Dissertations / Theses on the topic 'Beam shaping'
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Litvin, Igor A. "Intra–cavity laser beam shaping." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4018.
Full textENGLISH ABSTRACT: There are many applications where a Gaussian laser beam is not ideal, for example, in areas such as medicine, data storage, science, manufacturing and so on, and yet in the vast majority of laser systems this is the fundamental output mode. Clearly this is a limitation, and is often overcome by adapting the application in mind to the available beam. A more desirable approach would be to create a laser beam as the output that is tailored for the application in mind – so called intra-cavity laser beam shaping. The main goal of intra-cavity beam shaping is the designing of laser cavities so that one can produce beams directly as the output of the cavity with the required phase and intensity distribution. Shaping the beam inside the cavity is more desirable than reshaping outside the cavity due to the introduction of additional external losses and adjustment problems. More elements are required outside the cavity which leads to additional costs and larger physical systems. In this thesis we present new methods for phase and amplitude intra– cavity beam shaping. To illustrate the methods we give both an analytical and numerical analysis of different resonator systems which are able to produce customised phase and intensity distributions. In the introduction of this thesis, a detailed overview of the key concepts of optical resonators is presented. In Chapter 2 we consider the well–known integral iteration algorithm for intra–cavity field simulation, namely the Fox–Li algorithm and a new method (matrix method), which is based on the Fox–Li algorithm and can decrease the computation time of both the Fox–Li algorithm and any integral iteration algorithms. The method can be used for any class of integral iteration algorithms which has the same calculation integrals, with changing integrants. The given method appreciably decreases the computation time of these algorithms and approaches that of a single iteration. In Chapter 3 a new approach to modeling the spatial intensity profile from Porro prism resonators is proposed based on rotating loss screens to mimic the apex losses of the prisms. A numerical model based on this approach is presented which correctly predicts the output transverse field distribution found experimentally from such resonators. In Chapter 4 we present a combination of both amplitude and phase shaping inside a cavity, namely the deployment of a suitable amplitude filter at the Fourier plane of a conventional resonator configuration with only spherical curvature optical elements, for the generation of Bessel–Gauss beams as the output. In Chapter 5 we present the analytical and numerical analyses of two new resonator systems for generating flat–top–like beams. Both approaches lead to closed form expressions for the required cavity optics, but differ substantially in the design technique, with the first based on reverse propagation of a flattened Gaussian beam, and the second a metamorphosis of a Gaussian into a flat–top beam. We show that both have good convergence properties, and result in the desired stable mode. In Chapter 6 we outline a resonator design that allows for the selection of a Gaussian mode by diffractive optical elements. This is made possible by the metamorphosis of a Gaussian beam into a flat–top beam during propagation from one end of the resonator to the other. By placing the gain medium at the flat–top beam end, it is possible to extract high energy in a low–loss cavity.
