Conversions of linear-circular polarizations and spin-orbital angular momentums in a focused vector vortex beam with fractional topological charges

AbstractThe purity of an optical vortex beam depends on the spread of its energy among different azimuthal and radial modes, also known as $\ell $- and p-modes. The smaller the spread, the higher the vortex purity and more efficient its creation and detection. There are several methods to generate vortex beams with well-defined orbital angular momentum, but only few exist allowing selection of a pure radial mode. These typically consist of many optical elements with rather complex arrangements, including active cavity resonators. Here, we show that it is possible to generate pure vortex beams using a single metasurface plate—called p-plate as it controls radial modes—in combination with a polarizer. We generalize an existing theory of independent phase and amplitude control with birefringent nanopillars considering arbitrary input polarization states. The high purity, sizeable creation efficiency, and impassable compactness make the presented approach a powerful complex amplitude modulation tool for pure vortex generation, even in the case of large topological charges.

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Multi-channeled vortex beam switch with moiré metasurfaces

Journal of Optics ◽

10.1088/2040-8986/ac38c4 ◽

2021 ◽

Author(s):

Cheng Cui ◽

Zheng Liu ◽

Bin Hu ◽

Yurong Jiang ◽

Juan Liu

Keyword(s):

Functional Diversity ◽

Optical Communications ◽

Topological Charge ◽

Signal Transmission ◽

Polarized Light ◽

Vortex Beam ◽

Practical Applications ◽

Linearly Polarized ◽

Vortex Beams ◽

Topological Charges

Abstract Tunable metasurface devices are considered to be an important link for metasurfaces to practical applications due to their functional diversity and high adaptability to the application scenarios. Metasurfaces have unique value in the generation of vortex beams because they can realize light wavefronts of any shape. In recent years, several vortex beam generators using metasurfaces have been proposed. However, the topological charge generally lacks tunability, which reduces the scope of their applications. Here, we propose an active tunable multi-channeled vortex beam switch based on a moiré structure composed of two cascaded dielectric metasurfaces. The simulation results show that when linearly polarized light with a wavelength of 810 nm is incident, the topological charge from -6 to +6 can be continuously generated by relatively rotating the two metasurfaces. Meanwhile, different topological charges are deflected to different spatial channels, realizing the function of multi-channeled signal transmission. We also study the efficiency and broadband performance of the structure. The proposed multi-channeled separation method of vortex beams that can actively tune topological charges paves the way for the compactness and functional diversity of devices in the fields of optical communications, biomedicine, and optoelectronics.

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Spin-Orbital Angular Momentum of Light and Its Application

Physics and High Technology ◽

10.3938/phit.29.037 ◽

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.

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Rapid generation of perfect vortex beam without side lobes

Modern Physics Letters B ◽

10.1142/s0217984918502895 ◽

2018 ◽

Vol 32 (24) ◽

pp. 1850289

Author(s):

Siqi Li ◽

Mulong Liu ◽

Xingyi Li ◽

Zhiqiang Ge ◽

Lingxuan Zhang

Keyword(s):

Angular Momentum ◽

Orbital Angular Momentum ◽

Optical Communication ◽

Spatial Light Modulators ◽

Vortex Beam ◽

Digital Micromirror Device ◽

Light Modulators ◽

Rapid Generation ◽

Rapid Switching ◽

Topological Charges

We have proposed an approach for rapid generation of perfect vortex beam without side lobes through a digital micromirror device (DMD). Employing this method, the amplitude and phase of far field can be controlled indirectly by changing the rotation state of each unit on the DMD. The perfect vortex beams of equal rings diameter independent of their topological charges are generated commendably and the side lobes are avoided. Moreover, we have demonstrated rapid switching among the generated orbital angular momentum modes at the speed of 10 kHz, which is much faster than that of the usual method realized by spatial light modulators (SLMs). The proposed method is very beneficial for the optical communication and trapping or manipulating the small particle based on orbital angular momentum modes.

