共查询到17条相似文献，搜索用时 78 毫秒
1.
涡旋光束的产生、传输与应用是当前光学领域热门的研究课题之一.本文提出的新型多环涡旋光束,包括双环涡旋及三环涡旋光束,它是由多束携带不同拓扑电荷数且束腰半径不同的拉盖尔-高斯涡旋光束共轴叠加而成,其光强分布为多环结构.从理论上研究了多环涡旋光束的形成与分布特征,基于共轭对称延拓Fourier计算全息方法生成了多环涡旋光束的计算全息图,并利用一个空间光调制器实验产生了与理论一致的高质量的多环涡旋光束.研究表明多环涡旋光束的各环携带不同的轨道角动量,空间分布保持相互独立.这种新型的多环涡旋光束相对于携带单一拓扑电荷数的涡旋光束,提供了更多的控制参数和更加多样化的结构分布,因此在光学镊子、光学捕获等微操控以及光通信领域具有潜在的应用潜力. 相似文献
2.
在研究光楔衍射法产生单涡旋的基础上,基于长条形光楔阵列,提出了利用光束阵列衍射产生涡旋阵列的方法.该方法要求光束阵列在平行于光楔边缘方向上的光束间距等于光束直径的整数倍.利用超精密机床采用一体化加工法加工了光楔阵列元件,验证了该方法的可行性.利用空间光调制器快速灵活调整光束阵列的优点,搭建了借助空间光调制器加载达曼光栅衍射产生所需光束阵列的实验光学系统.针对光束阵列与光楔阵列的匹配问题,研究了达曼光栅掩模图基本单元对光束阵列的调控,获得了可调结构的光束阵列.实验产生了拓扑荷一致的光学涡旋阵列,与仿真结果相一致,证明所提方法的有效性. 相似文献
3.
光学涡旋的产生、传输与应用是当前光学领域的研究热点之一.光学涡旋具有轨道角动量,作为一种全新的自由度,丰富了目前光通信的方式.利用面向目标的共轭对称延拓傅里叶计算全息技术,基于空间光调制器,用单束激光直接产生混合光模式阵列进行编码通信.采用由单光涡和复合光涡构成的4种易于识别的模式组成2×2混合光模式阵列,进行灰度图像的编码传输.在接收端提取混合光模式阵列图的信息并进行解码,实现零误码的灰度图像再现.以传输一幅Lena图像为例,使用2×2混合光模式阵列进行编码通信,相对于传统单光涡编码通信,其信息容量可增加4倍.该方法光路简单易行,可扩展性强,进一步拓展使用4×4混合光模式阵列进行编码通信,信息容量提升16倍.提出的混合光模式阵列编码通信方法对于提高信息传输容量具有重要价值. 相似文献
4.
5.
6.
平面涡旋光干涉的分析 总被引：1，自引：0，他引：1
光学涡旋具有独特的相位奇点和螺旋相位结构, 多个涡旋光场之间的干涉呈现出新颖的强度和相位分布特征.通过在平面波背景中嵌入涡旋相位产生平面涡旋光场, 采用数值模拟方法研究了多个平面涡旋光场之间的干涉, 并分析了两个平面涡旋光场的中心间距及拓扑荷值对涡旋产生和湮灭的影响.进一步数值研究了对称分布的多个点涡旋光之间的干涉, 结果表明通过改变涡旋光束数目或者拓扑荷值, 可获得不同分布的对称涡旋阵列光场.利用计算全息并通过空间光调制器, 实验上实现了具有不同拓扑荷值的多个对称点涡旋光场的干涉, 其干涉图样与模拟结果吻合.实验结果不仅证实了数值模拟结果, 也为实验研究复杂涡旋光场的干涉提供了一种有效方法. 相似文献
7.
设计了基于光学涡旋相移技术的离面位移测量实验方案,实现了电子散斑干涉中相移的数字控制.该方法利用输入液晶空间光调制器中的叉形光栅产生涡旋光束,通过涡旋光束绕轴的旋转产生相移;同时,产生的涡旋光束又作为参考光与物光干涉.实验中,在物体发生离面位移前后依次输入四幅叉形光栅,产生相移步长为π/2的涡旋光束,利用CCD获得涡旋光与物光的干涉光场,从而获得离面位移场的包裹相位;再通过解包裹,获得物体离面变形的相位变化.光学涡旋相移法可应用于离面位移测量. 相似文献
8.
