14 DAY TRIAL // Ever since lasers first appeared, efforts have been oriented towards making them more efficient, smaller, larger, or more powerful. While some laser facilities boast instruments spanning hundreds of feet in size, some scientists are working on the micro- and nanoscale, to create devices with applications in handling single molecules or nanostructures. Recently, scientists at the University of California in Berkeley (UCB) have devised the smallest semiconductor laser in the world, again innovating this field of research, ScienceDaily reports.
The innovation is that much more important, as the team has not only managed to shine light in such a small space, but has also been able to sustain it as it has moved along. This essentially means that it has developed a laser. “This work shatters traditional notions of laser limits, and makes a major advance toward applications in the biomedical, communications and computing fields,” UCB Nanoscale Science and Engineering Center Director and Professor of Mechanical Engineering Xiang Zhang explains. He is also the leader of the team behind the new laser. The work was funded by the US National Science Foundation (NSF).
In a paper published in the August 30th advanced online issue of the respected scientific journal Nature, the experts describe that the new class of semiconductor lasers could be successfully used at the nanoscale in the future for handling, influencing, or characterizing single DNA molecules. Such an achievement could further research capabilities in a large number of fields related to medicine and microbiology investigations. Optics-based computers could also communicate with each other a lot faster than they are able to now, as would the components inside each of them.
For the new laser to be able to sustain light and prevent it from dissipating, the researchers constructed it out of cadmium sulfide nanowire and a silver surface, which were separated by an insulating gap only five nanometers wide. “When you are working at such small scales, you do not have much space to play around with. In our design, the nanowire acts as both a confinement mechanism and an amplifier. It's pulling double duty,” the co-author of the Nature paper, Rupert Oulton, says. He first theorized this approach in 2008, and has worked in Zhang's lab to prove it since.