AFRIKAANSE OPSOMMING: Daar is verskeie toepassings waar ʼn Gaussiese laser bundel nie ideaal is nie, in gebiede soos mediese veld, stoor van data, vervaardiging en so meer, en tog word die meeste laser sisteme in die fundamentele mode bedryf. Dit is duidelik ’n beperking, en word meestal oorkom deur aanpassing van die toepassing tot die beskikbare bundel. ’n Beter benadering sou wees om ʼn laser bundel te maak wat afgestem is op die toepassing - sogenaamde intra-resonator bundel vorming. Die hoofdoel van intra-resonator bundel vorming is om resonators te ontwerp wat direk as uitset kan lewer wat die gewenste fase en intensiteits-distribusie vertoon. Vorming van die bundel in die resonator is voordeliger omdat die vorming buite die resonator tot addisionele verliese asook verstellings probleme bydra. Meer elemente word benodig buite die resonator wat bydra tot hoër koste en groter sisteme. In hierdie tesis word nuwe fase en amplitude intra-resonator bundelvormings metodes voorgestel. Om hierdie metode te demonstreer word analitiese en numeriese analises vir verskillende resonator sisteme wat aangepaste fase en intensiteit distribusies produseer, bespreek. In die inleiding van die tesis word ʼn detailleer oorsig oor die sleutel konsepte van optiese resonators voorgelê. In hoofstuk 2 word die bekende integraal iterasie algoritme vir intraresonator veld simulasie, naamlik die Fox-Li algoritme, en ʼn nuwe metode (matriks metode), wat gebaseer is op die Fox-Li algoritme, en die berekeningstyd van beide die Fox-Li algoritme en enige ander integraal iterasie algoritme verminder. Die metode kan gebruik word om enige klas van integraal iterasie algoritmes wat dieselfde berekenings integrale het, met veranderde integrante (waar die integrand die veld van die lig golf is in die geval van die Fox-Li algoritme, IFTA, en die skerm metode. Die voorgestelde metode verminder die berekeningstyd aansienlik, en is benaderd die van ʼn enkel iterasie berekening. In hoofstuk 3 word ʼn nuwe benadering om die modellering van die ruimtelike intensiteitsprofiel van Porro prisma resonators, gebaseer op roterende verliese skerms om die apeks-verliese van die prismas te benader, voorgestel. ʼn Numeriese model gebaseer op hierdie benadering wat die uitset van die transversale veld distribusie in eksperimentele resonators korrek voorspel, word voorgestel. In hoofstuk 4 word ʼn tegniek vir die generering van Bessel-Gauss bundels deur die gebruik van ʼn kombinasie van amplitude en fase vorming in die resonator en ʼn geskikte amplitude filter in die Fourier vlak van ʼn konvensionele resonator konfigurasie met optiese elemente wat slegs sferiese krommings het, voorgestel. In hoofstuk 5 word die analitiese en numeriese analises van twee nuwe resonator sisteme vir die generering van sogenaamde “flat–top” bundels voorgestel. Beide benaderings lei na ʼn geslote vorm uitdrukking vir die resonator optika wat benodig word, maar verskil noemenswaardig in die ontwerptegniek. Die eerste is baseer op die terug voortplanting van plat Gaussiese bundel, en die tweede op metamorfose van Gaussiese “flat-top” bundel. Ons toon aan dat beide tegnieke goeie konvergensie het, en in die gevraagde stabiele modus lewer. In hoofstuk 6 skets ons die resonator ontwerp wat die selektering van ʼn Gaussiese modus deur diffraktiewe optiese element moontlik maak. Dit word moontlik deur die metamorfose van ’n Gaussiese bundel na ʼn “flat-top” gedurende die voortplanting van die een kant van die resonator na die ander. Deur die wins medium aan die “flat–top” kant van die bundel te plaas word dit moontlik om hoë energie te onttrek in ʼn lae verlies resonator.
Zeng, Danyong. "ANNULAR BEAM SHAPING AND OPTICAL TREPANNING." Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2593.
Full textPh.D.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Mechanical Engineering
Mi, Yongcui. "Novel beam shaping and computer vision methods for laser beam welding." Licentiate thesis, Högskolan Väst, Avdelningen för produktionssystem (PS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-16970.
