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Radiation-induced desorption and surface modification in dielectric single crystal materialsKjelgaard, Khin, January 2004 (has links) (PDF)
Thesis (Ph. D.)--Washington State University. / Includes bibliographical references.
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Control & manipulation of femtoliter droplets for the study of single cell reactions & nanochemistry /Jeffries, Gavin D. M. January 2008 (has links)
Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (leaves 125-142).
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Tunable liquid crystal polarization gratingsShi, Lei, January 2009 (has links)
Thesis (Ph.D.)--Kent State University, 2009. / Title from PDF t.p. (viewed Apr. 22, 2010). Advisor: Philip Bos. Keywords: Liquid crystal; beam steering; polarization gratings; diffraction efficiency; decentered microlens array. Includes bibliographical references (p. 216-219).
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Frequency Domain Holography of laser wakefieldsMatlis, Nicholas Hill, January 1900 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.
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Interaction of intense laser fields with carbon nanotubesHsu, Han, January 1900 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.
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Measuring and modeling forces and micromechanical properties in laser traps /Knöner, Gregor. January 2006 (has links) (PDF)
Thesis (Ph.D.) - University of Queensland, 2006. / Includes bibliography.
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Correlations between the standard and alternative definitions of the beam quality factorStrauss, Hencharl Johan 04 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: The beam quality factor (M2) of a laser is important because it describes both the quality of a laser
beam as well as its propagation. Particular applications require that the beam radii (from which the
M2 factor is determined) be defined in a specific way. The International Standards Organisation
(ISO) recently standardised the theoretically correct, but practically difficult second moment
definition of the beam radius.
This thesis aims to establish correlations between the second moment definition and other more
practical definitions. Chapter 2 presents a systematic introduction of moment theory for general
beams. Beam centre and radius definitions as well as beam classification are derived by means of
second and mixed moments. In Chapter 3 simple laser beams are modelled by means of a resonator
approach. The infinite number of solutions of this model is called Gaussian solutions, which are
found to be different for rectangular and cylindrical symmetric resonators. The zero order solution
for both symmetries is identified as the ideal solution to which all others can be compared to for
quality determinations. Chapter 4 presents different beam scanning devices, beam radius definitions
and correlations between these definitions. The theoretical basis for a new correlation theory is also
given. Chapter 5 describes programs and computations used to verify existing correlation methods
and to calculate correlation factors for a newly proposed theory. Chapter 6 presents the results of the
computations for both circular and rectangular symmetric beams. The ISO’s correlation theories are
tested first. Newly proposed correlation functions between the second moment and alternative
definitions as well as theoretical error graphs are given for various beams. A novel method to
correlate several important beam subclasses is also presented. Chapter 7 describes the experimental
setup, automation software and post processing techniques that were used to characterise a modified
CO2 TEA laser. It is further shown how the theory developed in previous chapters could be applied
to the experimental data. Chapter 8 presents the experimental results of the beam characterisation
measurements performed on two different beams that emanated from the CO2 TEA laser. Existing
and newly developed correlation theories are applied to the experimental data and the corresponding
results are compared. In Chapter 9, conclusions and suggestions with respect to the initial aims
identified in the first chapter are made. Several suggestions for future work are also made. / AFRIKAANSE OPSOMMING: Die bundel kwalitietsfaktor (M2) is baie belangrik omdat dit beide die kwaliteit en
voortplanting van ‘n laser bundel beskryf. Bundel radiusse (waarvan die M2 faktor bepaal
word) word verskillend gedefinieer vir spesifike toepassings. Die teoreties korrekte, maar
minder praktiese tweede moment definisie is onlangs deur die Internasionale Standaard
Organisasie (ISO) gestandariseer.
Hierdie tesis se hoofdoel is om die tweede moment definisie en ander meer praktiese
definisies te korreleer. Hoofstuk 2 stel die moment teorie van bundels sistematies bekend.
