Rotating of low-refractive-index microparticles with a quasi-perfect optical vortex

Author(s):

Yansheng Liang and Ming Lei and Shaohui Yan and Manman Li and Yanan Cai and Zhaojun Wang and Xianghua Yu and Baoli Yao

Abstract:

“Low-refractive-index microparticles, such as hollow microspheres, have shown great significance in some applications, such as biomedical sensing and targeted drug delivery. However, optical trapping and manipulation of low-refractive-index microparticles are challenging, owing to the repelling force exerted by typical optical traps. In this paper, we demonstrated optical trapping and rotating of large-sized low-refractive-index microparticles by using quasi-perfect optical vortex (quasi-POV) beams, which were generated by Fourier transform of high-order quasi-Bessel beams. Numerical simulation was carried out to characterize the focusing property of the quasi-POV beams. The dynamics of low-refractive-index microparticles in the quasi-POV with various topological charges was investigated in detail. To improve the trapping and rotating performances of the vortex, a point trap was introduced at the center of the ring. Experimental results showed that the quasi-POV was preferable for manipulation of large-sized low-refractive-index microparticles, with its control of the particles’ rotating velocity dependent only on the topological charge due to the unchanged orbital radius.”

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Publication: Applied Optics
Issue/Year/DOI: Applied Optics Volume 57, Issue 1 pp. 79-84
DOI: 10.1364/ao.57.000079

Tunable third harmonic generation of vortex beams in an optical superlattice

Author(s):

Yu Wu and Rui Ni and Zhou Xu and Yaodong Wu and Xinyuan Fang and Dan Wei and Xiaopeng Hu and Yong Zhang and Min Xiao and Shining Zhu

Abstract:

“We report generation of tunable vortex beams in the blue spectral range, with a 3.3 nm spectral tuning range, by frequency tripling of the near-infrared (IR) wave at around 1.34 um in a LiTaO3 optical superlattice. The nonlinear crystal used in this work has a chirped dual-periodical structure which can provide two expanded reciprocal vectors for tunable performance of the cascaded third harmonic generation (THG). The maximum THG efficiency reaches about 1.4%.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express, Vol. 25, Issue 25, pp. 30820- 30826 (2017)
DOI: 10.1364/OE.25.030820

Propagation dynamics of partially coherent crescent-like optical beams in free space and turbulent atmosphere

Author(s):

F. Wang and J. Li and G. Martinez-Piedra and O. Korotkova
Abstract:

“We introduce theoretically and realize experimentally a class of random, wide-sense stationary optical beams with uniform correlations which, on propagation in free space, produce a crescent-like intensity distribution with the maximum at an off-axis position. The crescent’s position of maximum intensity accelerates transversally at intermediate distances, and then exhibits a constant lateral shift further from the axis in the far zone of the source. We also show that on propagation in the isotropic turbulent atmosphere, the crescent beam shifts away from the axis as well, but slower than in free space, with rate depending on the strength of turbulence. These results are of importance for optical systems operating through long-range turbulent channels in which a beam must have a range-dependent tilt, e.g. on travelling around an obstacle.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express Volume 25, Issue 21
DOI: 10.1364/OE.25.026055

Shaping of optical vector beams in three dimensions

Author(s):

Chenliang Chang and Yuan Gao and Jianpei Xia and Shouping Nie and Jianping Ding

Abstract:

“We present a method of shaping three-dimensional (3D) vector beams with prescribed intensity distribution and controllable polarization state variation along arbitrary curves in three dimensions. By employing a non-iterative 3D beam-shaping method developed for the scalar field,
we use two curved laser beams with mutually orthogonal polarization serving as base vector components with a high-intensity gradient and controllable phase variation,
so that they are collinearly superposed to produce a 3D vector beam. We experimentally demonstrate the generation of 3D vector beams that have a polarization gradient (spatially continuous variant polarization state) along 3D curves, which may find applications in polarizationmediated
processes, such as to drive the motion of micro-particles.”

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Publication: Optics Letters

Issue/Year/DOI: Optics Letters Volume 42, Issue 19 pp. 3884-3887 (2017)
DOI: 10.1364/OL.42.003884

Dynamic three-dimensional multifocal spots in high numerical-aperture objectives

Author(s):

Linwei Zhu and Rui Yang and Dawei Zhang and Junjie Yu and Jiannong Chen

Abstract:

“Multifocal spots in high numerical-aperture (NA) objectives has emerged as a rapid, parallel, and multi-location method in a multitude of applications. However, the typical method used for forming three-dimensional (3D) multifocal spots based on iterative algorithms limits the potential applications. We demonstrate a non-iterative method using annular subzone phases (ASPs) that are composed of many annular subareas in which phase-only distributions with different 3D displacements are filled. The dynamic 3D multifocal spots with controllable position of each focal spot in the focal volume of the objective are created using the ASPs. The experimental results of such dynamic tunable 3D multifocal spots offer the possibility of versatile process in laser 3D fabrication, optical trapping, and fast focusing scanned microscopic imaging.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express, Vol. 25, Issue 20, pp. 24756- 24766 (2018)
DOI: 10.1364/OE.25.024756