Full textLasersvetsning används i stor utsträckning i olika industrisektorer på grund av dess unika fördelar. Det finns emellertid fortfarande utmaningar, såsom rätt positionering av laserstrålen vid genomträngningssvetsning av T-fogar och hantering av varierande spaltbredd längs fogen vid svetsning av stumfogar. Sådana problem förväntas kunna lösas med avancerade metoder för automatisering, metoder som också förväntas ge fördjupade kunskaper om processen. Syftet med detta arbete är att ta itu med dessa problem med hjälp av en teknik för lasereffektens fördelning på arbetsstycket, s.k. beam shaping. Det sker med hjälp av en ny typ av i realtid deformerbar spegel tillsammans med bildbehandling av kamerabilder från processen. För- och nackdelar med detta tillvägagångssätt undersöks.Beam shaping åstadkoms med hjälp av ny typ av deformerbart spegelsystem som integreras i en industriell processoptik. Tillsammans med en vågfrontsensor bildas ett adaptivt system för beam shaping med en svarstid på 10 ms. Processen övervakas av en kamera linjerad koaxialt med laserstrålen. För att kunna ta bilder av svetspunkten belyses den med ljus av lämplig våglängd, och kameran är försedd med ett motsvarande optiskt filter. Försök har utförts med svetsning utan tillsatsmaterial, direkt på plåtar, svetsning utan s.k. nyckelhål, för att förstå effekten av beam shaping på svetssmältans geometri. Gauss fördelade cirkulära och elliptiska former, långsträckta både tvärs och längs svetsriktningen har studerats. Bilder från svetssmältan har analyserats och även mikrostrukturen i tvärsnitt från de svetsade plåtarna. Resultaten visar att svetssmältans geometri kan modifieras signifikant genom beam shaping med hjälp av det deformerbara spegelsystemet. Genomträngningssvetsning av T-fogar med avvikelser relativt foglinjens centrum genomfördes för att studera potentialen i att använda maskininlärning för att fånga processens tillstånd. Resultaten visade att maskininlärning kan nå tillräcklig prestanda för detektering och skattning av denna avvikelse. Något som också kan användas för återkopplad styrning. Flerdimensionell processdata har samlats i realtid och analyserats med hjälp av bildbehandlingsmetoder. Dessa data avslöjar brister i nuvarande simuleringsmodeller,vilket i sin tur hjälper till med att bättre förstå och styra lasersvetsning.Resultaten från detta arbete uppvisar en god potential i att använda de föreslagna metoderna för att lösa relevanta utmaningar inom lasersvetsning.
Till licentiatuppsats hör 2 inskickade artiklar, som visas inte nu.
Sinigardi, Stefano <1985>. "Laser driven proton acceleration and beam shaping." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6230/.
Full textRatsibi, Humbelani Edzani. "Laser drilling of metals and glass using zero-order bessel beams." University of the Western Cape, 2013. http://hdl.handle.net/11394/5428.
Full textThis dissertation consists of two main sections. The first section focuses on generating zero order Bessel beams using axicons. An axicon with an opening angle y = 5⁰ was illuminated with a Gaussian beam of width ω₀ = 1.67 mm from a cw fiber laser with central wavelength λ = 1064 nm to generate zero order Bessel beams with a central spot radius r₀ = 8.3 ± 0.3 μm and propagation distance ½zmax = 20.1 ± 0.5 mm. The central spot size of a Bessel beam changes slightly along the propagation distance. The central spot radius r₀ can be varied by changing the opening angle of the axicon, y, and the wavelength of the beam. The second section focuses on applications of the generated Bessel beams in laser microdrilling. A Ti:Sapphire pulsed femtosecond laser (λ = 775 nm, ω₀ = 2.5 mm, repetition rate kHz, pulse energy mJ, and pulse duration fs) was used to generate the Bessel beams for drilling stainless steel thin sheets of thickness 50 μm and 100 μm and microscopic glass slides 1 mm thick. The central spot radius was r₀ = 15.9 ± 0.3 μm and ½zmax = 65.0 ± 0.5 mm. The effect of the Bessel beam shape on the quality of the holes was analysed and the results were discussed. It was observed that Bessel beams drill holes of better quality on transparent microscopic glass slides than on stainless steel sheet. The holes drilled on stainless steel sheets deviated from being circular on both the top and bottom surface for both thicknesses. However the holes maintained the same shape on both sides of each sample, indicating that the walls are close to being parallel. The holes drilled on the glass slides were circular and their diameters could be measured. The measured diameter (15.4±0.3 μm) of the hole is smaller than the diameter of the central spot (28.2 ± 0.1 μm) of the Bessel beam. Increasing the pulse energy increased the diameter of the drilled hole to a value close to the measured diameter of the central spot.
Rafayelyan, Mushegh. "Singular beam shaping from spin-orbit flat optics." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0583/document.
