Since the creation of the first working laser scientists have fashioned these light sources from substances ranging from neon to sapphire. Silicon, however, was not considered a candidate. Its structure would not allow for the proper line-up of electrons needed to get this semiconductor to emit light.
In the past, scientists have chemically altered silicon or smashed it into dust-like particles to generate light emission. But more light was naturally lost than created. Now a trio of Brown University researchers, led by engineering and physics professor Jimmy Xu, has made the impossible possible. The team has created the first directly pumped silicon laser.
They did it by changing the atomic structure of silicon itself. To get the job done, the team created a template, or “mask,” of anodized aluminum. About a millimeter square, the mask features billions of tiny holes, all uniformly sized and exactly ordered. Placed over a bit of silicon then bombarded with an ion beam, the mask served as a sort of stencil, punching out precise holes and removing atoms in the process. The silicon atoms then subtly rearranged themselves near the holes. The result: weak but true laser light.
Right now, the possible is not yet practical. In order to make his silicon laser commercially viable, Xu said, it must be engineered to be more powerful and to operate at room temperature. At the moment, it works at 200°C below zero. But a material with the electronic properties of silicon and the optic properties of a laser would find uses in both the electronics and communications industries, helping to make faster, more powerful computers or fiber optic networks.
COMPAMED.de; Source: Brown University