Segmented silicon-micromachined microelectromechanical deformablemirrors for adaptive optics

摘要

Deformable mirrors improve optical efficiency of a system byncorrecting the wave front aberration caused by imperfections in thensystem components or by turbulent atmosphere in case of telescopenoptics. Micromachined mirror technology has the potential tonsubstantially reduce the cost of adaptive optics systems. First, a briefnreview of the work in this field is presented with the goal of informingnthe reader of the challenges in the micromachined adaptive optics andnthe implementation tradeoffs including stress-induced curvature ofnmultilayer mirrors. Then, recent results on the silicon micromachined,nhybrid integrated microelectromechanical deformable mirrors for adaptivenoptics developed at the University of Colorado are presented. Variousnmicrofabrication processes including surface micromachining, bulknmicromachining, and flip-chip assembly are implemented to fabricate highnoptical fill factor and large-stroke piston-type micromirror arrays. Thenachieved micromirror deflection for some designs is in the range of 2 ton3.5 Μm, which results in the operating wavelength within infrarednspectrum. Techniques to integrate microlenses on top of the micromirrorsnusing self-aligned solder or transfer of ultrasmooth mirror plates onntop of the micromirror actuators using flip-chip create high opticalnfill factor devices. Experimental results of aberration correction withnsuch devices are presented