American scientists carefully designed air waveguide, which repeatedly improves the laser beam propagation in the atmosphere Bashny.Net

The laser beam in the air, particularly if the power is high, quite limited because of interaction with the atmosphere. The laser heats the gas, which passes through, because of which the density varies, and hence the refractive index of air in the path. The atmosphere starts to work as a lens, diverging beam. Scientists from the University of Maryland, College Park придумали, how to overcome the negative consequences of this effect. To do this they have used several additional lasers arranged around the core.

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Auxiliary lasers give a short femtosecond flash before the main laser is activated. This flash heats the air around the path that goes main beam forming a fiber with the air pressure within the zone of high and low - around the perimeter. Thanks to this main beam is scattered much less. A similar principle is used in optical fiber - of its outer and inner layers have different refractive index, because of which the light is propagated with minimal losses never touching the walls of the fiber. The illustration shows the scheme of a fiber profile and photos using four and eight auxiliary laser

Effect of air fiber allow several orders to improve the signal-to-noise wherever the laser beam propagates in the atmosphere over long distances - in lidarh, communication systems, and laser spectroscopy, similar to what is installed on the rover Curiosity. In addition, the possible military applications of the research sponsors - the US Air Force and the Agency Defense Threat Reduction Agency (DTRA). As you know, in the past year have been successful tests laser gun , which is able to destroy the drones and the small boats of the enemy. In the future, these lasers could replace expensive rockets, but they do work only over short distances due to scattering of the beam.



Source: habrahabr.ru/post/231535/