Sensors, switches and transducers
Technology of the F tu e
ROUND UP
R
esearchers at South Africa's
Council for Scientific and Industrial
Research (CSIR)
have developed the world's first digital laser.This
innovation is regarded as a milestone in laser technology and could
spur future laser-related innovations teamhas shown that laser beams
can be digitally controlled from within a laser device.
There is hardly a domain of our modern existence which does not
benefit from some form of laser technology.The domains range from
devices for laser lighting displays in entertainment to office equip-
ment such as laser printers, DVD players at home, barcode scanners
in the shops, surgical technology in hospitals or devices to cut and
weld industrial materials in factories.
“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 SouthAfrica has,” says Minister of Science andTechnol-
ogy, Mr Derek Hanekom.
Laser devices normally consist of mirrors, energy (light) and a cas-
ing containing a medium, for example crystal or glass.The medium
changes the frequency of the light to create a laser beam with the
perfect characteristics for these different applications.
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 Professor 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’.
“We showed that by sending an appropriate picture to the LCD,
any desired laser beam could be created inside the laser device.
This is a significant advancement from the traditional approach to
laser beam control, which requires costly optics and realignment of
the laser device for every beam change. Since this is all done with
pictures, the digital laser represents a paradigm shift for laser resona-
tors,” says Forbes.
In a ground-breaking experiment at the CSIR’s laboratories in Pre-
toria, the team programmed the LCD to play a video of a selection of
images representing a variety of desired laser modes.The result was
that the laser output changed in real-time from one mode shape to
another. “The dynamic control of laser modes could open up many
future applications, from communications to medicine. Our device
represents a new way of thinking about laser technology and we
see it as a new platform on which future technologies may be built,”
says Forbes. CSIR Researcher Sandile Ngcobo, who conducted the
breakthrough experimental work as part of his PhD studies, believes
the significance of the research is to demonstrate the ability within
the CSIR to lead innovation in this field.
"I believe the digital laser will be a 'disruptive' technology.This is
technology which may change the status quo and which could cre-
ate new markets and value networks within the next few years or
decade. The research into the digital laser continues. It adds to the
CSIR’s strong track record in the development of laser technology in
mathematical optics,” says Ngcobo.
Enquiries: Email
World's first digital laser – developed by researchers at the CSIR
The work was done in the mathematical optics group at the CSIR
National Laser Centre. The team was led by Professor Andrew Forbes,
chief scientist and research group leader, supported by post-doctoral
fellow, Dr Igor Litvin, and doctoral students, Sandile Ngcobo and
Liesl Burger. The CSIR Researcher, Sandile Ngcobo, performed the
breakthrough experimental work as part of his PhD studies.
Electricity+Control
December ‘13
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