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Browsing by Author "Forbes, A"

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  • Von Bergmann, H; Forbes, A; Roberts, T; Botha, L (The International Society for Optical Engineering, 2007)
    In this paper the author’s present results on the influence of acoustic waves on the output laser beam from high repetition rate TEA CO2 lasers. The authors show that acoustic waves generated inside the cavity lead to ...
  • Mthunzi, P; Forbes, A; Hawkins, D; Abrahamse, H; Karsten, AE (The International Society for Optical Engineering, 2005)
    A variety of strategies have been utilised for prevention and treatment of chronic wounds such as leg ulcers, diabetic foot ulcers and pressure sores1. Low Level Laser Therapy (LLLT) has been reported to be an invaluable ...
  • Mthunzi, P; Forbes, A; Hawkins, D; Abrahamse, H; Karsten, AE (2006-07)
    A variety of strategies have been utilised for prevention and treatment of chronic wounds such as leg ulcers, diabetic foot ulcers and pressure sores. Low Level Laser Therapy (LLLT) has been reported to be an invaluable ...
  • Forbes, A; Botha, L; Du Preez, N; Drake, T (The International Society for Optical Engineering, 2007)
    Laser ultrasonics is currently the optimal method for non-destructive testing of composite materials in the aerospace industry. The process is based on a laser-generated ultrasound wave which propagates inside the composite. ...
  • Naidoo, Darryl; Forbes, A; Aït-Ameur, K; Fromager, M (SPIE, 2011-01)
    A method of decomposing a dual-directional laser beam into a forward propagating field and a backward propagating field for an apertured plano-concave cavity is presented. An intra-cavity aperture is a simple method of ...
  • Ngcobo, S; Ait-Ameur, K; Forbes, A (2012-08)
    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 ...
  • Naidoo, Darryl; Aït-Ameur, K; Brunel, M; Forbes, A (Springer Verlag, 2012)
    In this paper we demonstrate experimentally the intra-cavity generation of a coherent superposition of Laguerre–Gaussian modes of zero radial order but opposite azimuthal order. The superposition is created with a simple ...
  • Naidoo, Darryl; Litvin, I; Laskin, A; Forbes, A (SPIE Proceedings, 2014-02)
    We explore an intra-cavity beam shaping approach to generate a Gaussian distribution by the metamorphosis of a Gaussian beam into a flat-top distribution on opposing mirrors. The concept is tested external to the cavity ...
  • Naidoo, Darryl; Aït-Ameur, K; Forbes, A (SPIE, 2011-08)
    In this paper the authors explore vortex beams and in particular the generation of single LG0l modes and superpositions thereof. Vortex beams carry orbital angular momentum (OAM) and this intrinsic property makes them ...
  • Litvin, IA; Khilo, NA; Forbes, A; Belyi, VN (Society of Photo-Optical Instrumentation Engineers, 2009-08)
    In this paper the researchers report on two resonator systems for producing LDBLBs with arbitrary initial parameters. First resonator system is based on doublet of divergence and convergence lenses with spherical aberration. ...
  • Litvin, IA; Loveday, PW; Long, CS; Kazak, NS; Belyi, V; Forbes, A (Society of Photo-Optical Instrumentation Engineers (SPIE), 2008-08)
    There are many applications in which a laser beam with a flat–top intensity profile would be ideal, as compared to a laser beam with a non–uniform energy distribution. Standard stable optical resonators will unfortunately ...
  • Litvin, IA; Forbes, A (Society of Photo-Optical Instrumentation Engineers, 2009-08)
    In this paper the authors present the analytical and numerical analyses of two new resonator systems for generating flat–top–like beams. Both approaches lead to closed form expressions for the required cavity optics, but ...
  • Litvin, IA; Khilo, NA; Forbes, A; Belyi, VN (Optical Society of America, 2010-02)
    The authors report on two resonator systems for producing Bessel–like beams with longitudinally dependent cone angles (LDBLBs). Such beams have extended propagation distances as compared to conventional Bessel– Gauss beams, ...
  • Belyi, VN; Kazak, NS; Khilo, NA; Forbes, A; Ropot, PI (Society of Photo-optical Instrumentation Engineers (SPIE), 2009-08)
    The spectrum of spatial frequencies (SFS) of Bessel beams properties emerging at their spatial localization is investigated. The case, when limiting aperture has a circular shape and a center at any distance from the optical ...
  • Hamadou Ibrahim, A; Roux, FS; McLaren, M; Forbes, A; Konrad, T (2013-06)
    This is a power point presentation questioning the feasablility of free space quantum communication with the OAM state of light. Presented June 2013
  • Burger, L; Forbes, A (Optical Society of America, 2008-08)
    The authors apply a new method of modeling Porro prism resonators, using the concept of rotating loss screens, to study stable and unstable Porro prism resonator. They show that the previously observed petal–like modal ...
  • Trichili, A; Mhlanga, T; Naidoo, Darryl; Dudely, A; Zghal, M; Forbes, A (SPIE, 2014-08-17)
    We analyze the effect of atmospheric turbulence on the propagation of multiplexed Laguerre Gaussian modes. We present a method to multiplex Laguerre Gaussian modes using digital holograms and decompose the resulting field ...
  • Forbes, A; Schulze, C; Flamm, D; Dudley, Angela L; Duparre, M (Optical Society of America, 2013-04)
    We show how laser beam characterization may be done in real-time with digital holograms. We illustrate the power of the techniques by applying them to a variety of laser sources, from fibers to solid-state.
  • Forbes, A (2006-08)
    Many analytical techniques exist to explore the propagation of certain laser beams in free space, or in a linearly absorbing medium. When the medium is nonlinearly absorbing the propagation must be described by an iterative ...
  • Masina, BN; Bodkin, R; Mwakikunga, B; Forbes, A (SPIE, 2011-08)
    This paper presents an implementation of a laser beam shaping system for both heating a diamond tool and measuring the resulting temperature optically. The influence the initial laser parameters have on the resultant ...