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1.
We investigate a framework of an orbital angular momentum (OAM) entanglement swapping in a multi-dimensional Hilbert space with the spin angular momentum (SAM)-based orbital angular momentum (OAM) Bell-sate analysis. By the implementations of entanglement swapping with the SAM and OAM Bell-state measurements subsequently, the OAM entanglement states (qudits) are generated and then transferred between photons in multi-dimensional Hilbert space in a point-to-point fashion. In the proposed scheme, two pairs of the SAM-based OAM hybrid entanglement photons are deployed to conduct the successive SAM and OAM Bell-state measurements. It provides an alternative technique to transfer pure OAM Bell-states in qudits, which illustrates a possible experimental approach for devising a full repeater in a complex quantum computation network where entanglement swapping serves as a critical constituent. 相似文献
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光子既是经典信息也是量子信息的理想载体. 单个光子不仅可以携带自旋角动量(与光波的圆偏振相关), 还可以携带轨道角动量(与光波的螺旋相位相关). 而轨道角动量的重要意义在于可利用单个光子的量子态构建一个高维的Hilbert空间, 从而实现高维量子信息的编码. 自Allen等于1992年确认光子轨道角动量的物理存在以来, 轨道角动量在经典光学和量子光学领域展现了诸多诱人的应用前景, 目前已成为国际光学领域的研究热点之一. 本综述将着重介绍高阶轨道角动量光束的制备与调控技术, 特别是高阶轨道角动量的量子纠缠态操控、旋转Doppler 效应测量及其在远程传感和精密测量技术中的应用. 相似文献
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Jian Wang 《中国科学:物理学 力学 天文学(英文版)》2019,(3)
Angular momentum, a fundamental physical quantity, can be divided into spin angular momentum(SAM) and orbital angular momentum(OAM) in electromagnetic waves. Helically-phased or twisted light beams carrying OAM that exploit the spatial structure physical dimension of electromagnetic waves have benefited wide applications ranging from optical manipulation to quantum information processing. Using the two distinct properties of OAM, i.e., inherent orthogonality and unbounded states in principle, one can develop OAM modulation and OAM multiplexing techniques for twisted optical communications. OAM multiplexing is an alternative space-division multiplexing approach employing an orthogonal mode basis related to the spatial phase structure. In this paper, we review the recent progress in twisted optical communications using OAM in free space and fiber. The basic concept of momentum, angular momentum, SAM, OAM and OAM-carrying twisted optical communications,key techniques and devices of OAM generation/(de)multiplexing/detection, high-capacity spectrally-efficient free-space OAM links, fiber-based OAM links, and OAM processing functions are presented. Ultra-high spectral efficiency and petabit-scale freespace data links are achieved benefiting from OAM multiplexing. The key techniques and challenges of twisted optical communications are also discussed. Twisted optical communications using OAM are compatible with other existing physical dimensions such as frequency/wavelength, amplitude, phase, polarization and time, opening a possible way to facilitate continuous increase of the aggregate transmission capacity and spectral efficiency through N-dimensional multiplexing. 相似文献
4.
《中国光学快报(英文版)》2018,(11)
An all-fiber femtosecond vortex laser based on common fiber components is constructed. It can produce femtosecond orbital angular momentum modes whose time pulse width is 398 fs. The topological charge of output orbital angular momentum(OAM) modes from this laser can be adjusted among 0, +1, and-1 easily while it is also easy to convert between continuous OAM modes and pulse OAM modes. 相似文献
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射频涡旋电磁波等相位面呈涡旋状,是一种携有新自由度-轨道角动量的电磁波。在轨道角动量模式理论分析的基础上,提出了在中心频率6 GHz处产生携有轨道角动量的涡旋电磁波的一种圆微带天线阵新结构,设计了以双层圆形微带天线为阵元组成的圆形阵列天线,通过控制馈源的相位差,得到模式量子数为0,1,2, 3, 4的轨道角动量。仿真结果表明:携轨道角动量的电磁波矢量电场图具有涡旋波阵面的特性,合适的阵列半径和馈线排列分布将产生携有良好轨道角动量特性的涡旋电磁波,而不当的阵列半径或馈线排列分布将出现能量的分散或者相互耦合的问题。 相似文献
6.
射频涡旋电磁波等相位面呈涡旋状,是一种携有新自由度-轨道角动量的电磁波。在轨道角动量模式理论分析的基础上,提出了在中心频率6 GHz处产生携有轨道角动量的涡旋电磁波的一种圆微带天线阵新结构,设计了以双层圆形微带天线为阵元组成的圆形阵列天线,通过控制馈源的相位差,得到模式量子数为0,1,2, 3, 4的轨道角动量。仿真结果表明:携轨道角动量的电磁波矢量电场图具有涡旋波阵面的特性,合适的阵列半径和馈线排列分布将产生携有良好轨道角动量特性的涡旋电磁波,而不当的阵列半径或馈线排列分布将出现能量的分散或者相互耦合的问题。 相似文献
7.
