This schematic illustrates the novel nanosheet with three parallel segments, of three elementary colors. The device is capable of lasing in any visible color. When the total field is collected, a white color emerges. Photograph: ASU/Nature Nanotechnology
SPR: Scientists at Arizona State University have created the world’s first ‘White Laser’ using a special semiconductor and nanoscale technology.
It has been more than a century since we moved from lanterns to incandescent bulbs, and then to more recent CFLs and LEDs. Going by the recent developments, it seems these light sources too are going to be phased out soon.
Arizona State University scientists have created a ‘white laser’ that is brighter and more efficient than most LEDs in use today. Lasers are powerful energy beams and can emit up to 2 quadrillion watts of power.
A Laser is based on the principle of coherence, i.e. Laser emits narrow bandwidth wavelengths, or you can say specific frequencies. Whereas, the white light comprises of a wider wavelength and contains a large number of light frequencies.
So, creating a white laser is an irony, but there are ways to generate a laser that seems as if it’s emitting ‘white’ color, by combining lasers of different colors. The scientists at ASU had used nanomaterials that allow colored beams to combine and become a ‘white laser’ beam. The colors, as you must have anticipated by now are red, blue, and green.
The scientists from the ASU’s Ira A. Fulton Schools of Engineering developed a sheet of a nanoscale semiconductor based on a quaternary alloy of ZnCdSSe. With this semiconductor sheet, the scientists were able to combine the three colored lasers to form a pure ‘white laser’.
Controlling the proportions of each colored laser was the tricky part. For that, the scientists adjusted the lattice pattern of the semiconductor, i.e. the lattice constant (atomic distance) was tampered to produce a uniform required area. So, the result was a single material with different lattices that could produce a white light laser.
Lasers have been in the picture since 1960 and seen mostly as death rays, laser swords, or a cutting edge military weapon. But now, the laser technology is even being tested by Facebook to beam Internet at 10 Gbps through drones.
This development could have tremendous practical applications as per the ASU scientists. The white laser can be used in display screens such as televisions and monitors. The color range of the laser is 70% greater, more accurate and vivid than the usual. Also, the White Laser is much brighter and efficient than the regular light sources.
Lasers can also be used in futuristic optical communication which are much faster, as in optical versions of Wi-Fi.
White Laser has been developed, but as you have seen it requires an incredible precision and a nano-scale technology. So, it is yet to become practical. To become a common light source, a white laser should be able to work from the available batteries. As of now, it is powered with a separate laser.
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