The CSIR’s laser research capacity has just received a boost with the opening of its second femtosecond laboratory, a mere two years since the first lab’s establishment. Femtosecond science involves the use of high-tech laser systems delivering ultra short femtosecond pulses with high peak intensities.
Speaking at the opening of the new lab, research group leader Dr Anton du Plessis said, “Femtosecond science research is a long-term programme at the CSIR aimed at developing world-class expertise and facilities in this new field, which is at the cutting edge of scientific research. A femtosecond is minuscule – it is equal to one millionth of a billionth of a second. Just imagine – the ratio between the perceived age of the earth (4,55 billion years: 4 450 000 000 000) and a minute is approximately the same as that between a minute and a femtosecond. As atoms move in femtoseconds from one position to another, they break and form bonds in this time scale. With this technology, we can follow atoms as they move and react, much as in a video.”
To date, the research group has made major strides; the opening of this lab being of particular relevance. Another significant achievement was the successful completion of a major industrial contract in which the feasibility of using femtosecond technology was investigated. In addition, four students have received their Masters degrees, one student won a prize at the annual South African Institute of Physics conference and two research papers will be published in the next few months.
Femtosecond science has many applications, according to Du Plessis: “This technology is highly interdisciplinary and can be used in diverse fields such as physics, biology, chemistry and even for micro drilling of various materials such as fibres. As unbelievable as it may sound, we were able to drill the letters ‘NLC’ on a single strand of hair.”
The femtosecond science research group forms part of the CSIR National Laser Centre. Its focus is on ‘coherent control’, which involves the use of coherent excitations (using a femtosecond laser) to control matter. The ultimate goal is to rearrange a molecule into new compounds by using only light. In this work, the group studies femtosecond laser pulse-induced molecular dissociation in a laser ionisation time of flight mass spectrometer. The next step is to apply these ‘lessons’ to mixtures of gases in a high pressure reaction cell and thereby attempt to induce and control chemical reactions to produce selective reaction products, which would otherwise have taken place only at high temperatures and with mixtures of reaction products. The group has received interest for this type of work from numerous industry role-players. Du Plessis adds, “An ambitious project we hope to start soon is the study of laser-induced water splitting for hydrogen generation.”
In another endeavour, the team is embarking on the use of the femtosecond lasers for the deactivation of viruses. “With a femtosecond laser, indications are that we will be able to selectively destroy or deactivate viruses without any damage or mutation to other cells, for example blood cells. This project aims to understand the physical mechanisms of the process and prove the principle in a lab setup. This work could play a major role in a future new dialysis treatment for patients with the human immunodeficiency virus, for example, although the technique could have countless other applications, not only in the medical field,” explains Du Plessis. The team is currently culturing its own colonies of E.Coli. bacteria and initial experiments will be done with viruses that affect only bacteria, not humans (T4 and M13 bacteriophages).
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