Full textIt is well-known that paraxial coherent electromagnetic fields can be completelycharacterized in terms of their radial and azimuthal spatial degrees of freedom in the transverse planethat add to the polarization degree of freedom and wavelength. In this work we address two mainissues of paraxial beam shaping that are the modality and the polychromaticity in the context of flatopticsthat we address by introducing novel concepts of spin-orbit optical elements. Namely, the‘modal q-plate’ and the ‘Bragg-Berry q-plate’. On the one hand, modal q-plate converts an incidentfundamental Gaussian beam into a Laguerre-Gaussian beam of given radial and azimuthal indices,hence going beyond the capabilities of conventional q-plates that only control the azimuthal degreeof freedom, i.e. the orbital angular momentum content of light. Towards experimental realization ofmodal q-plates, two approaches are developed: one based on artificially nanostructured glasses andanother based on naturally self-organized liquid crystal topological defects. On the other hand,Bragg-Berry q-plate consist of mirror-backed inhomogeneous thin film of chiral liquid crystal(cholesteric) that provides fully efficient spin-orbit beam shaping over broad spectral range of theincident beam, in contrast to the conventional q-plates that are designed for single wavelength.Furthermore, ultra-broadband spin-orbit beam shaping is achieved by inducing an extra modulationof the supramolecular twisted structure of the cholesteric liquid crystal along the propagationdirection. We also show that the presence of a back-mirror allows a powerful spatio-temporal controlof the polarization vectorial properties of the light fields generated by Bragg-Berry q-plate
Maigyte, Lina. "Shaping of light beams with photonic crystals : spatial filtering, beam collimation and focusing." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/277571.
Full textLa recerca desenvolupada en el marc d'aquesta tesi doctoral és un estudi teòric, numèric i experimental de la modificació de la forma de feixos de llum (filtratge espacial, col·limació i focalització) en el rang visible de freqüències utilitzant estructures de cristall fotònic. Els cristalls fotònics (CFs) són materials amb una modulació periòdica de l'índex de refracció en l'escala de la longitud d'ona, i són principalment coneguts per les seves propietats relacionades amb la dispersió temporal. Tot i això, la dispersió espacial també pot ser modificada mitjançant CFs, fet que permet controlar les propietats espacials de feixos monocromàtics de llum. En la primera part de la tesi, mostrem experimentalment el fet que certes modificacions de la dispersió espacial en CFs poden donar lloc a filtratge espacial (angular) de feixos de llum. L'estudi es focalitza en la millora de l'eficiència del filtratge espacial mitjançant la introducció de "chirp" (la variació del període longitudinal de l'estructura) en el CF. A més, per tal d'incrementar l'efecte considerem diferents estructures i materials. El treball presentat en aquesta tesi doctoral acosta a la realitat la creació d'una nova generació de filtres espacials per a circuits micro-fotònics i micro-dispositius. La segona part d'aquest estudi se centra en l'anàlisi teòric, numèric i experimental de la formació de dispersió espacial negativa en CFs, la gual dóna lloc a efectes de col·limació i focalització un cop travessat el CF. Les idees desenvolupades en aquesta tesi doctoral també són aplicables a sistemes amb pèrdues, en particular a CFs metàl·lics. Els resultats de les simulacions mostren l'existència d'ambdós efectes, filtratge espacial i focalització, en CFs metàl·lics.
Yang, Zhengyi. "Optical and acoustic beam shaping for imaging and manipulation." Thesis, University of Dundee, 2014. https://discovery.dundee.ac.uk/en/studentTheses/18d650a0-53ba-4f4d-9d61-78c3a6b68bf6.
Full textLiu, Lihong. "Beam shaping of incoherent white light with faceted structure." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAD010.
Full textBeam shaping of incoherent white light with a large spectrum is proposed in this PhD thesis. The objective was to realize an arbitrary irradiance map on a target plane using a faceted structure. To maintain the design result within the geometrical optics domain, large facet element dimensions are required to obtain usable results. Each facet element can slightly tilt along its own axes to deflect the incident light, either by reflection, either by transmission. The calculation of the tilt angles is made by an analytical approach, and also by automatic optimization with Zemax. Several quality factors are proposed in order to qualify the illumination/irradiance chart on the screen. Because of the required tolerances on the fabrication technique, we show that it is more interesting to design a transmissive structure than a reflective one. With a new additive technology, a structure is realized successfully, showing the interest of the concept
Victor, Brian M. "Custom Beam Shaping for High-Power Fiber Laser Welding." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1238014676.
