14 DAY TRIAL // A group of investigators at the University of California in San Diego (UCSD), led by the head of the Ultrafast and Nanoscale Optics Group, Yeshaiahu Fainman, announced recently the development of the smallest sub-wavelength laser ever. In addition to this mark, the team also broke a new record, as they produced the first such device that doesn't require cryogenic cooling. Generally, lasers that emit light and wavelengths larger than their own size can only operate at extremely low temperatures, Technology Review reports.
A sub-wavelength laser is a type of laser that has a size smaller than the wavelength of the light it produces. In the case of the instrument developed at the UCSD, the machinery itself is only one cubic micron in size. According to Fainman, it should theoretically be possible to cram many such devices together in a more complex array, without the individual lasers interfering with each other in any way. If this can be achieved, then a new generation of faster optical communications devices could be just around the corner, the team says.
Dense arrays of sub-wavelength lasers could therefore become the underlying technology of tomorrow's telecommunications, Fainman argues. He says that the instrument was derived from another type of laser, called a microdisc laser. This is a device consisting of a disk-shaped enclosure, and several types of materials inside. The entire ensemble is then optically pumped using a larger laser that makes photons inside bounce around in the disk, and among its materials, before finally being released. The team explains that adding small amounts of metal to the microdisc results in effective isolation, preventing interferences with nearby, similar devices from occurring.
“This is very exciting work, and introduces important advances in the new field of nanolasers. Making use of metallic layers and clever design geometries has allowed this group to begin to build refinements into these structures that will expand how these devices are used in communications systems,” explains the Rice University Stanley C. Moore Professor of Electrical and Computer Engineering, Naomi Halas. She is also the director of the Rice Laboratory for Nanophotonics. The UCSD group highlights details of their new lasers in the latest issue of the scientific journal Nature Photonics. They say that their laser can produce light with a wavelength of 1.43 microns at room temperature.