Technology and applications of micromachined adaptive mirrors

Publisher Website
Google Scholar
Abstract
The end of the cold war and the introduction of military technologies to the market has created new application fields for many originally military technologies. One of these technologies is adaptive optics, dealing with dynamic control of the quality of an optical system. As for almost any technology `imported' from the military research field, adaptive optics is expensive. Fortunately there are many civil applications for adaptive optics which produce the necessary development thrust. Expensive adaptive optics are acceptable for applications where specialized custom-made systems are needed. In the past, and even now, designers of large ground-based telescopes costing in excess of tens of millions of dollars could afford expensive, specially designed high-quality adaptive systems to improve image quality. The extension of adaptive optics into the field of less expensive scientific equipment such as low-end professional telescopes, industrial lasers and optical information processing systems will only be possible after reduction of the fabrication costs by a few orders of magnitude. The functionality and quality of devices and systems must be preserved or even improved during the transition described. The market sector for serially-produced scientific equipment, industrial laser systems and components, information processing equipment such as CD player optical pickups, amateur telescopes, optical communication systems and displays is comparable to the aforementioned high-end military and scientific sectors. To deal with the large volume demand, serial or even mass-production technologies should be used for the fabrication of adaptive optics. The problem of high system quality at low cost can be solved using silicon micromachining. Various optical micromachined devices have been demonstrated in the past twenty years, among them micromachined adaptive mirrors. Silicon-based microfabrication in its present state forms the technological foundation for inexpensive implementation of complete adaptive optical systems, as it allows for cheap fabrication of CCD-based wavefront sensors, control computers and wavefront correctors in the framework of a uniformly inexpensive technology.