Full textZhang, Shuyan. "Spatial beam shaping of high-power ultrashort laser pulses." W&M ScholarWorks, 2007. https://scholarworks.wm.edu/etd/1539623522.
Full textHoldsworth, Adrian Richard. "Brightness conserving optical systems for high power diode lasers." Thesis, Heriot-Watt University, 1999. http://hdl.handle.net/10399/583.
Full textWellburn, Daniel. "Circular laser beam intensity profile shaping for uniform surface treatments." Thesis, University of Liverpool, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.533912.
Full textCheng, Wen. "Optical Vortex Beams: Generation, Propagation and Applications." University of Dayton / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1375370902.
Full textAment, Craig A. "High numerical aperture axial and transverse beam shaping using diffractive optics." Honors in the Major Thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1348.
Full textBachelors
Sciences
Physics
Dimaria, Jeffrey V. "Plasmonic control of light emission for enhanced efficiency and beam shaping." Thesis, Boston University, 2014. https://hdl.handle.net/2144/10981.
Full textInGaN alloys and related quantum structures are of great technological importance for the development of visible light emitting devices, motivated by a wide range of applications, particularly solid-state lighting. The InxGa1-xN material system provides continuous emission tuning from the ultraviolet across the visible spectrum by changing the In content. InGaN/GaN quantum wells (QW) also provide an efficient medium for electroluminescence for use as light emitting diodes. It is well known, however, that increasing the In content degrades the internal quantum efficiency of these devices, particularly in the green region of the spectrum. These limitations must be overcome before efficient all-solid-state lighting can be developed beyond the blue-green region using this material system. Recently, the application of plasmonic excitations supported by metallic nanostructures has emerged as a promising approach to address this issue. In this work, metallic nanoparticles (NPs) and nanostructures that support plasmonic modes are engineered to increase the local density of states of the electromagnetic field that overlaps the QW region. This leads to an enhancement of the spontaneous emission rate of the QW region mediated by direct coupling into the plasmonic modes of the nanostructure. Energy stored in these modes can then scatter efficiently into free-space radiation, thereby enhancing the light output intensity. The first section of this thesis concerns the enhancement of InGaN/GaN QW light emission by utilizing localized surface plasmon resonances (LSPRs) and lattice surface modes of metal NP arrays. This work comprises a detailed study of the effect of geometry variations of Ag NPs on the LSPR wavelength, and the subsequent demonstration of photoluminescence intensity enhancement by Ag NPs in the vicinity of InGaN multiple QWs. The second section of this thesis concerns the far-field control of QW emission utilizing metallic nanostructures that support plasmonic excitations. This includes a study of the dispersion and competing effects of a metallic NP-film system, and the demonstration of beam collimation and unidirectional diffraction utilizing a similar geometry. These results may find novel applications in the emerging field of solid-state smart lighting.
Du, Plessis Anton. "A characterization of beam shaping devices and a tunable Raman laser." Thesis, Stellenbosch : University of Stellenbosch, 2003. http://hdl.handle.net/10019.1/16313.
Full textENGLISH ABSTRACT: The efficient manipulation of various nonlinear optical processes frequently requires the shaping of the laser beams used for these processes. Three beam shaping techniques were investigated in this thesis. The focussing of Gaussian laser beams was investigated analytically, in order to efficiently manipulate the focussed beam characteristics. The beam-shaping characteristics of a diffractive optical element (DOE) was investigated numerically, which illustrates the beamshaping capability of the DOE, and identifies the critical parameters in experimental situations. The use of a waveguide as beam shaping device was investigated analytically and experimentally, and characterized for use with the available tunable laser sources. A Raman laser, or Raman shifter, employs stimulated vibrational Raman scattering to generate laser radiation at shifted frequencies. The waveguide was successfully applied as a beam shaping device in the Raman laser system, for optimisation of the process. The Raman laser system was investigated experimentally and characterized for use with the available tunable laser sources. The successful generation of laser radiation at shifted frequencies illustrates the usefulness of the system for generating tunable red-shifted frequencies. The results of this work allow the simple and efficient application of the Raman laser to generate laser radiation at shifted frequencies, in particular tunable infrared laser radiation which is desirable for molecular spectroscopy.
