Optical aberrations in gas lenses

Mafusire, Cosmas; Forbes, Andrew; Michaelis, M.M.; Snedden, Glen

doi:10.1117/12.862855

Cited by 3 publications

(6 citation statements)

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“…Our approach to characterizing the aberrations and turbulence in the SPGL is based on the angle-of-arrival slope correlation method, details of which can be found in [25,40,41]; a brief description of the experiment and some typical data is given in the appendix. Our results are summarized in figure 8.…”

Section: Spgl Characterizationmentioning

confidence: 99%

“…This demonstrates that, as predicted, the heating causes the beam to tip significantly in the −y direction. When the SPGL is rotated the density gradient (on average) becomes more symmetric about the centre, but random flow instabilities contribute significantly to tip and tilt errors on the wavefront [25]. Figure 9 maps the position of the beam centroid for regimes 1 and 2, where both graphs are normalized to the mean position of the beam in that regime.…”

Section: Beam Wandermentioning

confidence: 99%

“…In this study we make use of a low-budget and an easy to implement device in the form of a heated, spinning, metal pipe to create a 'thick' perturbing medium in the laboratory. The pipe introduces extensive tip-tilt and defocus distortions [23,24] and under stable conditions acts as a gradient-index (GRIN) medium, but instabilities in the flow result in random density fluctuations that have been suggested to follow the van Karman atmospheric turbulence model [25]. The device is tunable insofar as perturbations can be controlled by specifying the pipe wall temperature and pipe rotation speed.…”

Section: Introductionmentioning

confidence: 99%

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Propagation of orbital angular momentum carrying beams through a perturbing medium

Chaibi

Mafusire

Forbes

2013

J. Opt.

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The orbital angular momentum of light has been suggested as a means of information transfer over free-space, yet the detected optical vortex is known to be sensitive to perturbation. Such effects have been studied theoretically, in particular through turbulence. Here we demonstrate a simple apparatus to introduce turbulence-like distortions to optical fields propagating over a long path. We create vortex beams and observe their propagation through a heated spinning pipe, known to mimic the two primary atmospheric aberrations, namely tip-tilt and defocus. We use a digital decomposition tool to modally resolve the distorted vortex beam into its azimuthal components to observe the impact of the medium on the detection of the encoded vortex charge. Such techniques are useful in studies of free-space optical communication with orbital angular momentum.

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Section: Spgl Characterizationmentioning

confidence: 99%

Section: Beam Wandermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Propagation of orbital angular momentum carrying beams through a perturbing medium

Chaibi

Mafusire

Forbes

2013

J. Opt.

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“…Recently a more modern approach to understanding such devices has been completed, considering the interface of fluid dynamics with physical optics propagation and characterisation of laser beams (Mafusire et al, 2007;Mafusire et al, 2008a;Mafusire et al, 2008b;Mafusire et al, 2010a;Mafusire et al, 2010b). Using computational fluid dynamics (CFD) to simulate the density and velocity distributions inside the SPGL, one can deduce the phase change imparted to the light through the Gladstone-Dale law, thus making it possible to calculate optical aberrations at any plane along the beam's path.…”

Section: Gas Lensesmentioning

confidence: 99%

Fluid Dynamics, Computational Modeling and Applications

Juárez¹

2012

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received his Ph.D. in mathematics from the University of Houston (USA), in 1996. He also was a postdoctoral fellow and assistant visiting professor of the same institution during the period 1999-2002. Since 2002 he is full professor of applied mathematics at the Universidad Autonoma Metropolitana-Iztapalapa (UAM-I) in Mexico City, and currently is a Fellow of the National Research System in Mexico, level 2. He has participated in numerous research projects and published several research articles, reports, conference proceedings and book chapters, mainly in CFD, numerical solution of PDE, mathematical modeling and computer simulation. He has been supervisor of several graduate students, and has participated in numerous academic committees. It has also helped organize numerous national and international meetings in Mexico, and he has participated in many others abroad. Professor Juárez was recently elected member of the Main Board of the Mexican Mathematical Society for the period 2012-2014.

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“…Further improvements included operating the SPGL at pressures higher and lower than atmospheric pressure (Forbes, 1997) in order to control the focal length, and careful characterisation of the temperature distribution inside the pipe (Lisi, 1994). Recently a more modern approach to understanding such devices has been completed, considering the interface of fluid dynamics with physical optics propagation and characterisation of laser beams (Mafusire et al, 2007;Mafusire et al, 2008a;Mafusire et al, 2008b;Mafusire et al, 2010a;Mafusire et al, 2010b). Using computational fluid dynamics (CFD) to simulate the density and velocity distributions inside the SPGL, one can deduce the phase change imparted to the light through the Gladstone-Dale law, thus making it possible to calculate optical aberrations at any plane along the beam's path.…”

Section: Wwwintechopencommentioning

confidence: 99%