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Proceedings Paper

Low-cost deformable mirror for laser focussing
Author(s): W. Greger; T. Hösel; T. Fellner; A. Schoth; C. Mueller; J. Wilde; H. Reinecke
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Paper Abstract

This paper presents a new concept of low degree-of-freedom deformable mirrors. The application of the mirror is the focusing of a laser beam, featuring a variable focal length. The deformation shape, which is in this case a circular parabolic and an elliptical parabolic respectively, is achieved by a local variation of the mirror's thickness. The paper explains the analytical treating of the mirror's thickness distribution as well as an iterative approximation procedure using FEM simulation. The mirrors were fabricated using hot embossing and injection molding technology. The molds required are made from steel whereas the structuring is done by conventional milling. The fabricated mirrors were coated with a reflective gold layer. For deformation measurements a functional demonstrator consisting of the coated mirror, assembly plates and an electromagnetic actuator was produced. The deformation of the mirror was measured using a 3D coordinate measuring machine. The optical function was characterized by a CCD laser measurement setup. Deviation between the measured and the optimal deformation function was sufficiently small. The spot size of the focused laser beam was up to 470 μm whereas the focal length could be varied in a range of 250 mm to 1000 mm. Due to the use of polymeric material, the long time behavior in respect of creep was researched using FEM simulations as well as endurance tests.

Paper Details

Date Published: 19 October 2006
PDF: 11 pages
Proc. SPIE 6374, Optomechatronic Actuators, Manipulation, and Systems Control, 63740F (19 October 2006); doi: 10.1117/12.685206
Show Author Affiliations
W. Greger, Univ. of Freiburg, IMTEK (Germany)
T. Hösel, Univ. of Freiburg, IMTEK (Germany)
T. Fellner, Univ. of Freiburg, IMTEK (Germany)
A. Schoth, Univ. of Freiburg, IMTEK (Germany)
C. Mueller, Univ. of Freiburg, IMTEK (Germany)
J. Wilde, Univ. of Freiburg, IMTEK (Germany)
H. Reinecke, Univ. of Freiburg, IMTEK (Germany)


Published in SPIE Proceedings Vol. 6374:
Optomechatronic Actuators, Manipulation, and Systems Control
Farrokh Janabi-Sharifi; Yukitoshi Otani, Editor(s)

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