Review on fractional vortex beam

Abstract As an indispensable complement to an integer vortex beam, the fractional vortex beam has unique physical properties such as radially notched intensity distribution, complex phase structure consisting of alternating charge vortex chains, and more sophisticated orbital angular momentum modulation dimension. In recent years, we have noticed that the fractional vortex beam was widely used for complex micro-particle manipulation in optical tweezers, improving communication capacity, controllable edge enhancement of image and quantum entanglement. Moreover, this has stimulated extensive research interest, including the deep digging of the phenomenon and physics based on different advanced beam sources and has led to a new research boom in micro/nano-optical devices. Here, we review the recent advances leading to theoretical models, propagation, generation, measurement, and applications of fractional vortex beams and consider the possible directions and challenges in the future.

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Optical vortex lattice: an exploitation of orbital angular momentum

Nanophotonics ◽

10.1515/nanoph-2021-0139 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Liuhao Zhu ◽

Miaomiao Tang ◽

Hehe Li ◽

Yuping Tai ◽

Xinzhong Li

Keyword(s):

Angular Momentum ◽

Optical Tweezers ◽

Orbital Angular Momentum ◽

Vortex Lattice ◽

Optical Vortex ◽

Yeast Cells ◽

Particle Manipulation ◽

Complex Motion ◽

Potential Applications ◽

Vortex Beams

Abstract Generally, an optical vortex lattice (OVL) is generated via the superposition of two specific vortex beams. Thus far, OVL has been successfully employed to trap atoms via the dark cores. The topological charge (TC) on each optical vortex (OV) in the lattice is only ±1. Consequently, the orbital angular momentum (OAM) on the lattice is ignored. To expand the potential applications, it is necessary to rediscover and exploit OAM. Here we propose a novel high-order OVL (HO-OVL) that combines the phase multiplication and the arbitrary mode-controllable techniques. TC on each OV in the lattice is up to 51, which generates sufficient OAM to manipulate microparticles. Thereafter, the entire lattice can be modulated to desirable arbitrary modes. Finally, yeast cells are trapped and rotated by the proposed HO-OVL. To the best of our knowledge, this is the first realization of the complex motion of microparticles via OVL. Thus, this work successfully exploits OAM on OVL, thereby revealing potential applications in particle manipulation and optical tweezers.

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Arbitrary polarization conversion for pure vortex generation with a single metasurface

Nanophotonics ◽

10.1515/nanoph-2020-0332 ◽

2020 ◽

Vol 10 (1) ◽

pp. 727-732

Author(s):

Marco Piccardo ◽

Antonio Ambrosio

Keyword(s):

Angular Momentum ◽

Polarization Conversion ◽

Vortex Beam ◽

Vortex Generation ◽

Optical Elements ◽

Amplitude Control ◽

Cavity Resonators ◽

Vortex Beams ◽

Topological Charges ◽

Selection Of

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

Materials ◽

10.3390/ma11122448 ◽

2018 ◽

Vol 11 (12) ◽

pp. 2448 ◽

Cited By ~ 10

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.

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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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Strongly Focused Circularly Polarized Optical Vortices Regulated by a Fractal Conical Lens

Applied Sciences ◽

10.3390/app10010028 ◽

2019 ◽

Vol 10 (1) ◽

pp. 28

Author(s):

Zhirong Liu ◽

Kelin Huang ◽

Anlian Yang ◽

Xun Wang ◽

Philip H. Jones

Keyword(s):

Angular Momentum ◽

Optical Tweezers ◽

Numerical Aperture ◽

Optical Element ◽

Optical Vortex ◽

Optical Vortices ◽

Circularly Polarized ◽

Strong Focusing ◽

New Type ◽

Vortex Beams

In this paper, a recently-proposed pure-phase optical element, the fractal conical lens (FCL), is introduced for the regulation of strongly-focused circularly-polarized optical vortices in a high numerical aperture (NA) optical system. Strong focusing characteristics of circularly polarized optical vortices through a high NA system in cases with and without a FCL are investigated comparatively. Moreover, the conversion between spin angular momentum (SAM) and orbital angular momentum (OAM) of the focused optical vortex in the focal vicinity is also analyzed. Results revealed that a FCL of different stage S could significantly regulate the distributions of tight focusing intensity and angular momentum of the circularly polarized optical vortex. The interesting results obtained here may be advantageous when using a FCL to shape vortex beams or utilizing circularly polarized vortex beams to exploit new-type optical tweezers.

