Measurement of real phase distribution of a vortex beam propagating in free space based on an improved heterodyne interferometer

2021 ◽  
Vol 119 (2) ◽  
pp. 023504
Author(s):  
Jinmiao Guo ◽  
Shijie Zheng ◽  
Kainan Zhou ◽  
Guoying Feng
Keyword(s):  
Free Space ◽  
Phase Distribution ◽  
Vortex Beam ◽  
Heterodyne Interferometer

Free Space Realization of the Symmetrical Tunable Auto‐Focusing Lommel Gaussian Vortex Beam

2021 ◽  
pp. 2100419
Author(s):  
Jialong Tu ◽  
Xinyue Wang ◽  
Xing Yu ◽  
Haonan Wang ◽  
Dongmei Deng
Keyword(s):  
Free Space ◽  
Vortex Beam ◽  
Space Realization ◽  
Auto Focusing

scholarly journals Transparent Metasurface for Generating Microwave Vortex Beams with Cross-Polarization Conversion

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2448 ◽  
Author(s):  
Hongyu Shi ◽  
Luyi Wang ◽  
Mengran Zhao ◽  
Juan Chen ◽  
Anxue Zhang ◽  
...  
Keyword(s):  
Transmission Loss ◽  
Phase Distribution ◽  
Polarization Conversion ◽  
Vortex Beam ◽  
Cross Polarization ◽  
Measurement Results ◽  
Vortex Beams ◽  
Simulation Results ◽  
Polarization Level ◽  
Transmission Phase

In this paper, metasurfaces with both cross-polarization conversion and vortex beam-generating are proposed. The proposed finite metasurface designs are able to change the polarization of incident electromagnetic (EM) waves to its cross-polarization. In addition, they also can modulate the incidences into beams carrying orbital angular momentum (OAM) with different orders ( l = + 1 , l = + 2 , l = − 1 and l = − 2 ) by applying corresponding transmission phase distribution schemes on the metasurface aperture. The generated vortex beams are at 5.14 GHz. The transmission loss is lower than 0.5 dB while the co-polarization level is −10 dB compared to the cross-polarization level. The measurement results confirmed the simulation results and verified the properties of the proposed designs.

Nonparaxial properties of partially coherent Lorentz-Gauss vortex beam propagating in free space

Optik ◽  
2018 ◽  
Vol 165 ◽  
pp. 148-158 ◽  
Author(s):  
Yan Yin ◽  
Dajun Liu ◽  
Yaochuan Wang
Keyword(s):  
Free Space ◽  
Vortex Beam ◽  
Partially Coherent

Free-space information transfer using the elliptic vortex beam with fractional topological charge

2019 ◽  
Vol 431 ◽  
pp. 238-244 ◽  
Author(s):  
Xiaohui Zhang ◽  
Tian Xia ◽  
Shubo Cheng ◽  
Shaohua Tao
Keyword(s):  
Free Space ◽  
Topological Charge ◽  
Information Transfer ◽  
Vortex Beam

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.

scholarly journals Characterization of the Vortex Beam by Fermat’s Spiral

Photonics ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 102
Author(s):  
Ewa Frączek ◽  
Agnieszka Popiołek-Masajada ◽  
Sławomir Szczepaniak
Keyword(s):  
Phase Distribution ◽  
Phase Plate ◽  
Vortex Beam ◽  
Scanning Microscope ◽  
Object Beam ◽  
Fitting Method ◽  
Numerical Fitting ◽  
Helical Beam ◽  
Spiral Phase

In this paper, we characterize the helical beam structure through an analysis of the spiral character of the phase distribution inside a light beam. In particular, we show that a line connected with the 2π phase jump in the Laguerre–Gauss beam can be described by a Fermat’s spiral. We propose a numerical fitting method to determine the parameters of a spiral equation for the phase distribution of the helical beam. Next, we extend the procedure to a vortex beam created by the spiral phase plate and apply it to experimental phase maps, which allows us to recover the phase shift introduced into the object beam in the optical vortex scanning microscope.

scholarly journals Acoustic Bessel Vortex Beam by Quasi-Three-Dimensional Reflected Metasurfaces

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1388
Author(s):  
Yin Wang ◽  
Jiao Qian ◽  
Jian-Ping Xia ◽  
Yong Ge ◽  
Shou-Qi Yuan ◽  
...  
Keyword(s):  
Free Space ◽  
High Performance ◽  
Three Dimensional ◽  
Propagation Distance ◽  
Vortex Beam ◽  
Remote Communication ◽  
Long Distance ◽  
Broad Bandwidth ◽  
Vortex Beams ◽  
Distance Propagation

Vortex beams have a typical characteristic of orbital angular momentum, which provides a new degree of freedom for information processing in remote communication and a form of non-contact manipulation for trapping particles. In acoustics, vortex beams are generally observed on the surface of a metamaterial structure or in a waveguide with a hard boundary owing to the characteristic of easy diffusion in free space. The realization of an acoustic vortex beam with a long-distance propagation in free space still remains a challenge. To overcome this, we report a type of acoustic Bessel vortex (ABV) beam created by a quasi-three-dimensional reflected metasurface in free space based on phase modulation. By using the Bessel and vortex phase profiles, we can realize an ABV beam with the high performances of both Bessel and vortex beams, and its effective propagation distance is larger than 9.2λ in free space. Beyond that, we discuss the bandwidth and topological charge of the ABV beam in detail, and the fractional bandwidth can reach about 0.28. The proposed ABV beam has the advantages of a high-performance vortex, long-distance propagation, and broad bandwidth, which provide a new pathway for designing multifunctional vortex devices with promising applications.

Spatial phase retrieval of vortex beam using convolutional neural network

2021 ◽  
Author(s):  
Ge Ding ◽  
Wenjie Xiong ◽  
Peipei Wang ◽  
Zebin Huang ◽  
Yanliang He ◽  
...  
Keyword(s):  
Neural Network ◽  
Convolutional Neural Network ◽  
Phase Retrieval ◽  
Phase Distribution ◽  
Spherical Wave ◽  
Vortex Beam ◽  
Phase Front ◽  
Free Space Optical ◽  
Practical Applications ◽  
Spatial Phase

Abstract Vortex beam (VB) possessing spatially helical phase–front has attracted widespread attention in free-space optical communication, etc. However, the spiral phase of VB is susceptible to atmospheric turbulence, and effective retrieval of the distorted conjugate phase is crucial for its practical applications. Herein, a convolutional neural network (CNN) approach to retrieve the phase distribution of VB is experimentally demonstrated. We adopt a spherical wave to interfere with VB for converting its phase information into intensity changes, and construct a CNN model with excellent image processing capabilities to directly extract phase–front features from the interferogram. Since the interference intensity is correlated with the phase–front, the CNN model can effectively reconstruct the wavefront of conjugate VB carrying different initial phases from a single interferogram. The results show that the CNN-based phase retrieval method has a loss of 0.1418 in the simulation and a loss of 0.2344 for the experimental data, and remains robust even in turbulence environments. This approach can improve the information acquisition capability for recovering the distorted wavefront and reducing the reliance on traditional inverse retrieval algorithms, which may provide a promising tool to retrieve the spatial phase distributions of VBs.

Sign in / Sign up

Export Citation Format

Share Document