究.这类新的光束由相同角向指数的拉盖尔-高斯(LG)模非相干叠加而成.研究表明，叠加LG模式的模指数，权重因子和参考点位置的选择都会影响圆刃型位错出现的位置，使得涡旋消失或出现多个相干涡旋.而且，LG模叠加而成的位相不可分离的部分相干光也存在相干涡旋. 关键词： 奇点光学 一类新的部分相干光束 相干涡旋 圆刃型位错     

准行波半导体光放大器的简化模型

从理论上提出了一个针对准行波半导体光放大器(TWSOA)的简化功率行波方程模型.通过数值分析给出了简化模型的适用范围.结果表明:在放大器两个端面反射率均小于10-3时,简化模型的计算相对误差不超过5%,而这也是简化模型的适用范围;放大器的工作点离阈值越远,则简化模型的计算相对误差也越小,反之则越大;在适用范围内,简化模型在计算效率上最多可以比原始模型提高30%左右.     

Vortex solitons in the semi-infinite gap of optically induced periodic lattices

Vortex solitons with a ring vortex core residing in a single lattice site in the semi-infinite gap of square optical lattices are reported. These solitons are no longer bound states of the Bloch-wave unit (Bloch-wave distribution in one lattice site) at the band edge of the periodic lattice, and consequently they do not bifurcate from the corresponding band edge. For saturable nonlinearity, one family of such solitons is found, and its existing curve forms a closed loop, which is very surprising. For Kerr nonlinearity, two families of such vortex solitons are found.     

F-P半导体光放大器的频率响应特性

从描述F-P型半导体光放大器(FPSOA)中光子与载流子相互作用的行波速率方程出发,利用小信号分析法得到了光腔内部前、后向光场的微扰量的微分方程组,并利用其分析了FPSOA的频率响应特性。计算结果表明:FPSOA具有高通的频率响应特性。所得结论与已有文献报道的实验结果符合较好。     

非傍轴矢量高斯光束的圆屏衍射

利用矢量瑞利衍射积分公式，推导出非傍轴矢量高斯光束圆屏衍射的解析表示式.非傍轴矢量高斯光束圆屏衍射的轴上场分布、远场表示式、自由空间中的传输公式，以及傍轴近似下高斯光束圆屏衍射的菲涅耳和夫琅禾费衍射公式可以作为一般公式的特例统一处理.数 值计算和比较实例说明了非傍轴矢量高斯光束的光强分布和远场特性.分析表明，在圆屏衍 射中，f参数和截断参数决定光束的非傍轴行为. 关键词： 传输光学 非傍轴矢量高斯光束 圆屏衍射 矢量瑞利衍射积分公式     

离轴位相奇点的动态传输

推导出高斯背景的离轴位相奇点光束的半屏衍射解析公式,详细研究了离轴位相奇点的动态传输.结果表明,半屏衍射,偏移量和传输距离都会影响位相奇点的传输行为和衍射场位相奇点的分布.改变偏移量和传输距离,衍射场伴随有位相奇点的产生,移动和湮没. 关键词： 奇点光学 离轴位相奇点光束 半屏衍射 光涡漩     

Spatial correlation properties and phase singularity annihilation of Gaussian Schell-model beams in the focal region

By using the generalized Debye diffraction integral, this paper studies the spatial correlation properties and phase singularity annihilation of apertured Gaussian Schell-model （GSM） beams in the focal region. It is shown that the width of the spectral degree of coherence can be larger, less than or equal to the corresponding width of spectral density, which depends not only on the scalar coherence length of the beams, but also on the truncation parameter. With a gradual increase of the truncation parameter, a pair of phase singularities of the spectral degree of coherence in the focal plane approaches each other, resulting in subwavelength structures. Finally, the annihilation of pairs of phase singularities takes place at a certain value of the truncation parameter. With increasing scalar coherence length, the annihilation occurs at the larger truncation parameter. However, the creation process of phase singularities outside the focal plane is not found for GSM beams.