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Vortex Beam Encoded All-Optical Logic Gates Based on Nano-Ring Plasmonic Antennas

Nanomaterials ◽

10.3390/nano9121649 ◽

2019 ◽

Vol 9 (12) ◽

pp. 1649

Author(s):

Houquan Liu ◽

Hongchang Deng ◽

Shijie Deng ◽

Chuanxin Teng ◽

Ming Chen ◽

...

Keyword(s):

Logic Gate ◽

Logic Gates ◽

Vortex Beam ◽

Optical Logic ◽

Optical Elements ◽

Optical Logic Gates ◽

Input Signals ◽

All Optical ◽

Vortex Beams ◽

Polarization States

Vortex beam encoded all-optical logic gates are suggested to be very important in future information processing. However, within current logic devices, only a few are encoded by using vortex beams and, in these devices, some space optical elements with big footprints (mirror, dove prism and pentaprism) are indispensable components, which is not conducive to device integration. In this paper, an integrated vortex beam encoded all-optical logic gate based on a nano-ring plasmonic antenna is proposed. In our scheme, by defining the two circular polarization states of the input vortex beams as the input logic states and the normalized intensity of the plasmonic field at the center of the nano-ring as the output logic states, OR and AND (NOR and NAND) logic gates are realized when two 1st (1st) order vortex beams are chosen as the two input signals; and a NOT logic gate is obtained when one 1st order vortex beam is chosen as the input signal. In addition, by defining the two linear polarization states (x and y polarization) of the input vortex beams as the two input logic states, an XNOR logic gate is realized when two 1st order vortex beams are chosen as the two input signals.

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Optical Fibre Micro/Nano Tips as Fluorescence-Based Sensors and Interrogation Probes

Optics ◽

10.3390/opt1020017 ◽

2020 ◽

Vol 1 (2) ◽

pp. 213-242 ◽

Cited By ~ 1

Author(s):

Simone Berneschi ◽

Andrea Barucci ◽

Francesco Baldini ◽

Franco Cosi ◽

Franco Quercioli ◽

...

Keyword(s):

Optical Tweezers ◽

Optical Fibre ◽

Near Field ◽

Optical Devices ◽

Biochemical Sensors ◽

Whispering Gallery ◽

Biochemical Sensing ◽

Nano Structures ◽

Microscope Imaging ◽

Physical And Chemical

Optical fibre micro/nano tips (OFTs), defined here as tapered fibres with a waist diameter ranging from a few microns to tens of nanometres and different tip angles (i.e., from tens of degrees to fractions of degrees), represent extremely versatile tools that have attracted growing interest during these last decades in many areas of photonics. The field of applications can range from physical and chemical/biochemical sensing—also at the intracellular levels—to the development of near-field probes for microscope imaging (i.e., scanning near-field optical microscopy (SNOM)) and optical interrogation systems, up to optical devices for trapping and manipulating microparticles (i.e., optical tweezers). All these applications rely on the ability to fabricate OFTs, tailoring some of their features according to the requirements determined by the specific application. In this review, starting from a short overview of the main fabrication methods used for the realisation of these optical micro/nano structures, the focus will be concentrated on some of their intriguing applications such as the development of label-based chemical/biochemical sensors and the implementation of SNOM probes for interrogating optical devices, including whispering gallery mode microcavities.

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