Laser researchers boldly go into uncharted THz territory
Once the preferred weapon of B-movie madmen and space-fiction heroes alike, the laser—a device that generates an intense beam of coherent electromagnetic radiation by stimulating the emission of photons from excited atoms or molecules—has grown a bit domesticated of late.
These days, it has a steady job in industry, and spends its spare time printing documents in home offices and playing back movies in home theaters. Here and there it pops up in medical journals and military news, but it's basically been reduced to reading barcodes at the grocery checkout—a technology that's lost its mojo. But lasers are still cool, insists Sushil Kumar of Lehigh University, with vast potential for innovation we've just begun to tap. And with support from the National Science Foundation (NSF), he's on a mission to prove it.
Kumar, an associate professor of electrical and computer engineering, focuses specifically on lasers that arise from a relatively unexploited region in the electromagnetic spectrum, the terahertz (THz), or far infrared, frequency. A researcher at the forefront of THz semiconductor 'quantum-cascade' laser technology, he and his colleagues have posted world-record results for high-temperature operation and other important performance characteristics of such lasers.
