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Browsing by Author "Forbes, A"

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  • Mafusire, C; Forbes, A; Snedden, Glen C; Mahlase, ACK; Michaelis, MM; Mathuthu, M (2006-07)
    When a heated pipe is rotated, the dynamics of the gas inside exhibit properties reminiscent of a solid-state positive lens. The properties are a result of a parabolic distribution of refractive index in the pipe which is ...
  • Litvin, IA; Forbes, A (Optical Society of America, 2009-10)
    The authors outline a resonator design that allows for the selection of a Gaussian mode by diffractive optical elements. This is made possible by the metamorphosis of a Gaussian beam into a flat-top beam during propagation ...
  • Mafusire, C; Forbes, A (Optical Society of America, 2011-07)
    The authors outline a theory for the calculation of the beam quality factor of an aberrated laser beam. They provide closed form equations that show that the beam quality factor of an aberrated Gaussian beam depends on all ...
  • Li, Y; Dudley, Angela L; Mhlanga, T; Escutia, MJ; Forbes, A (SPIE Proceedings, 2013-08)
    We experimentally generate non-diffracting vector vortex beams by using a Spatial Light Modulator (SLM) and an azimuthal birefringent plate (q-plate). The SLM generates scalar Bessel beams and the q-plate converts them to ...
  • Dudley, Angela L; Lib, Y; Mhlanga, T; Escuti, M; Forbes, A (SPIE Proceedings, 2014-03)
    We demonstrate how to create non-diffracting vector Bessel beams by implementing a spatial light modulator (SLM) to generate scalar Bessel beams which are then converted into vector fields by the use of an azimuthally-varying ...
  • Dudley, Angela L; Li, Y; Mhlanga, T; Escuti, M; Forbes, A (Optical Society of America, 2013-09)
    Nondiffracting vector Bessel beams are of considerable interest due to their nondiffracting nature and unique high-numerical-aperture focusing properties. Here we demonstrate their creation by a simple procedure requiring ...
  • Vasilyeu, R; Dudley, Angela L; Khilo, N; Forbes, A (Optical Society of America, 2009-10)
    An experimental setup to generate a superposition of higher-order Bessel beams by means of a spatial light modulator and ring aperture is presented. The experimentally produced fields are in good agreement with those ...
  • Vasilyeu, R; Dudley, Angela L; Khilo, N; Forbes, A (Optical Society of America, 2009-12)
    The authors report the first experimental generation of the superposition of higher-order Bessel beams, by means of a spatial light modulator (SLM) and a ring slit aperture. They present illuminating a ring slit aperture ...
  • Forbes, A; Du Preez, N; Litvin, IA; Botha, LR (South African Institute of Physics (SAIP), 2009-07)
    Generation and application of high power flattened Gaussian beams. Presented at the 54th Annual Conference of the South African Institute of Physics (SAIP) 2009.
  • Belyi, VN; Khilo, NA; Forbes, A; Ryzhevich, AA (Society of Photo-optical Instrumentation Engineers (SPIE), 2009-08)
    Linear and nonlinear processes of transferring optical singularities from anisotropic crystals onto the wavefront of Bessel light beams (BLBs) are investigated. The generation of high-order vortices at the propagation of ...
  • Hendriks, A; Naidoo, Darryl; Roux, FS; Löpez-Mariscal, C; Forbes, A (SPIE, 2012-08)
    Phase-only spatial light modulators are now ubiquitous tools in modern optics laboratories, and are often used to generate so-called structured light. In this work we outline the use of a phase-only spatial light modulator ...
  • Ngcobo, S; Ait-Ameur, K; Forbes, A (2012-07)
    This work deals with the generation of symmetrical high order Laguerre Gaussian modes. These high order Laguerre-Gaussian beams are generated by forcing the laser using an annular binary Diffractive Optical Element whose ...
  • Ait-Ameur, K; Naidoo, Darryl; Ngcobo, S; Fromager, M; Litvin, I; Hasnaoui, A; Harfouche, A; Forbes, A (SPIE, 2015-02)
    A great number of laser applications need in place of the usual Gaussian beam a flat-top intensity profile in the focal plane of a focusing lens. In general the transformation of the laser beam from the Gaussian to the ...
  • McLaren, M; Roux, FS; Forbes, A (SAIP, 2012-07)
    This presentation highlights the increasing interest in quantum and high dimensional entanglement.
  • Ngcobo, S; Forbes, A; Ait-Ameur, K (2012-07)
    The transformation of a single mode TEM00 Gaussian beam by forcing the laser to operate into a symmetrical single mode higher order TEMp0 Laguerre Gaussian beam intensity distribution is very useful in improving and ...
  • Du Preez, NC; Forbes, A; Botha, LR (Society of Photo-Optical Instrumentation Engineers (SPIE), 2009-09)
    In this paper researchers present the design of a CO2 laser resonator that produces as the stable transverse mode a super–Gaussian laser beam. The resonator makes use of an intra–cavity diffractive mirror and a flat output ...
  • Mafu, M; Dudley, Angela L; Goyal, S; Giovannini, D; McLaren, M; Padgett, MJ; Konrad, T; Petruccione, F; Lutkenhaus, N; Forbes, A (American Physical Society, 2013-09)
    We present an experimental study of higher-dimensional quantum key distribution protocols based on mutually unbiased bases, implemented by means of photons carrying orbital angular momentum. We perform (d + 1) mutually ...
  • Ismail, Y; Barnes, G; Mhlanga, T; Belyi, V; Forbes, A (SPIE, 2010-08)
    As in the case of zero-order Bessel beam being produced by illuminating an axicon with a Gaussian beam, higher-order Bessel beams are generated by substituting the Gaussian beam with a Laguerre Gaussian (LG) beam. These ...
  • Rosales-Guzman, C; Trichili, A; Dudley, Angela; Ndagano, B; Salem, AB; Zghal, Mourad; Forbes, A (SPIE, 2016-09)
    Current optical communication technologies are predicted to face a bandwidth capacity limit in the near future. The nature of the limitation is fundamental rather than technological and is set by nonlinearities in optical ...
  • Burger, L; Litvin, I; Ngcobo, S; Forbes, A (SPIE, 2014-03)
    The beam from a laser resonator is determined by the optical elements it contains. Most commonly, these consist of two spherical mirrors, but phase- and amplitude-modulating elements can also be included to produce custom ...