Dissertations / Theses on the topic 'Laser stabilization'
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1
Kwee, Patrick. "Laser characterization and stabilization for precision interferometry." Hannover Technische Informationsbibliothek und Universitätsbibliothek Hannover, 2010. http://d-nb.info/1000893626/34.
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Pugla, Sarika. "Ultrastable high finesse cavities for laser frequency stabilization." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490789.
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Lasers with stability of the order of 10.15 or more form the basis of frequency metrology and several other experiments including gravitational wave detection, high-precision spectroscopy and tests of relativity. This thesis describes the frequency stabilization of 1064nm, Nd:YAG lasers to ultra-stable, high finesse Fabry-Perot cavities using the PoundDrever- Halliocking scheme. These lasers will be used as flywheel oscillators for optical atomic clocks. The first part of this thesis describes the design and development of a stable laser using a cryogenic, all-sapphire, high finesse Fabry-Perot cavity. Two similar systems have been developed and the beat frequency between the two systems has been measured. This beat frequency measurement provides a measure of relative stability of the laser. In addition experiments have also been performed with ULE (ultra-low expansivity) glass cavities. The thermal expansivity of ULE has a zero near room temperature and a turning point was found. A beat frequency measurement was made for a pair of lasers locked to ULE cavities.The frequency stabilization techniques applied to the lasers described in this thesis will be used for future frequency standards based on optical transitions.
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Sievers, Charles A. (Charles Anders) 1979. "Frequency stabilization for a 486nm dye-ring laser." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32754.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2004.Includes bibliographical references (p. 43).
For my thesis, I worked towards using two reference cavities to provide frequency stabilization to a 486nm dye-ring laser. After a doubling cavity doubles the frequency to 243nm, the laser beam is used to excite ground state hydrogen to the 2S state: the first step of an experiment to accurately measure the 2S-NS transitions of hydrogen and measure the Lamb shift and Rydberg's constant. Two stabilization cavities were used to prevent the frequency from drifting and to narrow the laser's line-width. I aligned the majority of the optics and coupling light into fiber-optic cables and Fabrey-Perot cavities. Coupling light into a high finesse Fabrey-Perot cavity requires matching the radius of curvature of constant phase of the laser with the geometry of the cavity. To do this, I first measured the physical properties of the laser beam and then numerical arrived at a solution using two lenses to match the conditions imposed by the cavity's geometry. I aligned the cavity and then observed a Pound-Drever-Hall error signal. This error signal will be fed back into the laser to stabilize the frequency. It is anticipated that when the electronics to utilize the error signals are completed, the laser frequency will be stabilized to a hundred hertz, an four order of magnitude improvement over the stability provided by the commericial laser.
by Charles A. Sievers.
S.B.
4
Abu-Taha, M. I. A. "Optoacoustic frequency stabilization of a carbon dioxide laser." Thesis, Keele University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377921.
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Kwee, Patrick [Verfasser]. "Laser characterization and stabilization for precision interferometry / Patrick Kwee." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover, 2010. http://d-nb.info/1000893626/34.
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Ahmed, H. H. I. S. "Frequency selection and stabilization of semiconductor laser diode systems." Thesis, Swansea University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.635861.
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Different types of semiconductor diode laser sources were tested in a range of spectroscopic and metrological applications to demonstrate the versatility of our laser set-up implementations. Two main topics were pursued in this study: (a) experiments on absorption spectroscopy were carried out using external cavity laser diode modules in the wavelength range (410 – 1550 nm) while vertical cavity surface emitting lasers (VCSELs) were used in the experiments involving opto-galvanic spectroscopy and laser frequency stabilization at 800.6 nm. Absorption experiments were performed for the quantitative detection of (atmospheric) trace gases such as H2O, CO, and CO2. The Tuneable Diode Laser Absorption Spectroscopy (TDLAS) was realised without the need for sophisticated detection electronics (e.g. lock-in amplifiers, etc.). A notebook-data acquisition system in conjunction with dedicated software developed during this study was fully adequate and allowed us to generate “any” desired shape of the modulation signal; and – after the data had been acquired – post-collection processing could be carried out (like averaging, noise removal, signal normalization, trend plots, etc.). In order to implement the opto-galvanic (OG) spectroscopy experiment, the opto-galvanic driver, control and detection unit was designed and built in-house. This electronic device was one of the centrepieces of the set-up for locking the laser diode frequency to an atomic transition in a hollow cathode discharge lamp. An integrated device such as the one required in this study is not available commercially. The observed OG signal revealed a series of sub-structures in the form of doublets (0.0074 nm or 4 GHz apart). The doublet frequency splitting results from the fact that VCSEL light is composed of two clearly-resolved spectral components, both linearly polarized, associated with transverse mode oscillation. Locking the laser frequency in the OG signal of the Argon transition at 800.6 nm was achieved using modulation of the injection current of the laser diode. This was done by feeding the OG signal into the data acquisition and control card to generate the suitable error signal (in magnitude and sign) to the laser current driver. This process was entirely controlled by a software program written during the course of this work. Incomplete attempts were made to couple the Fabry-Perout (FP) laser radiation to a fibre Bragg grating (FBG) due to some technical problems. Specifically, the fabricated FB didn’t match fully to any diodes available to us during the time of the experiments. Thus, only very weak feedback on FBG side-bands was observed which was insufficient to push the laser into single-wavelength oscillation.
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Cunado, Jose. "CONTROL AND STABILIZATION OF LASER PLASMASOURCES FOR EUV LITHOGRAPHY." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2746.
