title: A magnetic liquid deformable mirror for high stroke and low order axially symmetrical aberrations.
abstract: We present a new class of magnetically shaped deformable liquid mirrors made of a magnetic liquid (ferrofluid). Deformable liquid mirrors offer advantages with respect to deformable solid mirrors: large deformations, low costs and the possibility of very large mirrors with added aberration control. They have some disadvantages (e.g. slower response time). We made and tested a deformable mirror, producing axially symmetrical wavefront aberrations by applying electric currents to 5 concentric coils made of copper wire wound on aluminum cylinders. Each of these coils generates a magnetic field which combines to deform the surface of a ferrofluid to the desired shape. We have carried out laboratory tests on a 5 cm diameter prototype mirror and demonstrated defocus as well as Seidel and Zernike spherical aberrations having amplitudes up to 20 microm, which was the limiting measurable amplitude of our equipment.
authors.forename: Denis
authors.initials: D
authors.lastname: Brousseau
authors.forename: Ermanno F
authors.initials: EF
authors.lastname: Borra
authors.forename: Hubert
authors.initials: H
authors.lastname: Jean-Ruel
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Parent
authors.forename: Anna
authors.initials: A
authors.lastname: Ritcey