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Cosmas Mafusire |
For the first time, a special instrument called a Shack-Hartmann wavefront sensor has been used to analyse the wavefront and determine the optical turbulence introduced by a spinning pipe gas lens (SPGL) to a laser beam. The paper: Optical aberrations in a spinning pipe gas and one of the associated experimental videos have been published in the highest-ranked optics journal in the world by the Institute for Scientific Information (ISI), Optics Express. The journal used this paper as its 'show-case' on its web site for a period in July.
Cosmas Mafusire, a PhD student at the CSIR National Laser Centre, made this scientific breakthrough, which has provided interesting discoveries of relevance to both the world of optics, specifically laser propulsion, and to aerodynamics.
SPGLs provide a way of understanding how laser beams behave in a turbulent medium. Mafusire says, "In many cases, laser beams propagate in media that are not of uniform density, hence we need to measure the changes to beams caused by such media. We have worked with a fluid dynamics expert at CSIR Defence, Peace, Safety and Security, Glen Snedden, who has developed numerical models of the gas flow in the pipe. These models are computer-generated and allow for the changes to be quantified accurately." Mafusire is part of the CSIR mathematical optics research group.
He says, "Very few feasible solutions currently exist for the focusing of high-power laser systems, and it is possible that the loss in beam quality can be compensated for by the increase in transmission power that can be delivered. There is also a need in many delivery systems for long focal length (weak) lenses, for example, in laser propulsion or long-range target designating. This may be the area where the SPGL has a significant role to play."
Asked where to from now, Mafusire says, "It's a question of trying; we will continue to investigate all variables by experimenting with different sizes, conditions and lengths to take this research further." Research group leader Dr Andrew Forbes, laser propulsion expert Max Michaelis and Snedden are co-authors of the paper.
Enquiries: CSIR Communication
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