Dit word gewys hoe die senter en radius van ‘n bundel deur tweede en gemengde
momente gedefinieer kan word. In Hoofstuk 3 word laser bundels gemodeleer deur
middel van resonator aanslag. Die oneindige aantal oplossings wat verkry word heet
Gaussiese oplossings en is verskillend vir reghoekige en silindriese simmetriese
resonators. Dit word gewys dat die ideale bundel, waarmee alle ander bundels vergelyk
word, die zero orde oplossing van beide simmetrieë is. Hoofstuk 4 stel verskillende
bundel skanderings apparaat, bundel radius definisies en korrelasies tussen die definisies
bekend. Die teoretiese basis vir ‘n nuwe korrelasie teorie word ook gegee. Hoofstuk 5
beskryf die rekenaarprogramme en berekeninge wat gebruik word om huidige korrelasie
teorie mee te toets asook om nuwes mee te skep. Hooftuk 6 gee die resultate van die
berekeninge van die rekenaarprogramme vir beide reghoekig en silindriese simmetrie.
Die ISO se korrelasies word eerste getoets voordat nuwe teorieë bekend gestel word. In
Hoofstuk 7 word die eksperimentele opstelling, outomisasie sagteware en postprosessering
tegnieke gewys wat gebruik was om ‘n aangepaste CO2 TEA laser te
karakteriseer. Verder word dit gewys hoe die teorie wat in voorafgaande hoofstukke
ontwikkel is op eksperimentele data toegepas kan word. Hoofstuk 8 gee die
eksperimentele resultate van die bundel karakterisering van twee verskillende bundels
vanaf die CO2 TEA laser. Bestaande en nuwe korrelasie metodes word gebruik om die
bundels te korreleer en die resultate van elke metode word dan met mekaar vergelyk. In
Hoostuk 9 word afleidings gemaak. Daar word ook voorstelle gemaak vir potensiële
toekomstige werk.
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Novel laser beams for optical trapping and tweezing.Ismail, Yaseera. January 2011 (has links)
Optical trapping and tweezing has been around for the last 30 years and since found its place in the
fields of physics and biology. Over the years this technique has advanced exceedingly and is a
unique tool to carry out research in the micrometre and nanometre scale regime. The aim of this
dissertation was to illustrate that an optical trapping and tweezing system is an effective tool for the
manipulation of micron sized particles and that using such a system allows one the ability to
accurately and precisely measure optical forces in the piconewton scale. A custom built single
gradient optical trapping system was built to illustrate the manipulation of micron sized particles.
Here we will highlight some of the key components of such a system and give an explanation of
how these components affect the optical trap. To enhance this system, we exploit the ability to
shape light and in particular laser light to generate novel laser beams. This was achieved using a
diffractive optical element known as a spatial light modulator (SLM).
A spatial light modulator is an electronically addressed optical element which when incorporated
into an optical system effectively manipulates the phase of light in order to generate various novel
laser beams. In particular these novel laser beams include Laguerre-Gaussian, Bessel and recently
proposed Bessel-like beams. Each of these beams contains interesting properties which can be
beneficially exploited. Laguerre-Gaussian beams are particularly known as ‘donut’ shaped beams
since they have a central dark hole. Increasing the order of these Laguerre-Gaussian beams leads to
an increase in the central dark region. These beams are of particular interest since they carry orbital
angular momentum. This is not easily observed; however, when incorporated into the optical
trapping system, leads to the rotation of trapped particles due to the transfer of photons carrying
orbital angular momentum. Bessel and Bessel-like beams on the other hand are classes of beam that
possess interesting non-diffracting and self-reconstructive properties upon encountering an obstacle.
Here the generation and properties of these novel laser beams will be discussed in detail.
Furthermore it is well known that these novel laser beams prove highly useful when incorporated
into an optical trapping system hence we will illustrate the effects on a trapped particle when
incorporating a Laguerre-Gaussian beam carrying a topological charge of one. It is expected that the
trapped particle should rotate due to the transfer of orbital angular momentum. The knowledge gained from beam shaping and the means to trap micron sized particles optically
allows one the ability to incorporate this technique in a number of fields, including the promising
field of microfluidics. This is an emerging field that deals with investigating fluid properties at the
nano and microlitre regime. Optical tweezers integrated into a microfluidic device are beneficial
since they are an adequate tool for measuring fluid flow using Stokes’ Law. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2011.
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Laser light scattering studies on association behavior of polymer chains in solution. / CUHK electronic theses & dissertations collectionJanuary 2001 (has links)
by Niu Aizhen. / "Mar., 2001." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.
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Angular distribution of wavelength-shift and intensity in laser air spark scattering.January 1985 (has links)
by Iu Chun-ho. / Bibliography: leaves 80-81 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1985
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