This work describes a new class of flexible optical materials that can be dynamically shaped in a magnetic field. The materials are a combination of a superparamegnetic colloid known as a ferrofluid, coated with a Metal Liquid-Like Film (MELLF) to provide a reflective surface. Without the mechanical constraints of solid optical surfaces, liquid mirrors offer greatly improved stroke. The ease of fabrication of liquid optical surfaces also offers the potential for substantial cost savings over traditional materials. I begin by presenting an overview of current deformable mirror technology used in adaptive optics and then describe the underlying magnetic and hydrodynamic theory of magnetic liquid mirrors. The design and testing of a prototype deformable mirror is discussed in detail and simulations of the mirror shape under various conditions are presented. A variety of magnetic fluids were characterized to determine response time and maximum deformation. Strokes in excess of 20 mu m were demonstrated at frequencies up to 10 Hz with no measurable actuator hysteresis. The reflectivity of coated ferrofluids was measured to determine temporal and spatial variations. Coated ferrofluids were found to have stable reflectivity for periods of 14 days and deposition techniques being developed by chemists at Universite Laval show considerable promise to extend this duration. Preliminary experimental results and simulations of wavefront control are presented. The suitability of magnetic liquid mirrors for a number of adaptive optics applications is discussed in terms of the experimental results with the prototype mirror described earlier. Finally, a number of methods to improve the performance of magnetic liquid mirrors are proposed.
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