A small laser could be the key to increasing the amount of data storage on compact disks if Peidong Yang, a professor of chemistry at the University of California in Berkeley, has his way. His laser, which is one thousand times thinner than a human hair, is also said to be an alternative to today’s solid state lasers made from gallium arsenide and gallium nitride. Instead, Yang uses zinc oxide. He paints a gold catalyst onto a sapphire and places it in zinc oxide. The gold forms the crystal wires, which are hexagonal in cross section. The arrays of wire resemble hairbrush bristles. They emit UV light from their flat tips, which act like mirrors. The ends attached to the semiconductor also act like mirrors. Light emitted by the zinc oxide bounces back and forth, causing emission and amplification of the light. Yang uses optical pumping for exciting the zinc-oxide molecules. “Optical pumping uses a conventional laser for exciting our nanowire sample, so that stimulated emission can be generated from the nanowires,” explains Yang. “One of the next steps in commercializing the nanolaser is its successful integration as a miniaturized light source in optoelectronic applications,” he says. For more information, contact Yang at (510) 643-1545 or go to www.cchem.berkeley.edu.
Fifty-six-year-old Pasquale Russo has been doing metalwork for more than 30 years in a tiny southern Italy village. Many craftsmen like him brought with them fabrication skills when they came from the Old World to America.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.