Generation and self-healing of vector Bessel-Gauss beams with variant state of polarizations upon propagation

Author(s):

Peng Li and Yi Zhang and Sheng Liu and Huachao Cheng and Lei Han and Dongjing Wu and Jianlin Zhao

Abstract:

“We propose a generalized model for the creation of vector Bessel-Gauss (BG) beams having state of polarization (SoP) varying along the propagation direction. By engineering longitudinally varying Pancharatnam-Berry (PB) phases of two constituent components with orthogonal polarizations, we create zeroth- and higher-order vector BG beams having (i) uniform polarizations in the transverse plane that change along z following either the equator or meridian of the Poincaré sphere and (ii) inhomogeneous polarizations in the transverse plane that rotate during propagation along z. Moreover, we evaluate the self-healing capability of these vector BG beams after two disparate obstacles. The self-healing capability of spatial SoP information may enrich the application of BG beams in light-matter interaction, polarization metrology and microscopy.”

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Publication: Optics Express
Issue/Year: Optics Express Vol. 25, Issue 5, pp. 5821-5831 (2017)
DOI: 10.1364/OE.25.005821

Diffraction-free light droplets for axially-resolved volume imaging.

Author(s):

Antonacci, G. and Domenico, G. Di and Silvestri, S. and DelRe, E. and Ruocco, G.

Abstract:

“An ideal direct imaging system entails a method to illuminate on command a single diffraction-limited region in a generally thick and turbid volume. The best approximation to this is the use of large-aperture lenses that focus light into a spot. This strategy fails for regions that are embedded deep into the sample, where diffraction and scattering prevail. Airy beams and Bessel beams are solutions of the Helmholtz Equation that are both non-diffracting and self-healing, features that make them naturally able to outdo the effects of distance into the volume but intrinsically do not allow resolution along the propagation axis. Here, we demonstrate diffraction-free self-healing three-dimensional monochromatic light spots able to penetrate deep into the volume of a sample, resist against deflection in turbid environments, and offer axial resolution comparable to that of Gaussian beams. The fields, formed from coherent mixtures of Bessel beams, manifest a more than ten-fold increase in their undistorted penetration, even in turbid milk solutions, compared to diffraction-limited beams. In a fluorescence imaging scheme, we find a ten-fold increase in image contrast compared to diffraction-limited illuminations, and a constant axial resolution even after four Rayleigh lengths. Results pave the way to new opportunities in three-dimensional microscopy.”

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Publication: Scientific Reports
Issue/Year: Scientific Reports volume 7, Article number: 17 (2017)
DOI: 10.1038/s41598-017-00042-w

Bessel beams with spatial oscillating polarization

Author(s):

Fu, Shiyao and Zhang, Shikun and Gao, Chunqing

Abstract:

“Bessel beams are widely used in optical metrology mainly because of their large Rayleigh range (focal length). Radial/azimuthal polarization of such beams is of interest in the fields of material processing, plasma absorption or communication. In this paper an experimental set-up is presented, which generates a Bessel-type vector beam with a spatial polarization, oscillating along the optical axis, when propagating in free space. A first holographic axicon (HA) HA1 produces a normal, linearly polarized Bessel beam, which by a second HA2 is converted into the spatial oscillating polarized beam. The theory is briefly discussed, the set-up and the experimental results are presented in detail.”

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Publication: Scientific Reports
Issue/Year: Scientific Reports volume 6, Article number: 30765 (2016)
DOI: 10.1038/srep30765

Experimental demonstration of 3D accelerating beam arrays

Author(s):

Xianghua Yu and Runze Li and Shaohui Yan and Baoli Yao and Peng Gao and Guoxia Han and Ming Lei

Abstract:

“Accelerating beams have attracted much attention in the frontiers of optical physics and technology owing to their unique propagation dynamics of nondiffracting, self-healing, and freely accelerating along curved trajectories. Such behaviors essentially arise from the particular phase factor occurring in their spatial frequency spectrum, e.g., the cubic phase associated to the spectrum of Airy beam. In this paper, we theoretically and experimentally demonstrate a sort of accelerating beam arrays, which are composed of spatially separated accelerating beams.
By superimposing kinoforms of multifocal patterns into the spatial frequency spectrum of accelerating beams, different types of beam arrays, e.g., Airy beam arrays and two-main-lobe accelerating beam arrays, are generated and measured by scanning a reflection mirror near the focal region along the optical axis. The 3D intensity patterns reconstructed from the experimental data present good agreement with the theoretical counterparts. The combination of accelerating beams with optical beam arrays proposed here may find potential applications in various fields such as optical microscopes, optical micromachining, optical trapping, and so on.”

