ABSTRACT
Once the wavefront is detected and the signals are appropriately configured, the wavefront corrector will alter the wavefront and complete the task of correcting the images or controlling a distorted beam. While the requirements for correcting atmospheric turbulence can be presented from theory, the implementation is subject to electro-mechanical constraints. In this chapter, various actuator types are presented including ferroelectrics, electrostatics, and magnetostrictives. Specifically, ferroelectrics and voice coils are discussed with their history of success in adaptive optics correctors. The actuators are applied to various optical configurations such as basic tip and tilt correction or modal higher-order correction. More importantly, deformable mirrors (DMs) are discussed, including segmented, surface-normal mirrors (discrete actuator continuous faceplate DMs), edge actuated mirrors, membrane and micro-machined mirrors, as well as bimorph, unimorph, and multimorph DMs. Large correcting optics such as telescope primary mirrors or adaptive telescope secondary mirrors have unique design requirements for their multiple optical tasks. Other correction devices are discussed in this chapter such as liquid crystal phase modulators, spatial light modulators, metasurfaces, fluidic DMs, and multiple active lens systems. The chapter concludes with a short discussion on the electronic drivers for the various wavefront correctors.
