Researchers at the University of Michigan in Ann Arbor have reported continuous-wave 404.1-, 408.1- and 409.6-nm laser emission at room temperature from an electrically pumped nanocrystalline powder of Nd:Al₂O₃. The powder, which they described in the March 15 issue of Optics Letters, promises applications in lighting, chemical sensing, lithography and displays.

Because the nanocrystal powder strongly scatters incident light, the researchers opted to use electrical rather than optical pumping in the experiments, employing a focused beam of 2- to 10-keV electrons. They propose that laser action in the medium is the result of strong multiple scattering.