The eigen-beams of orbital angular momentum (OAM) have helical wavefront and can be used to construct the channels for free space optical communication, i.e. orbital angular momentum multiplexing (OAMM). It is similar to time-division multiplexing (TDM) and wave-division multiplexing (WDM). We generate four helical beams with different OAM numbers by fork-like grating and modulates them mechanically. The modulated helical beams are then superposed coaxially into one single complex beam. In the receiver, the complex beam is separated into four helical beams with little mutual interference. The experimental results demonstrate the feasibility of OAMM by using the eigen-beams of orbital angular momentum. 相似文献
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Optical Review - Orbital angular momentum (OAM) beams have orthogonality between them, which can greatly increase the capacity of a communication system, but an OAM multiplexed communication system... 相似文献
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We analyze the orbital angular momentum (OAM) crosstalk of single photons propagation through low-order atmospheric turbulence. The probability models of the orbital angular momentum crosstalk for single photons propagation in the channel with the non-Kolmogorov turbulence tilt, coma, and astigmatism and defocus aberration have been established. It is found, for α = 11/3, that the turbulent tilt is the dominant aberration which causes the orbital angular momentum crosstalk, the coma is second and the astigmatism is third, but the defocus aberration has no impact on OAM. The results also indicate that the regularities of orbital angular momentum crosstalk caused by the tilt, the coma and the astigmatism are almost the same, respectively. The crosstalk probability of the orbital angular momentum increases as the azimuth mode index p of Laguerre-Gaussian (LG) beam increases, the turbulent strength Cn2 enhances, the orbital angular momentum quantum number rises, the diameter of circular sampling aperture D and the channel zenith angle θ increase. 相似文献
12.
《中国光学快报(英文版)》2019,(12)
In free-space or in optical fibers, orbital angular momentum(OAM) multiplexing for information transmission has been greatly developed. The light sources used were well coherent communication bands, and the fibers used were customized. Here, we use an 810 nm femtosecond laser to generate optical vortices carrying OAM and then feed them into two kinds of commercial step-index few-mode fibers to explore the transmission characteristics of OAM modes. We also propose a method without multiple-input multiple-output digital signal processing to identify the input OAMs. It is of great guiding significance for high-dimensional quantum information experiments via the OAMs as a degree of freedom, using the light generated by the spontaneous parametric down-conversion as the source and the commercial fibers for information transmission. 相似文献
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The entangled orbital angular momentum(OAM) three photons propagating in Kolmogorov weak turbulence are investigated. Here, the single phase screen model is used to study the entanglement evolution of OAM photons. The results indicate that the entangled OAM three-qubit state with higher OAM modes will be more robust against turbulence.Furthermore, it is found that the entangled OAM three-qubit state has a higher overall transmission for small OAM values. 相似文献
16.
A simple optical system for the self-homodyne detection of the orbital angular momentum (OAM) carried by optical beams is introduced. We propose two different schemes based on the use of optical hybrids, which could detect the OAM mode number, even when the input beam might be slightly distorted. A balanced receiver is used to perform a self-homodyne measure of the optical signal from two different locations at the beam wavefront. 相似文献
17.
Hao Chen Zhongliang Yu Jingjing Hao Zhaozhong Chen Ji Xu Jianping Ding Hui-Tian Wang 《Applied physics. B, Lasers and optics》2014,114(3):355-359
We show that the spin angular momentum (SAM) flux in a space-variant linearly polarized beam can be separated in the focal plane. Such a beam carries only orbital angular momentum (OAM) and develops a net SAM flux upon focusing. The radial splitting of the SAM flux density is mediated by the phase vortex (or OAM) and can be controlled by the topological charge of the phase vortex. Optical trapping experiments verify the separation of the SAM flux density. The proposed approach enriches the manipulation of the angular momentum of light fields and inspires more designs of focus engineering, which would benefit optical micromanipulation of microscopic particles. 相似文献
18.
An experimental system consisting of a Dove prism embedded Mach-Zehnder (M-Z) interferometer and two gratings was built to sort and detect orbital angular momentum (OAM) states of light beams. The helical beams with different OAM states were generated by propagating the fundamental-mode Gaussian beam through a spatial light modulator. The Dove prism embedded M-Z interferometer was used to sort helical beams with odd or even OAM number and two binary amplitude gratings were used to measure the OAM states. Sorting of coaxially-superposed coherent and incoherent helical beams with odd and even OAM states was realized in the experiment. 相似文献
19.
With Rytov approximation and Kolmogorov spectrum model of index-of-refraction fluctuation, we study the effects of turbulence aberration on the orbital angular momentum of single photons in atmospheric communication channel. A theoretical model of measurement probabilities of orbital angular momentum states for single photons propagation under the Zernike tilt corrected slant path turbulent atmosphere channel is established. Our research shows that tilt-corrected residual aberration not only damage the initial OAM, but also induce new OAM. With the increasing of D/ρ0, the number of the initial OAM photons will go down while the effective number of new OAM ascends. Meanwhile, the receiving probability of initial OAM photons declines, as the turbulence shifts from weak to strong. For Zernike tilt-corrected residual aberration, the receiving probability of initial OAM photons declines as the diameter of detector increases. The effect of Zernike tilt-corrected residual aberration on OAM of the photons is more larger than the effect of Zernike tilt turbulent aberration. 相似文献
20.
涡旋光束是一种携带有轨道角动量的光束,在光学扳手、光通信、旋转探测等领域具有重要的应用价值.由于轨道角动量态是涡旋光束的特征值,因此如何探测光束的轨道角动量态分布至关重要.国内外学者已经提出了多种探测涡旋光束的技术,如干涉法、衍射光栅法、多普勒分析法、超材料表面法等.这些技术中,衍射光栅测量法较为简单易行,应用较广.本综述主要介绍了几种当前利用衍射光栅测量涡旋光束轨道角动量态的主流方法,同时也介绍了如何利用衍射光栅来测量光束的轨道角动量谱. 相似文献