AFRIKAANSE OPSOMMING: Nie-liniêre optiese prosesse kan meer effektief benut word deur die vervorming van die laserbundels wat gebruik word in die prosesse. In hierdie tesis word drie laserbundel-vervormings tegnieke ondersoek. Die fokussering van Gaussiese laserbundels word analities ondersoek, om die gefokusseerde bundel se eienskappe effektief te manipuleer. Die bundel-vervormings eienskappe van ’n diffraktiewe optiese element word numeries ondersoek, wat die effektiwiteit van die bundelvervorming en die sensitiewe parameters in die sisteem uitwys. Die gebruik van ’n golfgeleier as ’n bundel-vervormings tegniek word ook analities en eksperimenteel ondersoek, en gekarakteriseer vir gebruik met die gegewe golflengte-verstelbare laser sisteme. ’n Raman laser, wat gestimuleerde vibrasionele Raman verstrooiing gebruik om laser lig te genereer by Stokes-verskuifde frekwensies, word ondersoek. Die golfgeleier word effektief gebruik as ’n bundel-vervormings tegniek in die Raman laser, om die bogenoemde nie-liniêre proses te optimeer. Die Raman laser was eksperimenteel ondersoek en gekarakteriseer vir gebruik met die gegewe golflengte-verstelbare lasers. Laser lig by verskuifde golflengtes is suksesvol gegenereer, wat die bruikbaarheid van die sisteem illustreer. Van belang is spesifiek verstelbare infrarooi laser lig, wat gebruik kan word in die laser-spektroskopie van molekules. Die resultate van hierdie werk lei tot die eenvoudige en effektiewe gebruik van die Raman laser, om langer golflengtes in die infrarooi gebied te genereer met ’n gegewe laser in die sigbare gebied.
Penner, Robert Scott. "Focusing, wavelength tuning, beam steering and beam shaping of circular grating surface emitting distributed Bragg reflector lasers." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/284042.
Full textBurnham, Daniel Richard. "Microscopic applications of holographic beam shaping and studies of optically trapped aerosols /." St Andrews, 2009. http://hdl.handle.net/10023/699.
Full textStefansson, Gudmundur, Suvrath Mahadevan, Leslie Hebb, John Wisniewski, Joseph Huehnerhoff, Brett Morris, Sam Halverson, et al. "Toward Space-like Photometric Precision from the Ground with Beam-shaping Diffusers." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/626043.
Full textBurnham, Daniel R. "Microscopic applications of holographic beam shaping and studies of optically trapped aerosols." Thesis, University of St Andrews, 2009. http://hdl.handle.net/10023/699.
Full textLi, J. "Advanced laser beam shaping using spatial light modulators for material surface processing." Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3022554/.
Full textZhang, Chong. "THERMAL MODELING AND LASER BEAM SHAPING FOR MICROVIAS DRILLING IN HIGH DENSITY PACKAGING." Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2255.
Full textPh.D.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Mechanical Engineering PhD
Han, Jiho. "Phase modulated fibre amplifier array for high power real-time arbitrary beam shaping." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267906.
Full textMcDonald, Craig. "Applications of optical manipulation for low cost implementation, beam shaping and biophysical force measurements." Thesis, University of Dundee, 2017. https://discovery.dundee.ac.uk/en/studentTheses/35080e80-77ec-4442-826c-cab158e524fd.
Full textNylk, Jonathan. "Advanced light-sheet and structured illumination microscopy techniques for neuroscience and disease diagnosis." Thesis, University of St Andrews, 2016. http://hdl.handle.net/10023/10842.
Full textKong, Fanqi. "High-Order Harmonic Generation with Structured Beams." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39609.
