The department of Atmospheric Propagation and Effect focuses on laser applications in the open atmosphere. Main topics are the use of laser radiation over long distances such as optical energy transmission (laser power beaming, laser-based air defence) and the remote detection of pollutants and hazardous substances. Atmospheric applications of laser radiation require precise knowledge of the weather and the predictability of the influence of atmospheric factors on the radiation field. Air turbulence can lead to deflection of a laser beam, changes to the intensity profile, for example, and the deterioration of the beam quality. Aerosols in the air cause radiation scattering and must therefore be taken into account from the point of view of eye protection against laser radiation. These effects are studied by the Institute of Technical Physics at the DLR optical test range at Lampoldshausen. The Atmospheric Propagation and Effect department thus combines expertise with regard to beam propagation, along with numerical simulation, with applications from the DLR cross-discipline topic of security.