Freezing Light in Its Tracks

摘要

Light is thought to be the fastest stuff around, zipping so speedily through the universe that, even if it were tangible, you probably couldn't pin it down. But in September, physicists reported the seemingly impossible: They froze light into a crystal-like state. Light particles, or photons, normally interact only with matter, not each other. But Princeton physicist Andrew Houck and colleagues built a device that effectively lets one photon trade energy with another, putting them in a crystal-like state. The device, about 1/4 inch across, sounds simple: two tiny wires bridged at one end by a capacitor, with the other ends plugged into photon generators. The team first shot photons into the wires while blocking their exit with two-way mirrors, and the photons behaved normally, bouncing freely back and forth between the wires.