Detecting dangerous chemicals with lasers, exploring the brain's circuitry with light and more

Lead researcher Michael Moewe says that, in addition to optoelectronic devices, he expects the needles to be valuable in such applications as atomic force microscopy (AFM), where the sharp tips can be grown in arrays without further etching or processing steps. Some believe that AFM arrays, besides speeding up the recording of nearly atomic-resolution images of surfaces (allowing one to create atomic movies), might be used to create a new form of data storage by influencing the atoms in the sample. The needles also may be used in producing tip-enhanced Raman spectroscopy. Raman spectroscopy is a process in which the energy levels of molecules are determined by shining light at a known frequency into the sample and then observing the frequency of the outgoing light. Delivering light from a sharp tip allows a much more targeted examination of the sample, possibly even permitting the spectroscopic study of single molecules. (Talk CTuCC1, "Bright Photoluminescence from GaAs and InGaAs Nanoneedles Grown on Si Substrates.")

NATIONAL IGNITION FACILITY—THE WORLD'S LARGEST LASER SYSTEM

The National Ignition Facility at Lawrence Livermore National Laboratory (LLNL), a project more than a decade in the making, is scheduled for completion in March 2009. When it goes online, 192 laser beams will generate millions of joules of infrared light, which will in turn be converted to ultraviolet light just prior to reaching the focus of these lasers. Electro-optical devices will time, shape, and direct this light. In a facility the size of three football fields, the light will go through a tiny hole into a target made of gold and uranium. This target has the shape of a soda can, but is less than one inch in height. There the light will paint the inside walls of this chamber, heating the metal walls and causing them to emit X-rays that will fill the can, bombard a small plastic capsule in the can's center, implode the capsule, and trigger the fusion of tritium and deuterium inside.

Lead researcher Christopher A. Haynam with LLNL will focus on the status of the light that will drive this operation—by far the largest laser system in the world. So far, about three quarters of the lasers have been installed. These lasers have been operated to more than 3.1 million joules total energy in the infrared. A few beams have been pointed to a target, and a number of low-energy shots taken and converted to the ultraviolet to check their alignment. If it works as it is supposed to, the National Ignition Facility will be able to achieve temperatures and pressures that emulate conditions in the interior of planets or stars. (Talk CFQ1, "The National Ignition Facility: Status and Performance of the World’s Largest Laser System for the High Energy Density and Inertial Confinement Fusion.")