Beam control for high-energy laser devices

Abstract. Beam-control systems for high-average-power lasers began in the late 1960s and early 1970s. Early systems propagated the beams across laboratories using heavy-water-cooled copper optics and open-beam trains with commercial fans to provide fresh air. They have evolved in the intervening 40-plus years to include highly sophisticated gimbaled-control systems with extremely high-reflectance uncooled optics and adaptive optics to compensate for less-than-ideal laser beams and for atmospheric distortions. An overview of that evolution is presented.