World’s first digital laser in South Africa : What you need to know?

Its good to see South Africa united sharing good news, Researchers at South Africa's Council for Scientific and Industrial Research (CSIR) made it possible with development of 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.

CSIR announced the development of the world’s first digital laser at a presentation on Tuesday. Professor Andrew Forbes of the CSIR National Laser Centre leading the team that expected to spur numerous applications to improve the communication and health sectors

“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’.

“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 resonators,” says Forbes.

Sandile Ngcobo at the University of KwaZulu–Natal in South Africa and few buddies say they’ve worked out a way round this. And they’ve designed and built a device to test their idea.

(a) Schematic of the complex plane showing two phase-only values, A and B, lies on the unit circle (unit amplitude). The average of these is vector C, representing amplitude modulation as it is not on the unit circle.

The solution is simple. Instead of putting a spatial light modulator in front of the laser, they’ve built one in to the device, where it acts as the mirror at one end of the cavity. In this way, the spatial light modulator shapes the beam as it is being amplified.

The result is that the beam is already shaped in the required way when it emerges from the laser cavity. “We have demonstrated a novel digital laser that allows arbitrary intra-cavity laser beam shaping to be executed on the fly,” say Ngcobo and co.

The big advantage of all this is that the spatial light modulator generates patterns electronically. That allows these guys to change the beam shape at the touch of a button and without any of the time-consuming set up required with other methods.

They call their device a digital laser, because the beam can be shaped electronically with a computer. That’s the first time such a machine has been built.

The results are interesting. In putting the digital laser though its paces, they’ve shown how it can produce all kinds of beams with different shapes.