Browsing by Author "Burger, Liesl"

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    Novel implementation of a phase-only spatial light modulator for laser beam shaping
    (Stellenbosch : Stellenbosch University, 2016-03) Burger, Liesl; Forbes, Andrew; Litvin, Igor; Rohwer, Erich G.; Stellenbosch University. Faculty of Science. Dept. of Physics
    ENGLISH ABSTRACT : The phase-only spatial light modulator (SLM) has revolutionized the field of laser beam shaping. In this thesis we describe in detail the considerations necessary to build a “digital laser” which incorporates an SLM into a laser cavity as an intracavity element to dynamically generate a wide variety of custom beams. We then present a theoretical analysis of the healing of petal-like (or Laguerre-Gaussian) beams using rotational considerations, and using digital laser technology to demonstrate this healing experimentally. We extend our investigation into self-healing beams with the theoretical derivation of a new type of Bessellike beams, which retains a concentric ring structure on propagation, and which self-heal axially. These beams are generated using an SLM, and self-healing is demonstrated experimentally.
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    Simulating atmospheric turbulence using a phase-only spatial light modulator
    (Academy of Science of South Africa, 2008) Burger, Liesl; Litvin,Igor A.; Forbes, Andrew
    Demonstration of the effect of atmospheric turbulence on the propagation of laser beams is traditionally a difficult task. This is due to the complexities of long-distance measurements and the scarcity of suitable laser wavelengths in atmospheric transmission windows. We demonstrate the simulation of atmospheric turbulence in the laboratory using a phase-only spatial light modulator. We illustrate the advantages of this approach, as well as some of the limitations, when using spatial light modulators for this application. We show experimental results demonstrating these limitations, and discuss the impact they have on the simulation of various turbulence strengths.