scholarly journals Anomalous Bessel vortex beam: modulating orbital angular momentum with propagation

Nanophotonics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 677-682 ◽  
Author(s):  
Yuanjie Yang ◽  
Xinlei Zhu ◽  
Jun Zeng ◽  
Xingyuan Lu ◽  
Chengliang Zhao ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Quantum Information ◽  
Orbital Angular Momentum ◽  
Topological Charge ◽  
Propagation Distance ◽  
Zero Order ◽  
Vortex Beam ◽  
Bessel Beams ◽  
Propagation Axis ◽  
Continuous Range

AbstractZero-order and higher-order Bessel beams are well-known nondiffracting beams. Namely, they propagate with invariant profile (intensity) and carry a fixed orbital angular momentum. Here, we propose and experimentally study an anomalous Bessel vortex beam. Unlike the traditional Bessel beams, the anomalous Bessel vortex beam carries decreasing orbital angular momentum along the propagation axis in free space. In other words, the local topological charge is inversely proportional to the propagation distance. Both the intensity and phase patterns of the generated beams are measured experimentally, and the experimental results agree well with the simulations. We demonstrate an easy way to modulate the beam’s topological charge to be an arbitrary value, both integer and fractional, within a continuous range. The simplicity of this geometry encourages its applications in optical trapping and quantum information, and the like.

Detecting the topological charge of a vortex beam by an arc slit diffraction

2017 ◽  
Vol 31 (23) ◽  
pp. 1750172 ◽  
Author(s):  
Dongzhi Fu ◽  
Hailong Zhou ◽  
Kaiwei Wang ◽  
Pei Zhang ◽  
Jianji Dong ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Diffraction Pattern ◽  
Orbital Angular Momentum ◽  
Topological Charge ◽  
Light Spot ◽  
Far Field ◽  
Vortex Beam ◽  
Efficient Measurement ◽  
Vortex Beams

The simple and efficient measurement of the light orbital angular momentum (OAM) is essential to both the classical and quantum applications with vortex beams. Here, we study the diffraction pattern in the far field when a vortex beam passes through an arc slit and demonstrate experimentally that a light spot of the diffraction pattern has a displacement which is linear to the topological charge (TC) of the incident vortex beam. Based on this property, this method is capable of measuring both modulus and sign of TC of the vortex beam. Furthermore, this scheme allows identifying multiple OAM states simultaneously.

scholarly journals Capacity of a Radio Vortex Communication System Using a Partial Angular Aperture Receiving Scheme under the Horizontal Non-Kolmogorov Model

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1778
Author(s):  
Qian Ma ◽  
Hengkai Zhao
Keyword(s):  
Angular Momentum ◽  
Atmospheric Turbulence ◽  
Orbital Angular Momentum ◽  
Communication System ◽  
Propagation Distance ◽  
Vortex Beam ◽  
Frequency Range ◽  
Long Distance ◽  
Angular Aperture ◽  
Transmission Frequency

A partial receiving scheme based on limited angular aperture multi-beam receiving and demultiplexing can solve the difficulty caused by the divergence of the vortex beam in the conventional whole beam receiving scheme and realize the long-distance transmission of the vortex wave. The propagation of the radio vortex beam in atmospheric turbulence is of significant importance in theoretical study and practical applications. In this paper, the influence of atmospheric turbulence on the performance of a radio vortex (RV) communication system based on a partial angular aperture receiving (PAAR) scheme under the horizontal non-Kolmogorov channel model is studied. The spiral spectrum of the PAAR scheme and the channel capacity of the RV communication system using the PAAR scheme are derived. Simulation results demonstrate that the selected transmission frequency range has a great influence on the RV communication system based on the PAAR scheme, and the choice of the orbital angular momentum (OAM) mode number L has an influence on the propagation distance. The capacity of RV communication systems based on the PAAR scheme increases with the increase of the transmission frequency in the selected transmission frequency range of 10 GHz–60 GHz. When the number of orbital angular momentum (OAM) modes L is small, we can improve the signal-to-noise ratio (SNR) to obtain a larger capacity of the RV communication system based on the PAAR scheme over a longer propagation distance.

On-chip orbital angular momentum detection via catenary grating metasurface

2021 ◽  
Author(s):  
Panpan Chen ◽  
Cong Chen ◽  
Jianxin Xi ◽  
Xiang Du ◽  
Li Liang ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Integrated Circuits ◽  
Orbital Angular Momentum ◽  
Topological Charge ◽  
Detection System ◽  
Great Promise ◽  
Vortex Beam ◽  
Detection Approach ◽  
On Chip ◽  
Plasmon Polaritons