从理论和实验上研究涡旋光束通过具有费马螺线分布微孔结构的衍射板后拓扑荷数的变化情况,以及光束强度分布的衍射和聚焦特性。利用一个正透镜对衍射光束进行聚焦,观察和研究聚焦光束在焦平面后一定范围内的光强分布变化情况。衍射光束的最内环光强分布在束腰前后约有五个变化阶段。这一变化趋势适用于涡旋光束通过微孔沿不同费马螺线分布的衍射板的情况,无论是螺线旋转方向的改变,还是螺线结构数目的改变。通过衍射光束与球面波的干涉来验证拓扑荷数的变化规律。结果表明,这种衍射可以产生新的拓扑荷数,其变化与入射涡旋光束的相位波前和螺旋微孔阵列的相对旋向有关。 相似文献
9.
10.
针对涡旋光束检测范围局限这一问题, 提出了一种新的光学涡旋拓扑荷值检测方法-单环多段光强分布检测法, 它以分段数和环半径为两大检测常数, 将检测涡旋光束拓扑荷值范围扩大到了128种, 与以往利用旁瓣调控光学涡旋检测拓扑荷值方法相比, 检测范围扩大了1个数量级. 单环多段光强分布是基于计算机全息图实现在远场衍射焦平面上环半径相等的两束携带不同拓扑荷数的涡旋光束叠加后形成的光强分布. 计算机模拟和光学实验验证了所提出方法的可行性, 该方法在自由空间光通信领域具有一定的研究价值和应用潜力. 相似文献
11.
12.
A new method of generation of two dimensional vortex lattices is described. In this method, different parts of the wavefront are given different local tilts to realize vortex lattice in the propagated field. These linear phase variations corresponding to tilts in different locations of the wavefront are created using a spatial light modulator (SLM). The diffracted field from the SLM is found to contain vortex lattice and the presence of these vortices is confirmed experimentally. Computational results are also provided. 相似文献
13.
We propose the generation of novel composite vortex beams by coaxial superposition of Laguerre–Gaussian (LG) beams with common waist position and waist parameter. Computer-generated holography by conjugate-symmetric extension is applied to produce the holograms of several composite vortex beams. Utilizing the holograms, fantastic light modes including optical ring lattice, double dark-ring and double bright-ring composite vortex beams etc. are numerically reconstructed. The generated composite vortex beams show diffraction broadening with some of them showing dynamic rotation around beam centers while propagating. Optical experiments based on a computer-controlled spatial light modulator (SLM) verify the numerical results. These novel composite vortex beams possess more complicated distribution and more controllable parameters for their potential application in comparison to conventional optical ring lattice. 相似文献
14.
We demonstrate a technique for making copies of optical vortices with the same topological charge using a single spatial light modulator. It has been shown that by using suitable diffractive optical elements, several copies of optical vortices with the same topological charge could be created. We have devised diffractive optical elements using a single spatial light modulator which could be used to make a vortex and its copies without inverting the charge. The nature of the topological charge was investigated with the interferometric technique. The experimental results are verified with the theoretical analysis. We anticipate that our results may find applications ranging from optical manipulation to quantum information. 相似文献
15.
Filippus S. Roux 《Optics Communications》2010,283(24):4855-4858
Stochastic (i.e. random and quasi-random) optical fields may contain distributions of optical vortices that are represented by non-uniform topological charge densities. Numerical simulations are used to investigate the evolution under free-space propagation of topological charge densities that are inhomogeneous along one dimension. It is shown that this evolution is described by a diffusion process that has a diffusion parameter which depends on the propagation distance. 相似文献
16.
