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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Compensation of strong thermal lensing in advanced interferometric gravitational waves detectors

Degallaix, Jerome January 2006 (has links)
A network of laser interferometer gravitational waves detectors spread across the globe is currently running and steadily improving. After complex data analysis from the output signal of the present detectors, astrophysical results begin to emerge with upper limits on gravitational wave sources. So far, however no direct detection has been announced. To increase the sensitivity of current detectors, a second generation of interferometers is planned which will make gravitational wave astronomy a reality within one decade. The advanced generation of interferometers will represent a substantial upgrade from current detectors. Especially, very high optical power will circulate in the arm cavities in order to reduce by one order of magnitude the shot noise limited sensitivity in high frequency. However, the theoretical shot noise limit will only be achieved after implementation of complex thermal lensing compensation schemes. Thermal lensing is direct consequence of the residual optical absorption inside the substrate and coating of the test masses and could have tragic consequences for the functionality of the interferometer. The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) in collaboration with LIGO will run a series of high optical power tests to understand the characteristics and effects of thermal lensing. During these tests, techniques to compensate thermal lensing will be experimented. This thesis mainly focused on the first high optical power test in Gingin, Australia. The first test will consist of a Fabry Perot cavity with the sapphire substrate of the input mirror inside the cavity. Due to the high optical circulating power a strong convergent thermal lens will appear in the input mirror substrate. Because of the presence of the thermal lens inside the cavity, the size of the cavity waist will be reduced and the cavity circulating power will decrease. Simulations using higher order mode expansion and FFT propagation code were completed to estimate ways to compensate strong thermal lensing for the Gingin first test. The term `strong thermal lensing? is used because the thermal lens focal length is comparable to the design focal length of the optical components. The expected performance of a fused silica compensation plate is presented and advantages and limits of this method are discussed. Experimental results on small scale actuators which can potentially compensate thermal lensing are detailed. The knowledge gained from these experiments was valuable to design the real scale compensation plate which was used in the first Gingin test. This test was carried at the end of 2005. The thermal lens due to 1 kW of optical power circulating in the sapphire substrate was successfully compensated using a fused silica plate. Yet, thermal lensing compensation may only be required for room temperature advanced interferometer. Indeed, we showed that cooling the interferometer mirror to cryogenic temperature can eliminate the thermal lensing problem and also substantially decrease the mirror thermal noise.
172

Dynamics of the thermosphere over Mawson, Antarctica /

Wardill, P January 1988 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, Mawson Institute, 1989. / Includes bibliographical references (leaves 140-151).
173

High performance vibration isolation techniques for the AIGO gravitational wave detector /

Chin, Eu-Jeen. January 2007 (has links)
Thesis (Ph. D.)--University of Western Australia, 2007.
174

Signal processing techniques for optical fiber sensors using white light interferometry /

Bhatia, Vikram, January 1993 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 78-80). Also available via the Internet.
175

Extrinsic Fabry-Perot Interferometric hydrogen gas sensor /

Zeakes, Jason S., January 1994 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 86-87). Also available via the Internet.
176

A shipboard global positioning system carrier phase interferometric aircraft flight reference system

Wellons, William Lee. January 1994 (has links)
Thesis (M.S.)--Ohio University, November, 1994. / Title from PDF t.p.
177

Wavelet analysis with information theory applied to laser interferometric gravitational wave antennas /

Flenner, Arjuna, January 2003 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 134-139). Also available on the Internet.
178

Wavelet analysis with information theory applied to laser interferometric gravitational wave antennas

Flenner, Arjuna, January 2003 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 134-139). Also available on the Internet.
179

Tunable laser module for fibre optic communications /

Heikkinen, Veli. January 1900 (has links) (PDF)
Thesis (doctoral)--University of Oulu, 2004. / Includes bibliographical references (p. 147-171). Also available on the World Wide Web.
180

Application of a Fabry-Perot interferometer for measuring machining forces in turning operations /

Hansbrough, Andrew K., January 1993 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 77-79). Also available via the Internet.

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