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Extreme Ultraviolet (EUV) sources rely on droplet laser plasmas for EUV generation. These sources consist of a small (30 μm diameter) droplet which is excited into plasma emitting EUV around 13.5 nm, the industry's chosen wavelength for EUV lithography (EUVL). These sources are the best candidates for the commercialization of EUVL allowing mass production of computer chips with 32 nm or even smaller feature size. However, the biggest challenges which EUV source developers encounter today are the issues of conversion efficiency (CE) and debris.In order to satisfy the technology requirements, the source will need to meet high levels of stability, performance, and lifetime. Our tin-doped droplet plasma has demonstrated high CE and low debris resulting in long lifetime. Long term stability is obtained through the use of novel tracking techniques and active feedback. The laser plasma targeting system combines optical illumination and imaging, droplet technology innovation, advanced electronics, and custom software which act in harmony to provide complete stabilization of the droplets. Thus, a stable, debris-free light source combined with suitable collection optics can provide useful EUV radiation power. Detailed description of the targeting system and the evaluation of the system will be presented.M.S.E.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering MSEE
8
Trad, Nery Marina [Verfasser]. "Laser power stabilization via radiation pressure / Marina Trad Nery." Hannover : Gottfried Wilhelm Leibniz Universität, 2021. http://d-nb.info/1234147564/34.
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Byrne, Nicole (Nicole Malenie). "Phase stabilization of laser beams in a cold atom accelerometer." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/96460.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 95-97).
A cold atom accelerometer measures the displacement of a proof mass of laser cooled atoms with respect to an instrument reference frame. The cold atom interferometer's reference frame is defined by a pair of specially prepared, counter-propagating laser beams, that measure inertially induced atom displacements with nm scale resolution. This corresponds to acceleration sensitivities comparable to state of the art electro-mechanical accelerometers. In dynamic environments, sensitivity is limited by the stability of the relative laser phase of the two interrogation laser beams, which is adversely affected by vibrations and temperature fluctuations of the interrogation beam optics. Without an independent measurement, the cold atom interferometer cannot distinguish platform acceleration from laser phase fluctuations, which thus are a potentially serious source of error. In this thesis, a Michelson optical interferometer and an optical feedback loop were used to stabilize the relative phase of the interrogation laser beams in a cold atom accelerometer. A digital controller stabilized the relative phase via an electro-optic phase modulator. This control loop's bandwidth encompasses 98.8% of the noise power as determined from the power spectral density of the open loop 795nm Michelson signal. Increasing the controller bandwidth would gain the system marginal improvement in noise reduction. At an atom interferometer dwell time of 1 msec, active laser phase stabilization improved the atom interferometer sensitivity; at an atom interferometer dwell time of 8msec, an improvement was no longer evident. Improvements to the laser phase stabilization system are proposed to increase atom interferometer stability at longer dwell times.
by Nicole Byrne.
S.M.
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Chong, Michael. "Optical power stabilization of a laser diode for qnd measurement." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5892/.
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La realizzazione di stati non classici del campo elettromagnetico e in sistemi di spin è uno stimolo alla ricerca, teorica e sperimentale, da almeno trent'anni. Lo studio di atomi freddi in trappole di dipolo permette di avvicinare questo obbiettivo oltre a offrire la possibilità di effettuare esperimenti su condesati di Bose Einstein di interesse nel campo dell'interferometria atomica. La protezione della coerenza di un sistema macroscopico di spin tramite sistemi di feedback è a sua volta un obbiettivo che potrebbe portare a grandi sviluppi nel campo della metrologia e dell'informazione quantistica.
Viene fornita un'introduzione a due tipologie di misura non considerate nei programmi standard di livello universitario: la misura non distruttiva (Quantum Non Demolition-QND) e la misura debole. Entrambe sono sfruttate nell'ambito dell'interazione radiazione materia a pochi fotoni o a pochi atomi (cavity QED e Atom boxes). Una trattazione delle trappole di dipolo per atomi neutri e ai comuni metodi di raffreddamento è necessaria all'introduzione all'esperimento BIARO (acronimo francese Bose Einstein condensate for Atomic Interferometry in a high finesse Optical Resonator), che si occupa di metrologia tramite l'utilizzo di condensati di Bose Einstein e di sistemi di feedback.
Viene descritta la progettazione, realizzazione e caratterizzazione di un servo controller per la stabilizzazione della potenza ottica di un laser. Il dispositivo è necessario per la compensazione del ligh shift differenziale indotto da un fascio laser a 1550nm utilizzato per creare una trappola di dipolo su atomi di rubidio. La compensazione gioca un ruolo essenziale nel miglioramento di misure QND necessarie, in uno schema di feedback, per mantenere la coerenza in sistemi collettivi di spin, recentemente realizzato.
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Stacey, John-Patrick. "Stabilization and control in a linear ion trap." Thesis, University of Oxford, 2003. http://ora.ox.ac.uk/objects/uuid:5c019c02-c313-4fb4-92f4-8a342dd5dbf6.
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This thesis describes experimental work towards developing a trapped ion quantum information processor. An existing ion trap apparatus was capable of trapping and laser-cooling single ions or small ion strings of 40 Ca+, and had been used for studies of quantum jumps and natural lifetime measurements in Ca. This thesis describes improvements in this apparatus, which have allowed the stability and the flexibility of experimental control of the ions to be greatly increased. This enabled experiments to read out the spin state of a single trapped ion, and to load ions with isotope selectivity through photoionization. The optical systems were improved by installation of new lasers, optical reference cavities, and a system of acousto-optic modulators for laser intensity switching and frequency control. The photon counting for fluorescence detection was improved, and a new photon time-of-arrival correlation circuit developed. This has permitted rapid and more sensitive detection of micromotion, and hence cancellation of stray fields in the trap. A study of resonant circuits in the low RF, high voltage (10 MHz, 1 kV) regime was carried out with a view to developing a new RF supply for the Paul trap with reduced noise and increased power. A new supply based on a helical resonator was built and used to trap ions. This technique has reduced noise and will permit higher secular frequencies to be attained in the future. A magnetic field B in the ion trap is used to define a quantization axis, and in one series of experiments was required to be of order 100 G to provide a substantial Zeeman splitting. A set of magnetic field coils to control the size and direction of B is described. The design of these posed some problems owing to an unforseen issue with the vacuum chamber. In short, it is magnetizable and acts to first approximation like a magnetic shield. The field coils had to be sufficiently substantial to produce the desired field at the ion even in the presence of this shielding effect, and dark resonance (and other) spectra with Zeeman splitting were obtained to calibrate the field using the ion as a probe. Finally, the thesis describes the successful loading of the ion trap by laser photoionization from a weak atomic beam. This involved two new lasers at 423 nm and 389 nm. Saturated absorption spectroscopy of neutral calcium is first described, then transverse excitation of an atomic beam in our vacuum chamber is used to identify all the main isotopes of calcium and confirm their abundances in our source (a heated sample of natural calcium). Finally, photoionization is used to load the trap. This has three advantages over electron-impact ionization. By avoiding an electron gun, we avoid charging of insulating patches and subsequent electric field drift as they discharge; the flux in the atomic beam and hence calcium (and other) deposits on the electrodes can be greatly reduced; and most importantly, the photoionization is isotope selective. Evidence is presented which suggests that even with an non-enriched source, the rare isotope 43 Ca can be loaded with reasonable efficiency. This isotope is advantageous for quantum information experiments for several reasons, but chiefly because its ground state hyperfine structure can act as a stable qubit.