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Publication: Applied Optics
Issue/Year: Applied Optics Volume 55, Issue 11 pp. 3090-3095 (2016)
DOI: 10.1364/ao.55.003090

Digital generation of shape-invariant Bessel-like beams

Author(s):

Igor A. Litvin and Thandeka Mhlanga and Andrew Forbes

Abstract:

“Bessel beams have been extensive studied to date but are always created over a finite region inside the laboratory. Means to overcome this consider multi-element refractive designs to create beams that have a longitudinal dependent cone angle, thereby allowing for a far greater quasi non–diffracting propagation region. Here we outline a generalized approach for the creation of shape-invariant Bessel-like beams with a single phase-only element, and demonstrate it experimentally with a phase-only spatial light modulator. Our experimental results are in excellent agreement with theory, suggesting an easy-to-implement approach for long range, shape-invariant Bessel-like beams.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol 23, Issue 6, pp. 7312- 7319 (2018)
DOI: 10.1364/OE.23.007312

Dark-hollow optical beams with a controllable shape for optical trapping in air

Author(s):

Porfirev, A. P. & Skidanov, R. V.

Abstract:

“A technique for generating dark-hollow optical beams (DHOBs) with a controllable cross-sectional intensity distribution is proposed and studied both theoretically and experimentally. Superimposed Bessel beams were used to generate such DHOBs. Variation of individual beam parameters enables the generation of Bessel-like non-diffracting beams. This technique allows the design of transmission functions for elements that shape both non-rotating and rotating DHOBs. We demonstrate photophoresis-based optical trapping and manipulation of absorbing air-borne nanoclusters with such beams.”

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Publication: Optics Express
Issue/Year: Optics Express, Volume 23; Number 7; Pages 8373; 2015
DOI: 10.1364/oe.23.008373

Detection of Bessel beams with digital axicons

Author(s):

Abderrahmen Trichili and Thandeka Mhlanga and Yaseera Ismail and Filippus S. Roux and Melanie McLaren and Mourad Zghal and Andrew Forbes

Abstract:

“We propose a simple method for the detection of Bessel beams with arbitrary radial and azimuthal indices, and then demonstrate it in an all-digital setup with a spatial light modulator. We confirm that the fidelity of the detection method is very high, with modal cross-talk below 5%, even for high orbital angular momentum carrying fields with long propagation ranges. To illustrate the versatility of the approach we use it to observe the modal spectrum changes during the self-reconstruction process of Bessel beams after encountering an obstruction, as well as to characterize modal distortions of Bessel beams propagating through atmospheric turbulence.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 22 , Issue 14, pp. 17553- 17560 (2014)
DOI: 10.1364/OE.22.017553

Direct measurement of a 27-dimensional orbital-angular-momentum state vector

Author(s):

Malik, Mehul and Mirhosseini, Mohammad and Lavery, Martin P. J. and Leach, Jonathan and Padgett, Miles J. and Boyd, Robert W.

Abstract:

“The measurement of a quantum state poses a unique challenge for experimentalists. Recently, the technique of ‘direct measurement’ was proposed for characterizing a quantum state in situ through sequential weak and strong measurements. While this method has been used for measuring polarization states, its real potential lies in the measurement of states with a large dimensionality. Here we show the practical direct measurement of a high-dimensional state vector in the discrete basis of orbital angular momentum. Through weak measurements of orbital angular momentum and strong measurements of angular position, we measure the complex probability amplitudes of a pure state with a dimensionality, d=27. Further, we use our method to directly observe the relationship between rotations of a state vector and the relative phase between its orbital-angular-momentum components. Our technique has important applications in high-dimensional classical and quantum information systems and can be extended to characterize other types of large quantum states.”

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Publication: Nature Communications
Issue/Year: Nature Communications volume 5, Article number: 3115 (2014)
DOI: 10.1038/ncomms4115

Optical eigenmodes; exploiting the quadratic nature of the energy flux and of scattering interactions

Author(s):

Mazilu, Michael and Baumgartl, J and Kosmeier, S and Dholakia, K

Abstract:

“We report a mathematically rigorous technique which facilitates the optimization of various optical properties of electromagnetic fields in free space and including scattering interactions. The technique exploits the linearity of electromagnetic fields along with the quadratic nature of the intensity to define specific Optical Eigenmodes (OEi) that are pertinent to the interaction considered. Key applications include the optimization of the size of a focused spot, the transmission through sub-wavelength apertures, and of the optical force acting on microparticles. We verify experimentally the OEi approach by minimising the size of a focused optical field using a superposition of Bessel beams.”

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Publication: Optics Express
Issue/Year: Optics Express Volume 19, Issue 2 pp.933-945 (2011)
DOI: 10.1364/OE.19.000933

Three-dimensional parallel holographic micropatterning using a spatial light modulator

Author(s): Nathan J. Jenness, Kurt D. Wulff, Matthew S. Johannes, Miles J. Padgett, Daniel G. Cole, and Robert L. Clark

Abstract:

“We present a micropatterning method for the automatic transfer and arbitrary positioning of computer-generated three-dimensional structures within a substrate. The Gerchberg-Saxton algorithm and an electrically addressed spatial light modulator (SLM) are used to create and display phase holograms, respectively. A holographic approach to light manipulation enables arbitrary and efficient parallel photo-patterning. Multiple pyramidal microstructures were created simultaneously in a photosensitive adhesive. A scanning electron microscope was used to confirm successful replication of the desired microscale structures. ”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 16, Issue 20, pp. 15942-15948 (2008)
DOI: 10.1364/OE.16.015942