LLNL scientists build nonlinear laser

17 Jun 2002

Scientists at Los Alamos National Laboratory have developed a new form of laser light travel that could create important new laser-based technologies and revolutionize some older ones. A team of researchers experimenting with a powerful infrared titanium-sapphire laser found that when a light pulse intensity reaches a critical value, the beam focuses itself into a thin filament without the aid of focusing lenses or mirrors and perpetuates itself for long distances.

The beam -- two to three times the thickness of a human hair -- propagates virtually indefinitely through air without spreading, something conventional lasers cannot do. In a very simplistic way, the new discovery is similar to a flashlight that shines for an indefinite distance without a focusing, parabolic mirror behind the bulb; beams from both flashlights and ordinary lasers fan out as the light gets farther from the source. Researchers believe that the intense laser light self-compensates and becomes trapped in three dimensions. Because of the intensity of the beam, nonlinear effects compensate for each other giving the appearance that there is no dispersion, diffraction or scattering.