Lasers bridge the rainbow

Annealing a semiconductor structure enables researchers to tune the color of a laser into the orange parts of the spectrum .

© 2015 KAUST

Micrometer-scale lasers that emit orange light have been created by researchers at KAUST. Orange laser light is useful for diverse applications ranging from horticulture to optical communications, but previous attempts to create an orange laser were not commercially practical. 

Conventional lasers that produce orange-yellow light use a gas or a nonlinear crystal as the light-producing medium and can be as small as tens of centimeters or can fill a room. Semiconductors lasers, however, are compact, and can be just a few micrometers in size. 

The drawback of the semiconductor approach is that the color of light produced by such devices is determined by the intrinsic properties of the material. Because there are only a few suitable semiconducting materials, there is a limited selection of emission wavelengths. 

Boon Ooi of the Computer, Electrical and Mathematical Science and Engineering Division, and his colleagues produced a laser that creates orange light by making subtle compositional changes of a structure based on InAlAsP materials.

“We have fabricated high-performance semiconductor lasers that bridge the wavelength gap of visible light semiconductor lasers,” Ooi said.

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