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dc.contributor.advisorBurge, James H.en
dc.contributor.authorFrater, Eric
dc.creatorFrater, Ericen
dc.date.accessioned2016-11-30T20:42:58Z
dc.date.available2016-11-30T20:42:58Z
dc.date.issued2016
dc.identifier.urihttp://hdl.handle.net/10150/621452
dc.description.abstractThe growing field of high-order aspheric and freeform optical fabrication has inspired the creation of optical surfaces and systems which are difficult to align. Advances in optical alignment technology are critical to fabricating and integrating aspheric components in advanced optical systems. This dissertation explores the field of optical alignment with a computer-generated hologram (CGH) used as a reference. A CGH is a diffractive optic which may be used to create a desired phase profile across a beam of light, project irradiance patterns, or serve as a mask for an incident beam. The alignment methods presented in this dissertation are concerned with the use of a CGH to create reference phase profiles, or "wavefronts" , in a beam. In one application a set of axisymmetric CGH references are co-aligned. Each CGH has also been aligned to an aspheric mirror so the co-alignment of the CGH references is also a co-alignment of the aspheric mirrors. Another application is concerned with aligning an interferometer to test an aspheric mirror surface. The interferometer measures a "null" interference pattern when its wavefront accommodates a known surface profile. In this alignment application the CGH creates wavefronts which accommodate a known set of small spherical reference features at the test surface. An interference null from all the "phase fiducial" reference features indicates an aligned projection of the CGH. The CGH co-alignment method is implemented on a 4-mirror prime focus corrector known as the Hobby-Eberly Telescope Wide Field Corrector (HET WFC). It is shown that this method was very successful for centration alignment of some mirrors, whereas mechanical stability was the hardware limitation for other degrees of freedom. The additional alignment methods used in this project are described in detail and the expected alignment of the HET WFC is reported.The fabrication, characterization and application of spherical phase fiducials is demonstrated in a CGH-corrected Fizeau test prototype. It is shown that these reference features achieve <±1.5µm transverse alignment precision. A pair of phase fiducials is also applied to constrain the clocking and magnification of a projected wavefront. Fabrication and coordinate measurement of the features present the dominant challenges in these demonstrations.
dc.language.isoen_USen
dc.publisherThe University of Arizona.en
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en
dc.subjectCGHen
dc.subjectFiducialsen
dc.subjectInterferometeren
dc.subjectInterferometryen
dc.subjectPhaseen
dc.subjectOptical Sciencesen
dc.subjectAlignmenten
dc.titleOptical Alignment with CGH Phase Referencesen_US
dc.typetexten
dc.typeElectronic Dissertationen
thesis.degree.grantorUniversity of Arizonaen
thesis.degree.leveldoctoralen
dc.contributor.committeememberBurge, James Hen
dc.contributor.committeememberKim, Dae Wooken
dc.contributor.committeememberSasián, José M.en
thesis.degree.disciplineGraduate Collegeen
thesis.degree.disciplineOptical Sciencesen
thesis.degree.namePh.D.en
refterms.dateFOA2018-09-11T15:54:11Z
html.description.abstractThe growing field of high-order aspheric and freeform optical fabrication has inspired the creation of optical surfaces and systems which are difficult to align. Advances in optical alignment technology are critical to fabricating and integrating aspheric components in advanced optical systems. This dissertation explores the field of optical alignment with a computer-generated hologram (CGH) used as a reference. A CGH is a diffractive optic which may be used to create a desired phase profile across a beam of light, project irradiance patterns, or serve as a mask for an incident beam. The alignment methods presented in this dissertation are concerned with the use of a CGH to create reference phase profiles, or "wavefronts" , in a beam. In one application a set of axisymmetric CGH references are co-aligned. Each CGH has also been aligned to an aspheric mirror so the co-alignment of the CGH references is also a co-alignment of the aspheric mirrors. Another application is concerned with aligning an interferometer to test an aspheric mirror surface. The interferometer measures a "null" interference pattern when its wavefront accommodates a known surface profile. In this alignment application the CGH creates wavefronts which accommodate a known set of small spherical reference features at the test surface. An interference null from all the "phase fiducial" reference features indicates an aligned projection of the CGH. The CGH co-alignment method is implemented on a 4-mirror prime focus corrector known as the Hobby-Eberly Telescope Wide Field Corrector (HET WFC). It is shown that this method was very successful for centration alignment of some mirrors, whereas mechanical stability was the hardware limitation for other degrees of freedom. The additional alignment methods used in this project are described in detail and the expected alignment of the HET WFC is reported.The fabrication, characterization and application of spherical phase fiducials is demonstrated in a CGH-corrected Fizeau test prototype. It is shown that these reference features achieve <±1.5µm transverse alignment precision. A pair of phase fiducials is also applied to constrain the clocking and magnification of a projected wavefront. Fabrication and coordinate measurement of the features present the dominant challenges in these demonstrations.


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