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Dissertation/Thesis Abstract

Use of computer generated holograms for optical alignment
by Zehnder, Rene, Ph.D., The University of Arizona, 2011, 333; 3450778
Abstract (Summary)

The necessity to align a multi component null corrector that is used to test the 8.4 [m] off axis parabola segments of the primary mirror of the Giant Magellan Telescope (GMT) initiated this work. Computer Generated Holograms (CGHs) are often a component of these null correctors and their capability to have multiple functionality allows them not only to contribute to the measurement wavefront but also support the alignment. The CGH can also be used as an external tool to support the alignment of complex optical systems, although, for the applications shown in this work, the CGH is always a component of the optical system.

In general CGHs change the shape of the illuminating wavefront that then can produce optical references. The uncertainty of position of those references not only depends on the uncertainty of position of the CGH with respect to the illuminating wavefront but also on the uncertainty on the shape of the illuminating wavefront. A complete analysis of the uncertainty on the position of the projected references therefore includes the illuminating optical system, that is typically an interferometer. This work provides the relationships needed to calculate the combined propagation of uncertainties on the projected optical references. This includes a geometrical optical description how light carries information of position and how diffraction may alter it.

Any optical reference must be transferred to a mechanically tangible quantity for the alignment. The process to obtain the position of spheres relative to the CGH pattern where, the spheres are attached to the CGH, is provided and applied to the GMT null corrector. Knowing the location of the spheres relative to the CGH pattern is equivalent to know the location of the spheres with respect to the wavefront the pattern generates.

This work provides various tools for the design and analysis to use CGHs for optical alignment including the statistical foundation that goes with it.

Indexing (document details)
Advisor: Martin, Hubert
Commitee: Dallas, William, Sasian, Jose
School: The University of Arizona
Department: Optical Sciences
School Location: United States -- Arizona
Source: DAI-B 72/07, Dissertation Abstracts International
Subjects: Optics
Keywords: Computer generated holograms, Interferometer, Maximum likelihood estimation, Optical alignment
Publication Number: 3450778
ISBN: 978-1-124-59913-7
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