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Drollinger, Cy Taylor. "Frequency stabilization of an external cavity diode laser employing digital control." Thesis, Montana State University, 2006. http://etd.lib.montana.edu/etd/2006/drollinger/DrollingerC0806.pdf.
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Zhu, Feng. "Carrier envelope phase stabilization of a femtosecond laser and iodine spectroscopy." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4274.
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The carrier envelope (CE) phase of a femtosecond laser was stabilized. The laser
produces an ultra stable comb of frequency spanning the visible region and basically is
an optical frequency synthesizer and ready for the frequency domain applications.
In this context, the CW stability of the Ti:sapphire laser is discussed to provide a
procedure for the femtosecond laser adjustments. In addition, the pulse trains emitted by
the femtosecond laser are described analytically to provide a theoretical basis for carrier
envelope phase stabilization.
An f to 2f interferometer was used to detect the carrier envelope offset frequency,
and a fast photo diode was employed to measure the repetition rate. Two similar
designed phase lock loops are used to stabilize both the carrier envelope offset frequency
and the repetition rate to the respective reference frequencies. The stability reaches
100mHz for the carrier envelope offset frequency and 10mHz for the repetition rate for a
period of up to an hour.
Doppler free iodine saturation spectroscopy was set up to provide a precise
frequency reference to which a CW dye laser can be locked on. The near future goal is to
accurately measure this frequency stabilized dye laser with the optical frequency
synthesizer.
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Hanke, Manuela Melanie [Verfasser]. "Laser frequency stabilization for the sub-SQL interferometer / Manuela Melanie Hanke." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2018. http://d-nb.info/1170355609/34.
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Borchers, Bastian. "Pushing frontiers in Carrier-Envelope Phase stabilization of ultrashort laser pulses." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2015. http://dx.doi.org/10.18452/17137.
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Die vorliegende Arbeit ist der Verbesserung der Carrier-Envelope Phasenstabilisierung von ultrakurzen Laserimpulsen gewidmet. Zur Realisierung von Fortschritten auf diesem Gebiet werden die grundlegenden Rauschquellen identifiziert, die das erzielbare Restphasenrauschen limitieren, und geeignete Maßnahmen zu deren Verringerung vorgeschlagen. Es wird gezeigt, dass sowohl die Messung der Carrier-Envelope Phase (CEP) als auch deren Kontrolle durch verschiedene Rauschbeiträge beeinträchtigt wird. Der Detektionsprozess ist dabei einerseits durch technische Rauschquellen beeinflusst, die vor allem in den verwendeten nichtlinearen Interferometern auftreten. Andererseits repräsentiert das Detektionsrauschen während der elektro-optischen Wandlung eine fundamentale Limitierung, da das optische Schrotrauschen sowie das Rauschen des Lichtdetektors die Messung der CEP unausweichlich beeinträchtigen. Es wird demonstriert, wie solche Beschränkungen durch geeignete Wahl der Interferometertopologie, bzw. durch Optimierung des spektralen Verbreiterungsmechanismus verringert werden können. Experimentell gelingt es dadurch den Signal-Rauschabstand der Phasenmessung um 20 Dezibel zu steigern. Hinsichtlich der CEP Kontrolle von Oszillatoren wird in dieser Arbeit ein neuartiges Doppelstabilisierungskonzept vorgestellt, welches eine feed-forward Stabilisierung, die auf einem akustooptischen Frequenzschieber beruht, mit einer klassischen Feedback Regelung kombinert. Mit diesem Konzept gelingt eine Reduzierung des Phasenrestrauschen auf beispiellose 20 Milliradian. Darüber hinaus werden weitere neue Stabilisierungskonzepte vorgestellt, die ohne Feedback zu dem Laseroszillator auskommen. Bei einem dieser Konzepte, handelt es sich um eine gepulste feed-forward Stabilisierung, die speziell für das Zusammenwirken mit einer Verstärkerstufe konzipiert ist. Erste experimentelle Ergebnisse zeigen, dass Phasenrestrauschen von weniger als 100 Milliradian auch für Verstärkersysteme erreichbar sind.The present thesis is dedicated to improvements of the carrier-envelope phase stabilization of ultrashort laser pulses. In order to realize such improvements, the fundamental noise sources are identified, and suitable measures for their reduction are proposed. It is shown that both, the measurement of the carrier-envelope phase (CEP) as well as its control are corrupted by different noise contributions. On the one hand, the detection process is influenced by technical noise sources, which arise especially in the used nonlinear interferometers. On the other hand, the detection noise in the electro-optic conversion represents a fundamental limitation, since the optical shot noise as well as the noise induced by the light detector inevitably influence the measurement of the CEP. It is demonstrated how such limitations can be minimized by a suitable choice of the interferometer topology and by an optimization of the spectral broadening process in a micro-structured fiber. This way an enormous improvement of the signal-to-noise ratio by 20 dB is obtained experimentally, which significantly reduces the limitation of detection noise. For controlling the CEP of mode-locked oscillators, a novel double stabilization scheme is introduced in this thesis, which combines a feed-forward stabilization based on an acousto-optic frequency shifter, with a classical feedback loop. This method enables a reduction of the residual phase jitter to an unprecedented value of 20 milliradian. Beyond that, several further concepts are introduced that are capable of stabilizing the CEP without any feedback to the laser oscillator. One of these concepts, represents a pulsed feed-forward stabilization, which is specifically designed for the use in combination with a subsequent amplification stage. First experimental results indicate that residual phase jitters of less than 100 milliradian are within reach also for amplified laser systems.
