Membrane-based deformable mirror: intrinsic aberrations and alignment issues

Bayanna, Raja A and Louis, Rohan E and Chatterjee, S and Mathew, Shibu K and Venkatakrishnan, P (2015) Membrane-based deformable mirror: intrinsic aberrations and alignment issues. In: APPLIED OPTICS, 54 (7). pp. 1727-1736. (In Press)

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Abstract

A deformable mirror (DM) is an important component of an adaptive optics system. It is known that an on-axis spherical/parabolic optical component, placed at an angle to the incident beam introduces defocus as well as astigmatism in the image plane. Although the former can be compensated by changing the focal plane position, the latter cannot be removed by mere optical realignment. Since the DM is to be used to compensate a turbulence-induced curvature term in addition to other aberrations, it is necessary to determine the aberrations induced by such (curved DM surface) an optical element when placed at an angle (other than 0 deg) of incidence in the optical path. To this effect, we estimate to a first order the aberrations introduced by a DM as a function of the incidence angle and deformation of the DM surface. We record images using a simple setup in which the incident beam is reflected by a 37 channel micro-machined membrane deformable mirror for various angles of incidence. It is observed that astigmatism is a dominant aberration, which was determined by measuring the difference between the tangential and sagittal focal planes. We justify our results on the basis of theoretical simulations and discuss the feasibility of using such a system for adaptive optics considering a trade-off between wavefront correction and astigmatism due to deformation. (C) 2015 Optical Society of America

Item Type:	Journal Article
Publication:	APPLIED OPTICS
Publisher:	OPTICAL SOC AMER
Additional Information:	Copy right for this article belongs to the OPTICAL SOC AMER, 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA
Keywords:	ADAPTIVE OPTICS SYSTEM
Department/Centre:	Division of Electrical Sciences > Computer Science & Automation
Date Deposited:	20 Apr 2015 11:13
Last Modified:	20 Apr 2015 11:13
URI:	http://eprints.iisc.ac.in/id/eprint/51289

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