File:Starfield Optical Range - sodium laser.jpg

Original caption: "This sodium laser—being fired from the Starfire Optical Range on Kirtland Air Force Base, New Mexico—is used with deformable optics to help eliminate atmospheric distortions when gathering images of objects in space."

Though the caption states that this is a "sodium laser", this is actually misleading as the Starfire Optical Range LIDAR laser seen here is actually two solid state IR lasers, 1.064 and 1.319 microns, that are frequency summed in LBO within a doubly resonant cavity. The orange beam is observed due to the intense laser light scattering off particles in the air. In general, laser light travelling through a vaccum can not be seen unless aimed directly towards the observer.

License

 * Source: Directed Energy Directorate, US Air Force