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Tröbs, Michael. "Laser development and stabilization for the spaceborne interferometric gravitational wave detector LISA." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974983705.
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Oppermann, Patrick [Verfasser]. "Characterization and stabilization of a high power fiber amplifier laser / Patrick Oppermann." Hannover : Technische Informationsbibliothek (TIB), 2017. http://d-nb.info/1136882707/34.
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Rollins, Jameson Graef 1976. "Intensity stabilization of a solid-state laser for interferometric gravitational wave detectors." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/29368.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Physics, 2004.Includes bibliographical references (p. 69-71).
A high-power, low noise photo-detector, in conjunction with a current shunt actuator has been used in an AC-coupled servo to stabilize the intensity of a 10 Watt continuous-wave Nd:YAG laser. A relative intensity noise of 1 x 10⁻⁸ [square root] Hz at 10 Hz has been achieved.
by Jameson Graef Rollins.
S.M.
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Moon, Eric Wayne. "Carrier-envelope phase stabilization of grating-based chirped-pulse amplifiers." Diss., Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1125.
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Thorin, Emil. "Towards the carrier-envelope phase stabilization of a16 TW 4.5 fs laser system." Thesis, Umeå universitet, Institutionen för fysik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-152443.
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In the last decades the scientific development has made it possible to produce pulses with durations below the femtosecond time scale (1 fs = 1015 s), reaching to attoseconds (1 as = 1018 s). This is the time scale of electronic motion inside atoms and molecules. One way to produce isolated attosecond pulses is through high harmonic generation in gases with intense few-cycle laser pulses. This process depends strongly on the electric field shape relative to the pulse envelope, which is characterized by the so called carrier-envelope phase (CEP).The goal of this master’s thesis is to measure and investigate the possibility to improve the CEP stability of sub-two-cycle laser pulses from the laser, Light Wave Synthesizer 20 (LWS-20). The first step of the master’s thesis was to modify a Labview program used to evaluate the CEP change to be able to reevaluate the already acquired raw data. The measurements are done with an f-to-2f interferometer, whichis a spectral interference device, which measures the CEP difference between two pulses. The CEP change of the laser system was measured at three positions: after the multi-pass amplifier of the laser front end (MP), after a hollow-core fiber (HCF), which is used for spectral broadening, and at the end of the laser system. The stability is determined as the RMS error (standard deviation) of the phase change overall shots in one sample (lower RMS is better stability). The measurements show an average stability of 160±20 mrad RMS after the MP, 280±31 mrad RMS after the HCF and 560±53 mrad RMS at the end of the system. The stability at the end of the system could be improved to 475±40 mrad RMS after a scan of the pump energy for one of the amplifier stages. The HCF appears to provide a lower limit in stability and influences it only if it is very good after the MP. The alignment of the HCF does also seem to influence the CEP stability and the best stability appears to coincide with maximum output energy. An acousto-optic modulator (Dazzler) has been used to manipulate the CEP change at the end of the system and can thereby compensate for long-term drifts, but the source of the CEP stability degradation at the end of the system should be further investigated.
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Guionie, Marie. "Lasers à fibres bifréquences bipolarisations : stabilisation et montée en fréquence du battement." Thesis, Rennes 1, 2020. http://www.theses.fr/2020REN1S059.
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Cette étude porte sur les lasers à fibres bifréquences bipolarisations. Le contrôle de la différence de fréquence de ces lasers représente un enjeu important en photonique microonde. En effet, maîtriser le battement permettrait la réalisation de sources compactes et à faible bruit visant des applications de métrologie ou télécom. Nous travaillons ici sur des sources émettant à 1,5 μm, de type DFB ou DBR, soit dopés Er soit co-dopés Er-Yb. Ils présentent une fréquence de battement d'environ 1 GHz pour les DFB, et 100 MHz pour les DBR. Les objectifs de la thèse ont été, d'abord de stabiliser le battement, puis d'explorer différentes méthodes pour modifier la biréfringence de la fibre et ainsi accroître la fréquence de battement. Nous avons d'abord utilisé la méthode de stabilisation par boucle à verrouillage de phase pour asservir le battement sur une fréquence de référence. En nous servant de la diode de pompe comme actuateur, nous avons réussi à stabiliser des battements entre 300 MHz et 10 GHz pendant plusieurs jours. Ensuite, nous avons mis en place une méthode de stabilisation par réinjection optique décalée en fréquence. Un modèle théorique basé sur des équations-bilan couplées a été utilisé et a permis de retrouver les observations expérimentales. En stabilisant le battement sur une référence extérieure, différents régimes dynamiques ont été observés. Dans la zone stable, on réduit le bruit de phase jusqu'à −100 dBc/Hz à 1 kHz de la porteuse. Puis, nous avons couplé le montage de la réinjection optique a une ligne à retard, afin de stabiliser efficacement le battement sur lui-même. Enfin, nous avons étudié plusieurs pistes pour augmenter la fréquence de battement des lasers DBR pour répondre aux besoins des applications. Nous avons pu suivre en temps réel la modification de biréfringence photo-induite par un faisceau UV. Nous avons aussi étudié une méthode de modification réversible de la biréfringence, en exploitant l'effet élasto-optique. Quelque soit la méthode employée, nous avons observé un accroissement de la fréquence de battement depuis 100 MHz jusqu'à plus de 10 GHz dans le meilleur des casThis work is about dual-polarization dual-frequency fibers lasers. The control of the frequency difference of these lasers is a major challenge in microwave photonics. Controlling the beat frequency could allow compact and low-noise sources, in order to develop applications in metrology or telecom. Here, we focus on 1.5 μm sources, in either DFB or DBR configurations, made of Er-doped or co-doped Er:Yb silica fibres. Their beat frequency is about 1 GHz for DFB lasers, and 100 MHz for DBR lasers. This thesis investigates several methods to stabilize the beat note, then to modify the fiber birefringence, to increase the beat frequency. First, an optical phase-locked loop method is used to lock the beat note on a frequency reference. By using the pump diode as an actuator, we have successfully stabilized beat frequencies between 300 MHz and 10 GHz for days. We then study a stabilization method by frequency-shifted optical feedback. A theoretical model based on rate equations model is used and allows to retrieve the experimental observations. We observe different dynamical regimes by locking the beat note on a reference frequency. In the stable area, we reduce the phase noise to −100 dBc/Hz at 1 kHz from the carrier. Next, we have mixed the set-up of the injection-locking to a delay line, in order to effectively stabilize the beat note on itself. Finally, various approaches have been explored to increase the beat frequency of DBR lasers, to the needs of applications. It has been possible to continuously monitor the impact of a UV beam on the fiber birefringence. We also studied a method for reversible modification of the birefringence, exploiting the elasto-optical effect. Regardless of the method used, we observed an increase in the beat frequency from 100 MHz to more than 10 GHz in the best case
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Quinlan, Franklyn. "LOW NOISE, HIGH REPETITION RATE SEMICONDUCTOR-BASED MODE-LOCKED LASERS FOR SIGNAL PROCESSING AND COHERENT COMMUNICATIONS." Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3393.
