Optical Beam Control

Chapter 6Adaptive Optics

6.1 Introduction

Adaptive optics (AO) is a rapidly growing multidisciplinary field encompassing physics, chemistry, electronics, and computer science. AO systems are used to correct the wavefront of a beam of light. Historically, these systems have their roots in international astronomy and US defense communities. Astronomers realized that if they could compensate for the aberrations caused by atmospheric turbulence, they would be able to generate high-resolution astronomical images; with sharper images comes an additional gain in contrast, which is also advantageous for astronomers since it means that they can detect fainter objects that would otherwise go unnoticed. While astronomers were trying to overcome the blurring effects of atmospheric turbulence, defense contractors were interested in ensuring that photons from their high-power lasers would be correctly pointed so as to destroy strategic targets. More recently, due to advancements in the sophistication and simplicity of AO components, researchers have utilized these systems to make breakthroughs in areas such as microscopy, laser communication, vision correction, and retinal imaging.

AO, as the name implies, adjusts the optical elements, such as mirror shape, in real time to counteract distortions in light wavefront caused by such atmospheric turbulence and in imaging satellites due to imperfection in the shape of the primary mirror. AO has three main components: wavefront sensor, control ...