Xinzhong LI;Liuhao ZHU;Haihao FAN;Wenjun WEI;Xin MA;Xueyun QIN;Huajie HU;Yuping TAI 《光子学报》2022,51(7):253-260
Since the invention of the laser in the 1960s, the higher power of the laser has led to a better understanding of the interaction between light and matter because of its monochromaticity, directionality, and coherence. Optical tweezers, which won the 2018 Nobel Prize in Physics, are one of the best applications of lasers. In 1976 ASHKIN A discovered that a single beam of light dependent on a gradient force could capture particles. The single beam optical tweezers is widely used in the biological field. In 1992, Orbital Angular Momentum （OAM） was discovered, structural beams carrying OAM have been widely used in the field of particle manipulation and it adds the degree of freedom of lateral manipulation for optical tweezers and has more abundant manipulation modes. However, in the case of the existing structural beams, no matter how the structure of light is changed, due to the nature of OAM, its structure beam will always make particles move along a given orbit in specific applications. The real-time orbital movement of particles is not considered. Therefore, there is an urgent need for a beam with a more abundant mode than the previous single OAM, which can simultaneously exist a variety of different OAMs and control the motion of particles in real-time. The Hohmann transfer was derived by the German engineer Dr. Walter Hohmann in 1925. It is a method to transfer the minimum energy of a satellite between two circular orbits with the same inclination and different altitudes. It’s widely used in the aerospace field. Although particles move in solution, they are also affected by buoyancy and other external forces in addition to the gravity of particles themselves, and the environment they live in is relatively complex, so their motion cannot be compared with the law of planetary motion. However, the orbital switching of Hohmann transfer can still solve the existing problems of structured optical tweezers.To solve this situation, in this paper, the corresponding orbit beam is generated by beam shaping technology, the orbit is transformed into an elliptical orbit by coordinate transformation technology, and finally, the orbit is combined by the Fourier phase shift theorem. A kind of Hohmann Transfer Structured Beam （HTSB） has been proposed via combining beam shaping technology, coordinate transformation technology and Fourier phase shift theorem. This beam has a very abundant mode of regulation and the phase gradient distribution can transfer the particles from the parking orbit to the synchronous orbit. Also, the size, structure, and phase gradient, can be arbitrarily adjusted, in the application can be based on the actual needs of the corresponding adjustment of the beam. Firstly, we analyze the relationship between each orbit of Hohmann transfer, and give the relationship between parameters corresponding to each orbit of HTSB, and the control method. The intensity and phase distribution of the HTSB with increasing radius are simulated. Secondly, we extend the HTSB according to the principle of Hohmann transfer, and discuss the parameter setting and generation method of HTSB with more orbits. The intensity and phase distribution of HTSB with more orbits are simulated. Finally, an optical tweezer experiment is set up, and the HTSB is used to manipulate the polystyrene particles. We have designed two experiments, the first experiment is using a fixed HTSB to make the particles from the parking orbit transfer to synchronous orbit, and the second experiment is using dynamic switch cover template on spatial light modulator particles in a week and a half after parking orbits respectively, choose an appropriate time to transfer orbit switch mask template, rotating again after a week and a half, Transfer to synchronous orbit and rotate once in synchronous orbit. Moreover, the beam can do a lot more. It can reverse the fixed orbit and the synchronous orbit by changing the topological charges; the velocity of particles moving between orbits can be controlled by adjusting the topological charge of each orbit; it can control the way the particles are transferred by rotating the beam as a whole. Therefore, this research proves the feasibility of Hohmann transfer in the microscopic field and has great significance in the field of optical micromanipulation. 相似文献
17.
提出了一种基于基元全息图频谱分析的计算全息参考光角度选择方法.通过分析基元全息图的空间频谱成分,导出全息图正确再现需要满足的约束条件;求解了基于空间光调制器的计算全息再现系统的参考光角度取值范围;用N-LUT算法计算了成像距离为1 000mm时,一幅22.5mm×26.1mm的二维图像取不同参考光角度时的全息图,并进行了数字再现和光学再现实验.结果表明:参考光角度在0.893 8°到1.398 0°之间选择可以获得质量良好的再现像;参考光角度小于0.893 8°时,再现像与共轭像不能完全分离,参考光角度大于1.398 0°时,全息图频率过高会造成欠采样,导致再现像与下一级共轭像互相交叠.实验现象与理论分析一致,验证了参考光夹角选择方法的正确性. 相似文献