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

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.

scholarly journals Optical vortex lattice: an exploitation of orbital angular momentum

Nanophotonics ◽  
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.

Optical vortices in fiber

Nanophotonics ◽  
2013 ◽  
Vol 2 (5-6) ◽  
pp. 455-474 ◽  
Author(s):  
Siddharth Ramachandran ◽  
Poul Kristensen
Keyword(s):  
Angular Momentum ◽  
Optical Fibers ◽  
Orbital Angular Momentum ◽  
Optical Vortex ◽  
Optical Vortices ◽  
New Class ◽  
Phase Singularities ◽  
Vortex Beams ◽  
Exotic Beams

AbstractOptical vortex beams, possessing spatial polarization or phase singularities, have intriguing properties such as the ability to yield super-resolved spots under focussing, and the ability to carry orbital angular momentum that can impart torque to objects. In this review, we discuss the means by which optical fibers, hitherto considered unsuitable for stably supporting optical vortices, may be used to generate and propagate such exotic beams. We discuss the multitude of applications in which a new class of fibers that stably supports vortices may be used, and review recent experiments and demonstration conducted with such fibers.

Angular momentum transfer in vortex and non-vortex beams using optical tweezers

2003 ◽  
Author(s):  
Halina Rubinsztein-Dunlop ◽  
Alexis Bishop ◽  
Timo Nieminen ◽  
Simon Parkin ◽  
Norman Heckenberg
Keyword(s):  
Angular Momentum ◽  
Momentum Transfer ◽  
Optical Tweezers ◽  
Angular Momentum Transfer ◽  
Vortex Beams

scholarly journals Optical Vortices Generation by Azopolymeric Relief Gratings

2021 ◽  
Vol 24 (2) ◽  
pp. 104-111
Author(s):  
E. A. Melnikova ◽  
D. V. Gorbach ◽  
I. I. Rushnova ◽  
O. S. Kabanova ◽  
S. S. Slusarenko ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Optical Element ◽  
Holographic Recording ◽  
Optical Vortices ◽  
Stability Range ◽  
Force Microscopy ◽  
Azo Polymer ◽  
Phase Singularities ◽  
The Stability ◽  
Light Beams

The energy and spectral conditions for single-stage holographic recording of a diffraction optical element based on the carbazole-containing azo polymer, that forms singular light beams (optical vortices), have been established. With the atomic-force microscopy (AFM), the surface morphology of the recorded relief holograms was studying, and their diffraction efficiency has been estimated. The topology of the generated optical phase singularities has been studied and the stability range of an optical vortex having the topological charge l = 2 has been found. The possibility of using the developed diffractive optical element in the scheme of optical tweezers for manipulating micro-objects is demonstrated.

scholarly journals Birth of optical vortices in propagating fields with an original fractional topological charge

2020 ◽  
Vol 44 (4) ◽  
pp. 493-500
Author(s):  
A.A. Kovalev ◽  
A.P. Porfirev
Keyword(s):  
Angular Momentum ◽  
Free Space ◽  
Topological Charge ◽  
Random Phase ◽  
Phase Variation ◽  
Optical Vortex ◽  
Optical Vortices ◽  
Integer Number ◽  
Weak Phase ◽  
Phase Distortions

In contrast to the orbital angular momentum (OAM), which is conserved on free space propagation, the topological charge (TC) of a paraxial optical vortex (OV) is not conserved in the general case. Here, we investigate a Gaussian beam with a fractional TC in the original plane and demonstrate both theoretically and numerically how the TC changes in the course of propagation. Depending on the proximity of the topological charge to an even or odd integer number, an optical vortex with the original fractional TC is shown to behave in a number of different ways. For simple OVs (Laguerre-Gaussian or Bessel-Gaussian modes), TC is conserved both in propagation and after weak phase distortions. An experiment shows that when scattered by a random phase screen, the integer TC of an OV is conserved right up to a random phase variation of π. Therefore, in the case of weak turbulences, it is expedient to measure a discretely varying TC instead of a continuously varying OAM.

scholarly journals Angular Momentum-Dependent Transmission of Circularly Polarized Vortex Beams Through a Plasmonic Coaxial Nanoring

