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Proceedings Paper

Closed-loop control of magnetic fluid deformable mirrors
Author(s): Azhar Iqbal; Zhizheng Wu; Foued Ben Amara
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Paper Abstract

Adaptive optics (AO) systems make use of active optical elements, namely wavefront correctors (WFC), to improve the resolution of imaging systems by compensating for complex optical aberrations. Recently, magnetic fluid deformable mirrors (MFDM) were proposed as a promising new type of WFCs. These mirrors are developed by coating the free surface of a magnetic fluid with a thin reflective film of nano-particles. The reflective surface of the mirrors can be deformed using a locally applied magnetic field and thus serves as a WFC. MFDMs have been found particularly suitable for ophthalmic imaging systems where they can be used to compensate for the complex aberrations in the eye that blur the images of the internal parts of the eye. However, their practical implementation in clinical devices is hampered by the lack of effective methods to control the shape of their deformable surface. This paper presents a control algorithm that facilitated the first-ever use of a MFDM in a closed-loop AO system. The algorithm utilizes the influence function technique to decouple the multi-input multi-output system and features a proportional-integral controller structure. Experimental results showing the performance of the closed-loop system comprising the presented controller and a 19-channel prototype MFDM are presented.

Paper Details

Date Published: 4 August 2009
PDF: 9 pages
Proc. SPIE 7386, Photonics North 2009, 738628 (4 August 2009); doi: 10.1117/12.839872
Show Author Affiliations
Azhar Iqbal, Univ. of Toronto (Canada)
Zhizheng Wu, Univ. of Toronto (Canada)
Foued Ben Amara, Univ. of Toronto (Canada)

Published in SPIE Proceedings Vol. 7386:
Photonics North 2009
Réal Vallée, Editor(s)

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