Full textNamarathne, Dinithi L. "Measuring intensity dependent optical nonlineartities without sample damage using higher order vortex beams." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/129569/9/Dinithi_Namarathne_Thesis.pdf.
Full textBarcík, Peter. "Rozložení relativní variance optické intenzity ve svazcích." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219880.
Full textJiang, Miao. "DESIGNS AND APPLICATIONS OF PLASMONIC METAMASKS FOR TOPOLOGICAL DEFECT ENGINEERING AND MANUFACTURING OF PANCHARATNAM FLAT OPTICAL ELEMENTS." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1533742796947775.
Full textRudhall, Andrew Peter. "Ultrashort laser pulse shaping for novel light fields and experimental biophysics." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/3682.
Full textChung, Te-yuan. "THERMAL MANAGEMENT, BEAM CONTROL,AND PACKAGING DESIGNS FOR HIGH POWER." Doctoral diss., University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3879.
Full textPh.D.
Other
Optics and Photonics
Optics
Serkan, Mert Kirkici Hulya. "Laser beam shaping optical system design methods and their application in edge-emitting semiconductor laser-based lidar systems." Auburn, Ala., 2007. http://repo.lib.auburn.edu/2007%20Fall%20Dissertations/Serkan_Mert_22.pdf.
Full textBaig, Sarfaraz Niaz Ali. "Soft Lithographic Fabrication of Micro Optics and Integrated Photonic Components." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_theses/179.
Full textYi, Fan, and n/a. "Optimal Algorithmic Techniques of LASIK Procedures." Griffith University. School of Engineering, 2006. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20070216.152339.
Full textYi, Fan. "Optimal Algorithmic Techniques of LASIK Procedures." Thesis, Griffith University, 2006. http://hdl.handle.net/10072/368097.
Full textThesis (Masters)
Master of Philosophy (MPhil)
School of Engineering
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He, Weiyi. "Optical Design of Beam Shaping Optics for Camera Probe and LED Light Illumination Used for Minimally Invasive Abdominal Surgery." Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3532.
Full textKropáč, Ondřej. "Návrh tvarovacího systému pro laserový svazek." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219163.
Full textFournier, Florian. "FREEFORM REFLECTOR DESIGN WITH EXTENDED SOURCES." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3146.
Full textPh.D.
Optics and Photonics
Optics and Photonics
Optics PhD
Mourka, Areti. "Probing the modal characteristics of novel beam shapes." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/4287.
Full textJabbour, Toufic. "DESIGN, ANALYSIS, AND OPTIMIZATION OF DIFFRACTIVE OPTICAL ELEMENTS UNDER HIGH NUMERICAL APERTURE FOCUSING." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2837.
Full textPh.D.
Optics and Photonics
Optics and Photonics
Optics PhD
BENKHEROUROU, SAHNOUNE SOURAYA. "Contribution a l'uniformisation du faisceau laser gaussien collimate par holographie numerique." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13084.
Full textCHEN, WEIBIN. "Focus Engineering with Spatially Variant Polarization for Nanometer Scale Applications." University of Dayton / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1259871061.
Full textZhou, Sichao. "Complex Optical Fields Generation Using a Vectorial Optical Field Generator." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1461689435.
Full textHantl, Josef. "Tvarování laserového svazku." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219125.
Full textNoori, Rahim Abadi Seyyed Mohammad Ali. "Investigation of Melt Pool Thermo-hydrodynamic Behaviour inLaser Beam Welding ofTi-6Al-4V through Numerical Simulation." Licentiate thesis, Högskolan Väst, Avdelningen för svetsteknologi (SV), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-17410.
