FOCUS SHAPING OF CYLINDRICALLY POLARIZED VORTEX BEAMS BY A LINEAR AXICON

Focus shaping of cylindrically polarized vortex beams (CPVBs) by linear axicon is studied theoretically. Vector diffraction theory has been used to derive the expressions of the light field in the focal region. It is shown that a different intensity distribution in the focal region can be obtained by adjusting the topological charge, the polarization rotation angle and the numerical aperture maximal angle. A focal spot, a dark channel and a flat-topped shapes are formed by choosing proper values of parameters. A controllable polarization state of dark channel is obtained. The different focal region shapes may find wide applications such as material processing and optical tweezers.

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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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Focus shaping of cylindrically polarized vortex beams by a high numerical-aperture lens

Optics & Laser Technology ◽

10.1016/j.optlastec.2008.06.012 ◽

2009 ◽

Vol 41 (3) ◽

pp. 241-246 ◽

Cited By ~ 55

Author(s):

Lianzhou Rao ◽

Jixiong Pu ◽

Zhiyang Chen ◽

Pu Yei

Keyword(s):

Numerical Aperture ◽

High Numerical Aperture ◽

Focus Shaping ◽

Vortex Beams

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Characterization of ultrashort pulses in the focal region of refractive systems

Acta Universitaria ◽

10.15174/au.2013.552 ◽

2013 ◽

Vol 23 ◽

pp. 3-6

Author(s):

L. García-Martínez ◽

M. Rosete-Aguilar ◽

J. Garduño-Mejía

Keyword(s):

Group Velocity Dispersion ◽

Numerical Aperture ◽

Ultrashort Pulses ◽

Diffraction Theory ◽

Wave Number ◽

Focal Region ◽

Propagation Time ◽

Pulse Shaper ◽

Third Order ◽

Diffraction Integral

In this work we analyze the spatio-temporal intensity of sub-20 fs pulses with a carrier wavelength of 810 nm along the optical axis of low numerical aperture achromatic and apochromatic doublets designed in the IR region by using the scalar diffraction theory. The diffraction integral is solved by expanding the wave number around the carrier frequency of the pulse in a Taylor series up to third order, and then the integral over the frequencies is solved by using the Gauss-Legendre quadrature method. We will show that the third-order group velocity dispersion (GVD) is not negligible for 10 fs pulses at 810 nm propagating through the low numerical aperture doublets, and its effect is more important than the propagation time difference (PTD). For sub-20 fs pulses, these two effects make the use of a pulse shaper necessary to correct for second and higher-order GVD terms and also the use of apochromatic optics to correct the PTD effect.

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A mode generator and multiplexer at visible wavelength based on all-fiber mode selective coupler

Nanophotonics ◽

10.1515/nanoph-2020-0050 ◽

2020 ◽

Vol 9 (4) ◽

pp. 973-981 ◽

Cited By ~ 1

Author(s):

Han Yao ◽

Fan Shi ◽

Zhaoyang Wu ◽

Xinzhu Xu ◽

Teng Wang ◽

...

Keyword(s):

Phase Shift ◽

Intensity Distribution ◽

Linear Polarization ◽

Mode Conversion ◽

Polarization State ◽

Stimulated Emission ◽

Wavelength Multiplexing ◽

Mode Converters ◽

Fiber Mode ◽

Vortex Beams

AbstractUsing an all-fiber mode selective coupler (MSC) at the visible band, here we experimentally demonstrate a generating and wavelength multiplexing scheme for the cylindrical vector (CV) and vortex beams (VBs). The proposed MSCs act as efficient mode converters to produce spectrally insensitive high-order modes (HOMs) at the wavelength ranging from 450 to 980 nm, which have broad operation bandwidth (more than 7 nm), high mode conversion efficiency (94%), and purity (98%), and low insert loss (below 0.5 dB). By adjusting the polarization state and the phase shift of linear polarization (LP)11 mode respectively, the donut-shaped CVs and circular-polarization VBs are achieved. The focused intensity distribution of the donut beam on the cross- and axial-sections is monitored by using a confocal system. The all-fiber solution of producing and multiplexing HOMs opens a new route for stimulated emission depletion microscopy applications.

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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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