Researchers at South Africa's Council for Scientific and Industrial Research (CSIR) have developed a world-first digital laser that could be a game-changer in the field, paving the way for new laser applications in areas ranging from medicine to communications.
The team has shown that laser beams can be digitally controlled from within a laser device. Their findings have just been published in a prestigious journal, Nature Communications, in the following issue: Nature Communications 4, no 2289, 2 August 2013.
Announcing the breakthrough at media briefing in Pretoria on Tuesday, Science and Technology Minister Derek Hanekom said it was evidence of the country's potential for scientific innovation.
“This groundbreaking development is further evidence of the great potential we have in scientific innovation – that the world’s first digital laser should come from our country is testimony to the calibre of scientists that South Africa has,” says Minister of Science and Technology, Mr Derek Hanekom.
In conventional lasers, the shape of the light that comes out is either not controlled at all, or a single shape is selected by expensive optics. For example, when a medical doctor undertakes surgery, the beam must be appropriate for precision-cutting.
Alternatively, the laser light can be shaped after exiting the laser using a spatial light modulator – a liquid crystal display (LCD) that can be digitally addressed with grey-scale images representing the desired change to the light. The CSIR team has demonstrated for the first time that this can all be done inside the laser.
“Our digital laser uses the LCD as one of its mirrors that is fitted at one end of the laser cavity. Just as with LCD televisions, the LCD inside the laser can be sent pictures to display. When the pictures change on the LCD inside, the properties of the laser beams that exit the device change accordingly,” says Prof Andrew Forbes, leader of the mathematical optics research group.
The researchers have shown that this allows a purely digital control of what comes out of the laser (laser modes) in real-time, hence the name ‘digital laser’.
Sandile Ngcobo with the University of KwaZulu-Natal, and a team of researchers have successfully tested a laser that can change the shape of its beam without all of the labor involved of changing and recalibrating the add-ons. Forbes' team included doctoral student Liesl Burger, and post-doctoral fellow Dr Igor Litvin.
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