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This dissertation details work on high repetition rate semiconductor mode-locked lasers. The qualities of stable pulse trains and stable optical frequency content are the focus of the work performed. First, applications of such lasers are reviewed with particular attention to applications only realizable with laser performance such as presented in this dissertation. Sources of timing jitter are also reviewed, as are techniques by which the timing jitter of a 10 GHz optical pulse train may be measured. Experimental results begin with an exploration of the consequences on the timing and amplitude jitter of the phase noise of an RF source used for mode-locking. These results lead to an ultralow timing jitter source, with 30 fs of timing jitter (1 Hz to 5 GHz, extrapolated). The focus of the work then shifts to generating a stabilized optical frequency comb. The first technique to generating the frequency comb is through optical injection. It is shown that not only can injection locking stabilize a mode-locked laser to the injection seed, but linewidth narrowing, timing jitter reduction and suppression of superfluous optical supermodes of a harmonically mode-locked laser also result. A scheme by which optical injection locking can be maintained long term is also proposed. Results on using an intracavity etalon for supermode suppression and optical frequency stabilization then follow. An etalon-based actively mode-locked laser is shown to have a timing jitter of only 20 fs (1Hz-5 GHz, extrapolated), optical linewidths below 10 kHz and optical frequency instabilities less than 400 kHz. By adding dispersion compensating fiber, the optical spectrum was broadened to 2 THz and 800 fs duration pulses were obtained. By using the etalon-based actively mode-locked laser as a basis, a completely self-contained frequency stabilized coupled optoelectronic oscillator was built and characterized. By simultaneously stabilizing the optical frequencies and the pulse repetition rate to the etalon, a 10 GHz comb source centered at 1550 nm was realized. This system maintains the high quality performance of the actively mode-locked laser while significantly reducing the size weight and power consumption of the system. This system also has the potential for outperforming the actively mode-locked laser by increasing the finesse and stability of the intracavity etalon. The final chapter of this dissertation outlines the future work on the etalon-based coupled optoelectronic oscillator, including the incorporation of a higher finesse, more stable etalon and active phase noise suppression of the RF signal. Two appendices give details on phase noise measurements that incorporate carrier suppression and the noise model for the coupled optoelectronic oscillator.Ph.D.
Optics and Photonics
Optics and Photonics
Optics PhD
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Bouchard, Line. "Stabilization of an FM active harmonic mode-locked fiber laser at high repetition rates." Thesis, University of Ottawa (Canada), 2005. http://hdl.handle.net/10393/27614.
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A new and simple approach was optimized for stabilizing a harmonic active mode-locked fiber laser at 40GHz. A computer tunes the modulation frequency in a 500kHz band near 40GHz to follow variations in the optical cavity length. A second approach based on a Proportional-Integral ( PI) controller and a piezo fiber stretcher was also developed and optimized. This approach uses a circuit-controlled piezo (PZT) device to physically counteract optical cavity length variations.
The optimized circuit-controlled and computer-controlled approaches were compared to draw conclusions on their performance. Results for the pulse characteristics, the side mode suppression ratio and the time jitter show that both approaches provide an efficient method for stabilizing a harmonic FM active mode-locked fiber laser at 40GHz. Finally, the versatility of both approaches was used to attempt to generalize the two methods for use at any modulation frequency up to 40GHz.
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Lally, Evan M. "A Narrow-Linewidth Laser at 1550 nm Using the Pound-Drever-Hall Stabilization Technique." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/34739.
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Linewidth is a measure of the frequency stability of any kind of oscillator, and it is a defining characteristic of coherent lasers. Narrow linewidth laser technology, particularly in the field of fiber-based infrared lasers, has progressed to the point where highly stable sources are commercially available with linewidths on the order of 1-100 kHz. In order to achieve a higher level of stability, the laser must be augmented by an external frequency stabilization system.
This paper presents the design and operation of a frequency locking system for infrared fiber lasers. Using the Pound-Drever-Hall technique, the system significantly reduces the linewidth of an input laser with an un-stabilized linewidth of 2 kHz. It uses a high-finesse Fabry-Perot cavity, which is mechanically and thermally isolated, as a frequency reference to measure the time-varying frequency of the input laser. An electronic feedback loop works to correct the frequency error and maintain constant optical power. Testing has proven the Pound-Drever-Hall system to be highly stable and capable of operating continuously for several seconds at a time.Master of Science
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Mandre, Shyam K. "Controlling the emission properties of high power semiconductor lasers stabilization by optical feedback and coherence control." Berlin Logos-Verl, 2006. http://deposit.d-nb.de/cgi-bin/dokserv?id=2833481&prov=M&dok_var=1&dok_ext=htm.
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Ayling, Neroli Kim. "Organometallics in the Stabilization of Dyed Fibres." Thesis, University of Canterbury. Chemistry, 2008. http://hdl.handle.net/10092/1693.