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Measurement of Airy-vortex beam topological charges based on a pixelated micropolarizer array

Applied Optics ◽

10.1364/ao.55.009299 ◽

2016 ◽

Vol 55 (32) ◽

pp. 9299 ◽

Cited By ~ 6

Author(s):

Yuntian Zhang ◽

Qingchuan Zhang ◽

Xuan Ma ◽

Zhaoxiang Jiang ◽

Tan Xu ◽

...

Keyword(s):

Vortex Beam ◽

Topological Charges

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Spiral phase plate with multiple singularity centers

Computer Optics ◽

10.18287/2412-6179-co-774 ◽

2020 ◽

Vol 44 (6) ◽

pp. 901-908

Author(s):

V.V. Kotlyar ◽

A.A. Kovalev ◽

E.S. Kozlova ◽

A.P. Porfirev

Keyword(s):

Topological Charge ◽

Beam Power ◽

Phase Plate ◽

Circular Aperture ◽

Vortex Beam ◽

Finite Radius ◽

Phase Singularity ◽

Initial Plane ◽

Topological Charges ◽

Spiral Phase

We investigate a multispiral phase plate (MSPP) with multiple centers of phase singularity arbitrarily located in the MSPP plane. Equations to describe the topological charge of an optical vortex in the initial plane immediately behind the MSPP and orbital angular momentum (OAM) normalized relative to the beam power are derived. The topological charge in the initial plane is found as a sum of the topological charges of all singularities if their centers are located inside a finite-radius circular aperture. If the phase singularity centers are partially located on the boundary of a circular diaphragm limiting the MSPP, the total topological charge is found as the sum of all singularities divided by 2. Total OAM that the vortex carries depends on the location of the singularity centers: the farther from the center of the plate the singularity center is located, the smaller is its contribution to the OAM. If all singularity centers are located on the boundary of the diaphragm limiting MSPP, then the OAM of the vortex beam equals zero, although in this case the topological charge of the beam is nonzero.

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Holographic-Inspired Multiple Circularly Polarized Vortex-Beam Generation with Flexible Topological Charges and Beam Directions

Physical Review Applied ◽

10.1103/physrevapplied.11.054027 ◽

2019 ◽

Vol 11 (5) ◽

Cited By ~ 6

Author(s):

Majid Karimipour ◽

Nader Komjani ◽

Iman Aryanian

Keyword(s):

Vortex Beam ◽

Circularly Polarized ◽

Beam Generation ◽

Topological Charges

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Experimental investigation on optical vortex tweezers for microbubble trapping

Open Physics ◽

10.1515/phys-2018-0052 ◽

2018 ◽

Vol 16 (1) ◽

pp. 383-386 ◽

Cited By ~ 2

Author(s):

Xiaoming Zhou ◽

Ziyang Chen ◽

Zetian Liu ◽

Jixiong Pu

Keyword(s):

Optical Tweezers ◽

Laser Power ◽

Topological Charge ◽

Force Measurement ◽

Numerical Aperture ◽

Optical Vortex ◽

Gradient Force ◽

Vortex Beam ◽

Trapping Forces ◽

Topological Charges

AbstractIn this paper, we investigated the microbubble trapping using optical vortex tweezers. It is shown that the microbubble can be trapped by the vortex optical tweezers, in which the trapping light beam is of vortex beam. We studied a relationship between the transverse capture gradient force and the topological charges of the illuminating vortex beam. For objective lenses with numerical aperture of 1.25 (100×), the force measurement was performed by the power spectral density (PSD) roll-off method. It was shown that transverse trapping forces of vortex optical tweezers increase with the increment of the laser power for fixed topological charge. Whereas, the increase in the topological charges of vortex beam for the same laser power results in the decrease of the transverse trapping forces. The experimental results demonstrated that the laser mode (topological charge) has significant influence on the lateral trapping force.

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