2018 ◽  
Vol 10 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Shuai Wang ◽  
Xiangping Li ◽  
Zi-Lan Deng ◽  
Yaoyu Cao ◽  
Dejiao Hu ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Circularly Polarized ◽  
Vortex Beams

scholarly journals Tuning the orbital angular momentum in optical vortex beams

2006 ◽  
Vol 14 (15) ◽  
pp. 6604 ◽  
Author(s):  
Christian H. J. Schmitz ◽  
Kai Uhrig ◽  
Joachim P. Spatz ◽  
Jennifer E. Curtis
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Optical Vortex ◽  
Vortex Beams

scholarly journals Experimental demonstration of cylindrical vector spatiotemporal optical vortex

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jian Chen ◽  
Chenhao Wan ◽  
Andy Chong ◽  
Qiwen Zhan
Keyword(s):  
Angular Momentum ◽  
Optical Tweezers ◽  
Orbital Angular Momentum ◽  
Optical Vortex ◽  
Spin Orbit ◽  
Experimental Demonstration ◽  
Matter Interaction ◽  
Light Matter Interaction ◽  
Angular Momentum Coupling ◽  
Momentum Coupling

Abstract We experimentally generate cylindrically polarized wavepackets with transverse orbital angular momentum, demonstrating the coexistence of spatiotemporal optical vortex with spatial polarization singularity. The results in this paper extend the study of spatiotemporal wavepackets to a broader scope, paving the way for its applications in various areas such as light–matter interaction, optical tweezers, spatiotemporal spin–orbit angular momentum coupling, etc.

scholarly journals Measurement of the orbital angular momentum of an astigmatic Hermite–Gaussian beam

2019 ◽  
Vol 43 (3) ◽  
pp. 356-367
Author(s):  
V.V. Kotlyar ◽  
A.A. Kovalev ◽  
A.P. Porfirev
Keyword(s):  
Angular Momentum ◽  
Gaussian Beam ◽  
Orbital Angular Momentum ◽  
Topological Charge ◽  
Optical Axis ◽  
Optical Vortex ◽  
Cylindrical Lens ◽  
Optical Vortices ◽  
Special Choice ◽  
Different Types

Here we study three different types of astigmatic Gaussian beams, whose complex amplitude in the Fresnel diffraction zone is described by the complex argument Hermite polynomial of the order (n, 0). The first type is a circularly symmetric Gaussian optical vortex with and a topological charge n after passing through a cylindrical lens. On propagation, the optical vortex "splits" into n first-order optical vortices. Its orbital angular momentum per photon is equal to n. The second type is an elliptical Gaussian optical vortex with a topological charge n after passing through a cylindrical lens. With a special choice of the ellipticity degree (1: 3), such a beam retains its structure upon propagation and the degenerate intensity null on the optical axis does not “split” into n optical vortices. Such a beam has fractional orbital angular momentum not equal to n. The third type is the astigmatic Hermite-Gaussian beam (HG) of order (n, 0), which is generated when a HG beam passes through a cylindrical lens. The cylindrical lens brings the orbital angular momentum into the original HG beam. The orbital angular momentum of such a beam is the sum of the vortex and astigmatic components, and can reach large values (tens and hundreds of thousands per photon). Under certain conditions, the zero intensity lines of the HG beam "merge" into an n-fold degenerate intensity null on the optical axis, and the orbital angular momentum of such a beam is equal to n. Using intensity distributions of the astigmatic HG beam in foci of two cylindrical lenses, we calculate the normalized orbital angular momentum which differs only by 7 % from its theoretical orbital angular momentum value (experimental orbital angular momentum is –13,62, theoretical OAM is –14.76).

Focusing of linearly-, and circularly polarized Gaussian background vortex beams by a high numerical aperture system afflicted with third-order astigmatism

2008 ◽  
Vol 281 (24) ◽  
pp. 5939-5948 ◽  
Author(s):  
Rakesh Kumar Singh ◽  
P. Senthilkumaran ◽  
Kehar Singh
Keyword(s):  
Numerical Aperture ◽  
Third Order ◽  
Circularly Polarized ◽  
High Numerical Aperture ◽  
Vortex Beams
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