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It has been observed that in certain cases the exposure of dyed fibres to aging techniques results in the strengthening of fibres. This thesis explores the hypothesis that the strengthening is due to radical cross-coupling reactions that could be initiated through metal ion mediated photodecarboxylation. The approaches taken in this research include kinetic experiments (using flash photolysis), examination of possible cross-coupling experiments (using species of opposite charge), and the design and examination of small molecule model systems. A flash photolysis system was developed and used in attempts to determine the rates of photochemical product formation for cobalt(III) amino acid complexes. Lower limits have been established for the rate of product formation in these systems. The lower limits are: 2 x 10⁷ s⁻¹ for [Co(bpy)2(gly)]²⁺; 2 x 10⁷ s⁻¹ for [Co(tpa)(gly)]²⁺; and 5 x 10⁶ s⁻¹ for [Co(tpa)(aib)]²⁺, where bpy is 2,2'-bipyridine; gly is glycinate; tpa is tris(2-pyridylmethyl)amine; and aib is aminoisobutyrate. In past studies, the rates of a series of cobalt(III) amino acid complexes were reported as being the same, and much slower. It is thought that in these cases it may not be the rate of the formation of product that was being measured, but rather the response time of the electronics that was being observed. In this thesis the results obtained for the rate for the aib complex were somewhat lower than those of the gly complexes. This may imply, for the aib complex at least, the rate of the formation of the metallocycle is being observed (and not the response times of the electronics or other limitations of the instrumentation), but the data is poor and there is considerable doubt about this. The steady state photolysis of opposite charged species [Co(bpy)2(gly)]²⁺ and [Co(EDTA)]⁻ is reported. The reactions were carried out on a small scale in deuterated solvent for NMR spectrometry analysis and also on a large scale for the possible isolation and characterisation of the products. Evidence was found for a different reaction occurring when both complexes were present. The exact nature of the product remains elusive. A model system was designed in which a dinuclear ligand would bind to two metal centres and a fibre mimic would be later added. Eight ligands are discussed that could potentially bind two octahedral metal centres. They all had a xylene spacing group linking the two polydentate sites together. Five of the ligands have two bidentate binding sites. The other three had two tridentate sites. The binding sites in three of the bis(bidentate) ligands were based on ethane-1,2- diamine (en). Two of these ligands produced hypodentate monocobalt and sundentate dicobalt complexes. The other two bidentate ligands were based on 2- aminomethylpyridine (ampy). Both of these ligands degraded in the complexation reaction conditions. The binding sites in the tridentate ligands were all based on tacn. Once again, the principal products isolated were hypodentate systems in which only one metal ion was coordinated by the ligands. There is a distinct pattern observed in the xylene spaced ligands to form hypodentate complexes with cobalt(III) metal centred complexes. There is evidence of the di-nuclear species from a reaction with a charcoal catalyst in the bis(bidentate) system. ¹H NMR spectrometry, ¹³C NMR spectrometry, elemental analysis, X-ray crystallography and UV-vis spectroscopy were used to study and characterise the complexes and ligands that were prepared in this project.
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Ebadi, Hossein [Verfasser], and Christoph H. [Akademischer Betreuer] Keitel. "Stabilization and interference in high-frequency laser driven atoms / Hossein Ebadi ; Betreuer: Christoph H. Keitel." Heidelberg : Universitätsbibliothek Heidelberg, 2011. http://d-nb.info/1179228898/34.
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Wu, Shun. "Direct fiber laser frequency comb stabilization via single tooth saturated absorption spectroscopy in hollow-core fiber." Diss., Kansas State University, 2014. http://hdl.handle.net/2097/18373.
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Doctor of PhilosophyDepartment of Physics
Kristan L. Corwin
Portable frequency references are crucial for many practical on-site applications, for example, the Global Position System (GPS) navigation, optical communications, and remote sensing. Fiber laser optical frequency combs are a strong candidate for portable reference systems. However, the conventional way of locking the comb repetition rate, frep, to an RF reference leads to large multiplied RF instabilities in the optical frequency domain. By stabilizing a comb directly to an optical reference, the comb stability can potentially be enhanced by four orders of magnitude. The main goal of this thesis is to develop techniques for directly referencing optical frequency combs to optical references toward an all-fiber geometry. A big challenge for direct fiber comb spectroscopy is the low comb power. With an 89 MHz fiber ring laser, we are able to optically amplify a single comb tooth from nW to mW (by a factor of 10^6) by building multiple filtering and amplification stages, while preserving the comb signal-to-noise ratio. This amplified comb tooth is directly stabilized to an optical transition of acetylene at ~ 1539.4 nm via a saturated absorption technique, while the carrier-envelope offset frequency, f0, is locked to an RF reference. The comb stability is studied by comparing to a single wavelength (or CW) reference at 1532.8 nm. Our result shows a short term instability of 6 x10^(-12) at 100 ms gate time, which is over an order of magnitude better than that of a GPS-disciplined Rb clock. This implies that our optically-referenced comb is a suitable candidate for a high precision portable reference. In addition, the direct comb spectroscopy technique we have developed opens many new possibilities in precision spectroscopy for low power, low repetition rate fiber lasers. For single tooth isolation, a novel cross-VIPA (cross-virtually imaged phase array) spectrometer is proposed, with a high spectral resolution of 730 MHz based on our simulations. In addition, the noise dynamics for a free space Cr:forsterite-laser-based frequency comb are explored, to explain the significant f0 linewidth narrowing with knife insertion into the intracavity beam. A theoretical model is used to interpret this f0 narrowing phenomenon, but some unanswered questions still remain.
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SANTAGATA, ROSA. "Sub-nanometer length metrology for ultra-stable ring laser gyroscopes." Doctoral thesis, Rosa Santagata, 2015. http://hdl.handle.net/11365/1004514.
