scholarly journals Photocurrent detection of the orbital angular momentum of light

Science ◽  
2020 ◽  
Vol 368 (6492) ◽  
pp. 763-767 ◽  
Author(s):  
Zhurun Ji ◽  
Wenjing Liu ◽  
Sergiy Krylyuk ◽  
Xiaopeng Fan ◽  
Zhifeng Zhang ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Communication Networks ◽  
Orbital Angular Momentum ◽  
Optical Communication ◽  
Topological Charge ◽  
Optical Intensity ◽  
Phase Gradient ◽  
On Chip ◽  
A Current

Applications that use the orbital angular momentum (OAM) of light show promise for increasing the bandwidth of optical communication networks. However, direct photocurrent detection of different OAM modes has not yet been demonstrated. Most studies of current responses to electromagnetic fields have focused on optical intensity–related effects, but phase information has been lost. In this study, we designed a photodetector based on tungsten ditelluride (WTe2) with carefully fabricated electrode geometries to facilitate direct characterization of the topological charge of OAM of light. This orbital photogalvanic effect, driven by the helical phase gradient, is distinguished by a current winding around the optical beam axis with a magnitude proportional to its quantized OAM mode number. Our study provides a route to develop on-chip detection of optical OAM modes, which can enable the development of next-generation photonic circuits.

On-chip discrimination of orbital angular momentum of light with plasmonic nanoslits

Nanoscale ◽  
2016 ◽  
Vol 8 (4) ◽  
pp. 2227-2233 ◽  
Author(s):  
Shengtao Mei ◽  
Kun Huang ◽  
Hong Liu ◽  
Fei Qin ◽  
Muhammad Q. Mehmood ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Optical Communication ◽  
Communication System ◽  
Degree Of Freedom ◽  
System Capacity ◽  
Optical Communication System ◽  
On Chip

The orbital angular momentum (OAM) of light can be taken as an independent and orthogonal degree of freedom for multiplexing in an optical communication system, potentially improving the system capacity to hundreds of Tbits per second.

scholarly journals Ultrafast control of fractional orbital angular momentum of microlaser emissions

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhifeng Zhang ◽  
Haoqi Zhao ◽  
Danilo Gomes Pires ◽  
Xingdu Qiao ◽  
Zihe Gao ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Optical Communication ◽  
High Speed ◽  
Quantum Information Processing ◽  
Time Window ◽  
Gain Medium ◽  
Control Pulse ◽  
Processing Technologies ◽  
On Chip

Abstract On-chip integrated laser sources of structured light carrying fractional orbital angular momentum (FOAM) are highly desirable for the forefront development of optical communication and quantum information–processing technologies. While integrated vortex beam generators have been previously demonstrated in different optical settings, ultrafast control and sweep of FOAM light with low-power control, suitable for high-speed optical communication and computing, remains challenging. Here we demonstrate fast control of the FOAM from a vortex semiconductor microlaser based on fast transient mixing of integer laser vorticities induced by a control pulse. A continuous FOAM sweep between charge 0 and charge +2 is demonstrated in a 100 ps time window, with the ultimate speed limit being established by the carrier recombination time in the gain medium. Our results provide a new route to generating vortex microlasers carrying FOAM that are switchable at GHz frequencies by an ultrafast control pulse.

scholarly journals Characterization of topological charge and orbital angular momentum of shaped optical vortices

2014 ◽  
Vol 22 (24) ◽  
pp. 30315 ◽  
Author(s):  
Anderson M. Amaral ◽  
Edilson L. Falcão-Filho ◽  
Cid B. de Araújo
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Topological Charge ◽  
Optical Vortices

scholarly journals Sound vortex diffraction via topological charge in phase gradient metagratings

2020 ◽  
Vol 6 (40) ◽  
pp. eaba9876
Author(s):  
Yangyang Fu ◽  
Chen Shen ◽  
Xiaohui Zhu ◽  
Junfei Li ◽  
Youwen Liu ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Numerical Simulations ◽  
Orbital Angular Momentum ◽  
Topological Charge ◽  
Asymmetric Transmission ◽  
Phase Gradient ◽  
Wave Fields ◽  
Limited Ability ◽  
Helmholtz Resonators ◽  
Powerful Mechanism

Wave fields with orbital angular momentum (OAM) have been widely investigated in metasurfaces. By engineering acoustic metasurfaces with phase gradient elements, phase twisting is commonly used to obtain acoustic OAM. However, it has limited ability to manipulate sound vortices, and a more powerful mechanism for sound vortex manipulation is strongly desired. Here, we propose the diffraction mechanism to manipulate sound vortices in a cylindrical waveguide with phase gradient metagratings (PGMs). A sound vortex diffraction law is theoretically revealed based on the generalized conservation principle of topological charge. This diffraction law can explain and predict the complicated diffraction phenomena of sound vortices, as confirmed by numerical simulations. To exemplify our findings, we designed and experimentally verified a PGM based on Helmholtz resonators that support asymmetric transmission of sound vortices. Our work provides previously unidentified opportunities for manipulating sound vortices, which can advance more versatile design for OAM-based devices.

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.

scholarly journals Integrated Photonic Orbital Angular Momentum Multiplexing and Demultiplexing on Chip

2014 ◽  
Author(s):  
Ryan P. Scott ◽  
Roberto Proietti ◽  
Binbin Guan ◽  
S. J. Yoo
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
On Chip
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