To make a laser filament last longer, a team of American physicists decided to shine it inside another, less intense beam of light, which they called a dressing beam. The dressing beam feeds energy into the filament so it can stretch farther. In an experiment, the American team showed an optical filament accompanied by a dressing beam stretches about 7.2 feet. Without the dressing beam, the filament was only about eight inches long. Other teams have been able to extend optical filaments to twice their original lengths, the team wrote in a paper they published in the journal Nature Photonics, while this effort stretched an optical filament by 11 times its original length.