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Large-frame ring laser gyroscopes are extremely sensitive inertial detectors of rotational motion. When properly coupled to the ground, they provide precise measurements of the Earth rotation rate and give important informations to geodesy and geophysics. Recent advances in this technology led to consider the application of ring laser gyroscopes to fundamental physics. In this context is GINGER (Gyroscopes IN GEneral Relativity), a scientic proposal for testing General Relativity (local observation of the Lense-Thirring eect) with a ground-based array of ring laser gyroscopes. The experimental target is to locally measure the Earth rotation rate with a relative precision better than one part in 109, corresponding to an absolute rotational resolution of 10−14 rad/s. The main factor limiting the performances of the presently most stable ring laser gyroscopes is the uncontrolled deformation of their optical cavity, since instabilities in the cavity geometry introduce systematic errors in the rotational signal. Cavity geometry is typically kept stable by using monolithic frames made of ultra-low thermal expansion materials, and operating in very well isolated environments. An alternative approach is based on the active control of the shape in heterolithic cavities, by measuring and stabilizing the mirrors positions by means of laser-based length metrology.
The goal of this thesis is the development of a stabilization system based on interferometric length metrology, with a view to improve the sensitivity of the new generation square ring laser gyroscopes, going beyond the level achievable with passive methods. The main idea proposed in this work is to exploit the diagonal resonators formed by opposite cavity mirrors, and to use their lengths as observables to constraint, against an optical reference standard, residual deformation degrees of freedom of the square cavity.
As a rst step, a detailed model of the light propagation along the square cavity has been developed. This allowed us to quantify the eectiveness of the
v
xed length constraint of the diagonal resonators, and gave precise indications for the optimization strategy of the residual degrees of freedom.
The optical frequency reference is a helium neon laser stabilized to the iodine molecular absorption. Since the power emitted by this laser is of only 300 µW, an optical amplier, based on the injection locking of a 15 mW diode laser, has been developed to guarantee a proper signal to noise ratio in the interferometric absolute length measurements.
To stabilize the absolute lengths of the two diagonals, we proposed an original experimental method for the determination of both the optical resonance frequency and the free spectral range of each cavity. It is based on a triple-frequency modulation of the interrogating laser beam by electro-optic modulators. In a rst tabletop experiment, the method has been veried on two Fabry-Perot resonators that, composed by couples of spherical mirrors typically used in the He-Ne ring cavities, simulate the diagonals of a ring laser gyroscope on an optical bench. Here, the capability of setting equal the two lengths at the level of 500 nm, with residual uctuations only limited by the laser frequency noise, has been experimentally proved.
As a nal result, we have applied the developed method to lock the diagonal cavities lengths of GP2 ring laser gyroscope, a square cavity 1.6 m in side length dedicated to the interferometric control of the cavity geometry deformations, and fully set up at the INFN laboratories in Pisa in June 2015
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Xavier, Pradip. "Investigation of flame stabilization mechanisms in a premixed combustor using a hot gas cavity-based flame holder." Thesis, Rouen, INSA, 2014. http://www.theses.fr/2014ISAM0016/document.
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Cette thèse décrit l'étude d'une chambre de combustion innovante de type Trapped Vortex Combustor (TVC): ce concept utilise des cavités de gaz chauds pour stabiliser des flammes prémélangées pauvres. A partir d'une étude globale d'un point de fonctionnement instable, l'approche scientifique vise à différencier l'impact des différents mécanismes physiques. La structure de l'écoulement inerte est étudiée finement avant de mener une étude spatio-Temporelle sur un point de fonctionnement instable, en conditions réactives. L'analyse permet de comprendre les interactions entre la structure de la flamme, la topologie de l'écoulement et l'acoustique du brûleur. Différents mécanismes pilotant l'apparition d'instabilités de combustion sont mis en évidence, et des recommandations sont fournies afin de les supprimer. Un vérification a posteriori permet de valider l'importance de ces mécanismes, notamment grâce à la détermination de diagrammes de stabilité de flammeThis thesis describes the investigation of an innovative trapped vortex combustor (TVC): this concept uses recirculating hot gas flow trapped in cavities to stabilize lean main flames. Based on a global investigation of an unstable operating condition, the scientific strategy aims to treat separately the different physical mechanisms. The inert flow structure is analyzed prior to leading a spatio-Temporal study on an unstable mode. This investigation aims to understand the flaine-Flow-Acoustic interactions in the combustor. Several mechanisms piloting combustion instabilities are highlighted, and recommandations are provided in order to suppress them. An a posteriori check validate the preponderance of these mechanisms, in particular with the determination of stability flaine diagrams
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Ikram, Masroor. "Investigations in carbon dioxide laser stabilization and saturation spectroscopy using the Stark effect and acousto-optic modulation." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335729.
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Padgett, Miles John. "Techniques for ultra-high resolution saturation spectroscopy and laser stabilization in the 10#mu#m spectral region." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305843.
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Dawkins, Samuel T. "Sapphire room temperature optical frequency reference : design, construction and application." University of Western Australia. School of Physics, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0200.
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A pair of high-stability optical frequency references has been developed. The devices are based on room temperature Fabry-Perot cavities with mirrors spaced apart by a hollow single-crystal sapphire element. The sapphire element delivers mechanical sti ness that provides improved immunity to vibrational perturbations compared with the more common spacers made from ultra-low expansion glass. The system is housed in an vacuum chamber designed to provide isolation from environmental perturbations through the use of an active thermal control system, suspension legs and a unique beam alignment system. The dimensional stability of the Fabry-Perot was translated into a highly stable laser frequency by frequency locking a 1064nm Nd:YAG laser to the centre of a mode of the cavity. This frequency lock was implemented by the Pound-Drever-Hall scheme. By careful design, this control system was able to hold the frequency of the laser to within parts in 1016 of the frequency of the fundamental cavity mode. The minimum fractional frequency stability of the laser frequency was measured at 2.1x10[-]14 for integration times of 0.8 s, limited by the residual instability of the Fabry-Perot cavity. The experimental methods used to measure the performance of the system have also been considered in depth. For example, the most common way of characterizing the frequency stability of a frequency standard is the Allan variance. It is demonstrated that, without care, data taken with modern frequency counters can produce erroneous and distorted results when their output is supplied to this algorithm. The method to avoid or account for these errors is also presented. The Fabry-Perot cavity performance is limited on long timescales by residual temperature uctuations, which can be ameliorated in future by enhancing the design of the thermal control system. At short timescales, the system is limited by vibration-induced uctuations together with a white noise source, that is yet to be identi ed, but may relate to fundamental thermodynamic temperature uctuations of the sapphire spacer. This system was used to measure the stability of an optical signal synthesised from a cryogenic microwave sapphire oscillator using an wide-band optical frequency comb. This was the rst demonstration of a multiplication of an ultra-stable signal from the microwave frequency domain into the optical frequency domain, without loss of delity at the level of 2x10[-]14.
