Technology and applications of micromachined adaptive mirrors

The end of the cold war and the introduction of military technologies to th e market has created new application fields for many originally military te chnologies. One of these technologies is adaptive optics, dealing with dyna mic control of the quality of an optical system. As for almost any technolo gy 'imported' from the military research held, adaptive optics is expensive . Fortunately there are many civil applications for adaptive optics which p roduce 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 la rge ground-based telescopes costing in excess of tens of millions of dollar s could afford expensive, specially designed high-quality adaptive systems to improve image quality. The extension of adaptive optics into the field o f less expensive scientific equipment such as low-end professional telescop es, industrial lasers and optical information processing systems will only be possible after reduction of the fabrication costs by a few orders of mag nitude. The functionality and quality of devices and systems must be preser ved or even improved during the transition described. The market sector for serially-produced scientific equipment, industrial la ser systems and components, information processing equipment such as CD pla yer optical pickups, amateur telescopes, optical communication systems and displays is comparable to the aforementioned high-end military and scientif ic sectors. To deal with the large volume demand, serial or even mass-produ ction technologies should be used for the fabrication of adaptive optics. T he problem of high system quality at low cost can be solved using silicon m icromachining. Various optical micromachined devices have been demonstrated in the past tw enty years, among them micromachined adaptive mirrors. Silicon-based microf abrication in its present state Forms the technological foundation for inex pensive implementation of complete adaptive optical systems, as it allows f or cheap fabrication of CCD-based wavefront sensors, control computers and wavefront correctors in the framework of a uniformly inexpensive technology .