Full textLaser är en effektiv och allmänt använd värmekälla vid svetsning och additiv tillverkning. Den har några viktiga fördelar jämfört med andra konventionella värmekällor såsom elektronstråle och elektrisk ljusbåge, nämligen: den kan ofta användas till komplicerade svetsgeometrier, och den kan producera stora komponenter. Lasersvetsning involverar olika sammansatta fysikaliska fenomen såsom värmeöverföring, metallsmältning, flöde, stelning, ytdeformation, avdunstning och i vissa fall förångning. Syftet med mitt forskningsarbete är tvåfaldigt: att få en djupare processförståelse och att förbättra modellens tillförlitlighet. Fördjupad processförståelse eftersträvades för att förstå hur formen på laserstrålen påverkar svetssmältan. För att uppnå förbättrad modellsäkerhet behövs experimentella data av hög kvalitet som representerar processen. Således utfördes 3D-validering av smältgeometrin medan det vanligtvis var 2D i tidigare forskningsarbeten. Dessutom har en ny modell för laserabsorption föreslagits. I forskningen har numerisk strömningssimulering (Computational Fluid Dynamics) använts för att simulera processen och en numerisk lösare, som kan spåra deformationen av den rörliga smälta ytan, är utveckladi programvaran OpenFOAM. Beträffande laserstrålens utbredning visar resultaten att svetssmältans storlek och även svetssmältansflöde modifieras genom att laserstråleformen förlängs. Medan den förra är känd från tidigare experimentella studier upptäcktes den senare inte före denna studie eftersomdet icke-transparenta mediet hindrar optisk observation. Nya (in-process) kvantitativa mätningar utförda av en projektpartner har använts för att testa modellerna. Svagheter i den tidigare absorptionsmodellen framhävdes, liksom begränsningarna i den föreslagna modellen. Slutligen visade resultaten att den föreslagna modellen där laserabsorptionen är en funktion av lokala ytförhållanden ledde till en bättre overensstämmelse med mätningar jämfört med den tidigare modellen med konstant laserabsorbtion. Den maximala avvikelsen jämfört med experimentell mätning, som observerades med avseende på smältbassängsdjupet, kunde reduceras till cirka 10%.
Till licentiatuppsats hör 2 inskickade artiklar, som inte visas nu.
Ouadghiri, Idrissi Ismail. "Nonlinear instabilities and filamentation of Bessel beams." Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCD071/document.
Full textBessel beams are solutions of Helmholtz equation. They can propagate while conserving their transverse intensity profile in space even in filamentation regime. This feature is very advantageous in high power laser applications such as plasma waveguide generation and laser ablation because they can generate homogeneous plasma channels in dielectrics. However, for moderate to low focusing conditions, Bessel pulses can sustain nonlinear instabilities, which consist in the modulation of the central core intensity along the propagation. Such a feature can prevent efficient energy deposition which hampers the applicability of Bessel pulses. The aim of this thesis is to investigate the possibility to control laser-generated plasma channels using spatially-reshaped Bessel pulses. In a first part, we have developed an experimental method based on a spatial light modulator to modify the evolution of the on-axis intensity of Bessel beams in the linear propagation regime. To study and control Kerr-induced instabilities, we developed, in a second part, a novel model based on four wave mixing interactions in Bessel beams. We have then demonstrated a novel approach to control these instabilities via on-axis intensity shaping. Bessel filamentation models in transparent media were then studied. Most models used in literature are based on nonlinear Schrödinger equation for light propagation and Drude model for laser-matter coupling. Experimental results on Bessel filamentation in glass showed propagation-invariant features in contrast with numerical simulations. Several corrections to this model were discussed. Our results show that such models are insufficient to explain our experimental results and thus the need to develop a more suitable one
Hampl, Martin. "Prostorové dělení optických svazků." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-233502.
Full textChen, Sen-Yong. "Phonon Modulation by Polarized Lasers for Material Modification." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5159.
Full textPh.D.
Doctorate
Optics and Photonics
Optics and Photonics
Optics
Koenen, Christian [Verfasser], Thomas F. [Akademischer Betreuer] Eibert, Thomas F. [Gutachter] Eibert, and Ulrich [Gutachter] Stroth. "Steerable Millimeter-Wave Gaussian Beam Shaping Phased Array Antenna for Doppler Reflectometry of Nuclear Fusion Plasma Turbulence in ASDEX Upgrade Tokamak / Christian Koenen ; Gutachter: Thomas F. Eibert, Ulrich Stroth ; Betreuer: Thomas F. Eibert." München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/1207075027/34.
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