Abstract Vortex lights with optical orbital angular momentum (OAM) have shown great promise in the areas of optical communication, optical manipulation and quantum optics. However, traditional methods for detecting the topological charge of vortex beams, such as interference and diffraction, are still challenging in miniaturization of the detection system and perfect matching of wave vectors. Here, a detection approach is proposed for measuring the topological charge of Laguerre-Gaussian (LG) vortex beam based on a catenary grating metasurface. According to the wave vector matching principle, the LG vortex beam can be coupled into surface plasmon polaritons (SPPs) waves propagating in different directions by using the well-designed catenary grating structure. The positive and negative of the topological charge can be distinguished by different arrangement of the catenary gratings. Besides, the propagation angle of the launched SPPs waves increases with the value of the topological charge. We believe that the proposed device would have a broader application prospect in high compact photonic integrated circuits.

scholarly journals High-Efficiency Spin-Related Vortex Metalenses

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1485
Author(s):  
Wei Wang ◽  
Ruikang Zhao ◽  
Shilong Chang ◽  
Jing Li ◽  
Yan Shi ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Topological Charge ◽  
High Efficiency ◽  
Infrared Band ◽  
Mid Infrared ◽  
Integrated Devices ◽  
Vortex Beams ◽  
Topological Charges

In this paper, one spin-selected vortex metalens composed of silicon nanobricks is designed and numerically investigated at the mid-infrared band, which can produce vortex beams with different topological charges and achieve different spin lights simultaneously. Another type of spin-independent vortex metalens is also designed, which can focus the vortex beams with the same topological charge at the same position for different spin lights, respectively. Both of the two vortex metalenses can achieve high-efficiency focusing for different spin lights. In addition, the spin-to-orbital angular momentum conversion through the vortex metalens is also discussed in detail. Our work facilitates the establishment of high-efficiency spin-related integrated devices, which is significant for the development of vortex optics and spin optics.

scholarly journals Sectorial perturbation of vortex beams: Shannon entropy, orbital angular momentum and topological charge

2019 ◽  
Vol 43 (5) ◽  
pp. 723-734 ◽  
Author(s):  
A.V. Volyar ◽  
M.V. Bretsko ◽  
Ya.E. Akimova ◽  
Yu.A. Egorov ◽  
V.V. Milyukov
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Shannon Entropy ◽  
Topological Charge ◽  
External Perturbation ◽  
Informational Entropy ◽  
Large Perturbation ◽  
Wide Range ◽  
Vortex Beams ◽  
Computing Measuring

Transformations of the vortex beams structure subjected to sectorial perturbation were theoretically and experimentally studied. The analysis was based on computing (measuring) the vortex spectrum that enables us to find the orbital angular momentum (OAM) and Shannon entropy (informational entropy). We have revealed that, in the general case, the number of vortices caused by an external perturbation is not related to the topological charge. For arbitrary perturbation, the topological charge remains equal to the initial topological charge of the unperturbed vortex beam. Growth of the vortex number induced by perturbations is associated with the optical uncertainty principle between the sectorial angle and the OAM. The computer simulation has shown that OAM does not depend on the number of vortices induced by perturbations. Moreover, two maxima are formed both in the positive and negative regions of the vortex spectrum. As a result, the OAM does not practically change in a wide range of perturbation angles from 0 to 90 °. However, at large perturbation angles, when the energy is almost equally redistributed between the vortex modes with opposite signs of the topological charge, the OAM rapidly decreases. At the same time, the Shannon entropy monotonically increases with growing perturbation angle. This is due to the fact that the entropy depends only on the number of vortex states caused by external perturbations.

Spin-Orbital Angular Momentum of Light and Its Application

2020 ◽  
Vol 29 (10) ◽  
pp. 28-31
Author(s):  
Teun-Teun KIM
Keyword(s):  
Angular Momentum ◽  
Quantum Entanglement ◽  
Orbital Angular Momentum ◽  
Phase Distribution ◽  
Optical Vortex ◽  
Spin Orbit ◽  
Vortex Beam ◽  
Spin Orbital ◽  
Matter Interaction ◽  
Light Matter Interaction

Like the eletron, the photon carries spin and orbital angular momentum caused by the polarization and the spatial phase distribution of light, respectively. Since the first observation of an optical vortex beam with orbital angular momentum (OAM), the use of an optical vortex beam has led to further studies on the light-matter interaction, the quantum nature of light, and a number of applications. In this article, using a metasurface with geometrical phase, we introduce the fundamental origins and some important applications of light with spin-orbit angular momentum as examples, including optical vortex tweezer and quantum entanglement of the spin-orbital angular momentum.

Determining the Orbital Angular Momentum of Vortex Beam by Young’s Double-Slit Interference Experiment

2008 ◽  
Vol 35 (7) ◽  
pp. 1063-1067 ◽  
Author(s):  
陈子阳 Chen Ziyang ◽  
张国文 Zhang Guowen ◽  
饶连周 Rao Lianzhou ◽  
蒲继雄 Pu Jixiong
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Vortex Beam ◽  
Interference Experiment ◽  
Double Slit
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