Persistent Link:
http://hdl.handle.net/10150/184849
Title:
New technologies for polishing and testing large optics.
Author:
Wizinowich, Peter Lindsay
Issue Date:
1989
Publisher:
The University of Arizona.
Rights:
Copyright © 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.
Abstract:
Two new technologies, for polishing and testing large optics, are presented in this dissertation. The first is a new approach to generating and polishing aspheric surfaces which utilizes a full size stressed lap. The lap specifications are chosen to automatically generate a specific amount of spherical aberration. The required comatic distortion of the lap is induced by a system of levers and springs which are stretched and relaxed as the lap moves. A lap was constructed to grind and polish a 20cm glass blank. The resultant polished surface, in agreement with the predicted asphericity, has 28 microns of spherical aberration at its edge, appropriate for a F/2.0 convex paraboloid. The average radial profile has a residual peak-to-valley error of 200nm and an rms error of 60nm. This experiment serves as a first successful test of the stressed lap concept and as a demonstration of a new method for generating aspheric secondary mirrors. The second new technology is concerned with testing large optics where vibrations can be a serious problem. A modification to the usual phase shifting interferometry reduction algorithm permits measurements to be taken fast enough to essentially freeze out vibrations. Only two interferograms are needed with an exact phase relationship; and these can be recorded very rapidly on either side of the interline transfer of a standard CCD video camera, prior to charge transfer readout. The third required interferogram is a null. An analysis of potential phase errors was performed for this "2 + 1" algorithm. In the developed implementation, two frequencies, dν/ν≈10⁻⁸, are generated with orthogonal polarizations. A Pockels cell rapidly switches the frequency entering the interferometer, resulting in a phase shift over the long path difference of the interferometer. The two time critical interferograms are acquired with a 1ms separation resulting in a reduction in sensitivity to vibration of one to two orders of magnitude. Laboratory tests were performed to compare this "2 + 1" system with a commercial phase shifting package. Similar phase determination accuracies were found when vibrations were low. However, the "2 + 1" system also succeeded when vibrations were large enough to wash out video rate fringes.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Optical instruments -- Testing.; Grinding and polishing.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Optical Sciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Angel, J. Roger P.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleNew technologies for polishing and testing large optics.en_US
dc.creatorWizinowich, Peter Lindsayen_US
dc.contributor.authorWizinowich, Peter Lindsayen_US
dc.date.issued1989en_US
dc.publisherThe University of Arizona.en_US
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_US
dc.description.abstractTwo new technologies, for polishing and testing large optics, are presented in this dissertation. The first is a new approach to generating and polishing aspheric surfaces which utilizes a full size stressed lap. The lap specifications are chosen to automatically generate a specific amount of spherical aberration. The required comatic distortion of the lap is induced by a system of levers and springs which are stretched and relaxed as the lap moves. A lap was constructed to grind and polish a 20cm glass blank. The resultant polished surface, in agreement with the predicted asphericity, has 28 microns of spherical aberration at its edge, appropriate for a F/2.0 convex paraboloid. The average radial profile has a residual peak-to-valley error of 200nm and an rms error of 60nm. This experiment serves as a first successful test of the stressed lap concept and as a demonstration of a new method for generating aspheric secondary mirrors. The second new technology is concerned with testing large optics where vibrations can be a serious problem. A modification to the usual phase shifting interferometry reduction algorithm permits measurements to be taken fast enough to essentially freeze out vibrations. Only two interferograms are needed with an exact phase relationship; and these can be recorded very rapidly on either side of the interline transfer of a standard CCD video camera, prior to charge transfer readout. The third required interferogram is a null. An analysis of potential phase errors was performed for this "2 + 1" algorithm. In the developed implementation, two frequencies, dν/ν≈10⁻⁸, are generated with orthogonal polarizations. A Pockels cell rapidly switches the frequency entering the interferometer, resulting in a phase shift over the long path difference of the interferometer. The two time critical interferograms are acquired with a 1ms separation resulting in a reduction in sensitivity to vibration of one to two orders of magnitude. Laboratory tests were performed to compare this "2 + 1" system with a commercial phase shifting package. Similar phase determination accuracies were found when vibrations were low. However, the "2 + 1" system also succeeded when vibrations were large enough to wash out video rate fringes.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectOptical instruments -- Testing.en_US
dc.subjectGrinding and polishing.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineOptical Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorAngel, J. Roger P.en_US
dc.contributor.committeememberShannon, Robert R.en_US
dc.contributor.committeememberWyant, James C.en_US
dc.identifier.proquest9005730en_US
dc.identifier.oclc703280882en_US
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