A Laser in Tune with Itself; February 1999; Scientific American Magazine; by Beardsley; 2 Page(s)

From the original home of the laser comes news of a variant with a unique feature: it emits light at three different infrared wavelengths simultaneously. The device, though still definitely a laboratory curiosity, could in principle be adapted for use in sensors that monitor the concentration of trace chemicals in the atmosphere or in other gases or liquids. But it is perhaps more remarkable as an indication of progress in quantum engineering.

Federico Capasso and his group at Bell Laboratories built the new device. (Bell Labs, now owned by Lucent Technologies, was part of AT&T when Arthur L. Schawlow and Charles H. Townes worked there in 1958 and first described the concept of the laser.) Capasso's invention is a semiconductor laser, though not of the low-power type now widely used in communications. Rather it is a variant of the quantum cascade laser, which Capasso, along with Jerome Faist, now at the University of Neuchatel in Switzerland, invented only in 1994. Capasso and Faist won the 1998 IEEE Lasers and Electro-Optics Society William Streifer award for that breakthrough.