Thresholdless Nanoscale Coaxial Lasers
Researchers at the University of California at San Diego successfully made a thresholdless nanoscale laser, meaning it funneled all its photons into the beam and wasted none of the energy needed to generate a laser at such a small scale. The device also was the smallest room-temperature, continuous-wave laser to operate at telecommunications frequencies. The work was conducted as part of an NSF-funded Engineering Research Center (ERC), the Center for Integrated Access Networks (CIAN) based at the University of Arizona. It was reported in the February 8, 2012 issue of the journal Nature.
The discovery of this continuous-wave coaxial laser is crucial to developing low-energy optical networks on computer chips. Such lasers will be able to send and receive optical signals powered only by the minuscule amounts of energy available in semiconductors.
Because of their small size and lack of threshold, or energy lost as they reach the point of lasing, these devices can be modulated much quicker than existing lasers and generate coherent emission at infinitely low energies. They can become a backbone for future communication devices on a chip.
The research team achieved its breakthrough by fashioning a family of nanostructured cavities that potentially solve the scalability challenge by means of their geometry and metal composition.