Real and virtual propagation dynamics of angular accelerating white light beams

Author(s):

Christian Vetter and Angela Dudley and Alexander Szameit and Andrew Forbes

Abstract:

“Accelerating waves have received significant attention of late, first in the optical domain and later in the form of electron matter waves, and have found numerous applications in non-linear optics, material processing, microscopy, particle manipulation and laser plasma interactions. Here we create angular accelerating light beams with a potentially unlimited acceleration rate. By employing wavelength independent digital holograms for the creation and propagation of white light beams, we are able to study the resulting propagation in real and virtual space. We find that dephasing occurs for real propagation and that this can be compensated for in a virtual propagation scheme when single plane dynamics are important. Our work offers new insights into the propagation dynamics of such beams and provides a versatile tool for further investigations into propagating structured light fields.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express Vol. 25, Issue 17, pp. 20530-20540 (2017)

DOI: 10.1364/OE.25.020530

 

Non-diffractive Bessel-Gauss beams for the detection of rotating object free of obstructions

Author(s):

Shiyao Fu and Tonglu Wang and Zheyuan Zhang and Yanwang Zhai and Chunqing Gao

Abstract:

“Bessel-Gauss beams carrying orbital angular momentum are widely known for their non-diffractive or self-reconstructing performance, and have been applied in lots of domains. Here we demonstrate that, by illuminating a rotating object with high-order Bessel-Gauss beams, a frequency shift proportional to the rotating speed and the topological charge is observed. Moreover, the frequency shift is still present once an obstacle exists in the path, in spite of the decreasing of received signals. Our work indicates the feasibility of detecting rotating objects free of obstructions, and has potential as obstruction-immune rotation sensors in engine monitoring, aerological sounding, and so on.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express , Vol. 25, Issue 17, pp. 20098- 20108 (2018)
DOI: 10.1364/OE.25.020098

Non-diffractive Bessel-Gauss beams for the detection of rotating object free of obstructions

Author(s):

Shiyao Fu and Tonglu Wang and Zheyuan Zhang and Yanwang Zhai and Chunqing Gao

Abstract:

“Bessel-Gauss beams carrying orbital angular momentum are widely known for
their non-diffractive or self-reconstructing performance, and have been applied in lots of
domains. Here we demonstrate that, by illuminating a rotating object with high-order Bessel-
Gauss beams, a frequency shift proportional to the rotating speed and the topological charge
is observed. Moreover, the frequency shift is still present once an obstacle exists in the path,
in spite of the decreasing of received signals. Our work indicates the feasibility of detecting
rotating objects free of obstructions, and has potential as obstruction-immune rotation sensors
in engine monitoring, aerological sounding, and so on.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express Volume 25, Issue 17 pp. 20098-20108 (2017)
DOI: 10.1364/oe.25.020098

Axial sub-Fourier focusing of an optical beam

Author(s):

Thomas Zacharias and Barak Hadad and Alon Bahabad and Yaniv Eliezer

Abstract:

“We demonstrate experimentally the generation of an optical beam having an axial focusing that is narrower than the Fourier limit. The beam is constructed from a superposition of Bessel beams with different longitudinal wave vectors, realizing a super-oscillatory axial intensity distribution. Such beams can be useful for microscopy and for optical particle manipulation.”

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Publication: Optics Letters

Issue/Year/DOI: Optics Letters Vol. 42, Issue 16, pp. 3205-3208 (2017)

DOI: 10.1364/OL.42.003205

 

Experimental study on the propagation characteristics of ring Airy Gaussian vortex beams

Author(s):

Musheng Chen and Sujuan Huang and Wei Shao and Xianpeng Liu

Abstract:

“The auto-focusing and auto-healing profiles
of linearly polarized ring Airy Gaussian vortex (RAiGV)
beams in linear media are investigated experimentally
based on spatial light modulators and computer-generated
holograms. It is found that the parameters of incident beams
greatly affect the auto-focusing profiles of RAiGV. The focal
length increases as the radius of the primary ring, scaling
factor and waist radius increases, and the focal length
decreases slightly as topological charges increase. The peak
intensity at focal point increases with the increasing topological
charges and waist radius, or with the decreasing
scaling factor and the radius of the primary ring. The phase
singularity of the RAiGV beams remains unchanged during
propagation. The RAiGV beams also exhibit remarkable
resilience against perturbations and tend to reconstruct its
intensity sharp. Meanwhile, the abruptly auto-focusing property
can be controlled by blocking few inner or outer rings
of the RAiGV beams. These studies provide useful insight
in the study of Airy vortex beam and its further applications”

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Publication: Applied Physics

Issue/Year/DOI: Applied Physics B 123:215 (2017)
DOI: 10.1007/s00340-017-6794-8