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Parslow, David. "A study of intra-cavity optoacoustic signal generation in a CO2 waveguide laser and its application to frequency stabilization." Thesis, Keele University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358042.
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Grib, Stephen William. "LAMINAR AND TURBULENT STUDY OF COMBUSTION IN STRATIFIED ENVIRONMENTS USING LASER BASED MEASUREMENTS." UKnowledge, 2018. https://uknowledge.uky.edu/me_etds/117.
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Practical gas turbine engine combustors create extremely non-uniform flowfields, which are highly stratified making it imperative that similar environments are well understood. Laser diagnostics were utilized in a variety of stratified environments, which led to temperature or chemical composition gradients, to better understand autoignition, extinction, and flame stability behavior. This work ranged from laminar and steady flames to turbulent flame studies in which time resolved measurements were used.
Edge flames, formed in the presence of species stratification, were studied by first developing a simple measurement technique which is capable of estimating an important quantity for edge flames, the advective heat flux, using only velocity measurements. Both hydroxyl planar laser induced fluorescence (OH PLIF) and particle image velocimetry (PIV) were used along with numerical simulations in the development of this technique. Interacting triple flames were also created in a laboratory scale burner producing a laminar and steady flowfield with symmetric equivalence ratio gradients. Studies were conducted in order to characterize and model the propagation speed as a function of the flame base curvature and separation distance between the neighboring flames. OH PLIF, PIV and Rayleigh scattering measurements were used in order to characterize the propagation speed. A model was developed which is capable of accurately representing the propagation speed for three different fuels. Negative edge flames were first studied by developing a one-dimensional model capable of reproducing the energy equation along the stoichiometric line, which was dependent on different boundary conditions. Unsteady and laminar negative edge flames were also simulated with periodic boundary conditions in order to assess the difference between the steady and unsteady cases. The diffusive heat loss was unbalanced with the chemical heat release and advective heat flux energy gain terms which led to the flame proceeding and receding. The temporal derivative balanced the energy equation, but also aided in the understanding of negative edge flame speeds. Turbulent negative edge flame velocities were measured for extinguishing flames in a separate experiment as a function of the bulk advective heat flux through the edge and turbulence level. A burner was designed and built for this study which created statistically stationary negative edge flames. The edge velocity was dependent on both the bulk advective heat flux and turbulence levels. The negative edge flame velocities were obtained with high speed stereo-view chemiluminescence and two dimensional PIV measurements.
Autoignition stabilization was studied in the presence of both temperature and species stratification, using a simple laminar flowfield. OH and CH2O PLIF measurements showed autoignition characteristics ahead of the flame base. Numerical chemical and flow simulations also revealed lower temperature chemistry characteristics ahead of the flame base leading to the conclusion of lower temperature chemistry dominating the stabilization behavior. An energy budget analysis was conducted which described the stabilization behavior.
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Golinelli, Anna. "Development of an original 10 kHz Ti : Sa regenerative cavity allowing 17 fs CEP stable 1 kHz TW-class amplification or wavelength tunability." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS018.
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Au cours de dix dernières années la science aux attoseconde ou Physique au champ-fort a été l’objet d’un fort développement. La production d’impulsions laser énergétiques de courte durée à haute cadence et stabilisées en CEP constitue la première étape pour accéder aux dynamiques ultra-rapides caractérisant l’interaction de la matière avec une source de lumière cohérente, intense et ultra-rapide. Le travail de cette thèse consiste à améliorer globalement les performances d’un système laser Ti:Sa à haute cadence optimisé pour la génération des impulsions attoseconde. Nous avons développé une nouvelle configuration de cavité régénérative fonctionnant à 10 kHz qui permet une meilleure gestion des effets thermiques dans le cristal. En sortie de l’amplificateur les impulsions atteignent des valeurs de puissance de 5 W en bande étroite (35 fs), ou 2.7 W en bande spectrale large permettant une compression des impulsions proche de 17 fs. La CEP des impulsions en sortie d’amplificateur a été stabilisée ; le bruit résiduel mesuré tir-à-tir est de 210 mrad pendant trois heures.L’amplificateur peut supporter également le fonctionnement en mode accordable, en sélectionnant des spectres de 30 à 40 nm de largeur à mi-hauteur et en accordant leur longueur d’onde centrale dans une gamme de 80 nm autour de 800 nm. Nous avons conçu et mis en fonctionnement un amplificateur multi-passages non-cryogéné à imagerie par lentille thermique pour accroître la puissance des impulsions jusqu’à 10 W à une cadence de 1 kHz. Le régime de forte saturation d’amplificateur garantit une variation négligeable (±3% pic à pic) de la puissance des impulsions en sortie du module, face à une variation importante de la puissance en entrée (±25% pic à pic) sur la bande spectrale accordable. L’amplification peut encore être plus importante grâce à une ligne d’amplification à refroidissement cryogénique, qui permet d’atteindre des puissances au niveau TW, à la cadence de 1 kHz, tout en maintenant un régime de courte durée (17.5 fs) et stabilité en CEP (350 mrad de bruit résiduel tir-à-tir). Nous proposons aussi une étude des sources de bruit de CEP dans les modules hautement dispersifs: nous avons conçu une nouvelle approche numérique sur la base d’un logiciel de tracé de rayon commercial (Zemax) pour évaluer les variations de CEP dans les modules contenant réseaux de diffractionThe last decade has seen a lot of progress in attosecond science or in strong field physics. Generating energetic, few-cycle laser pulses with stabilized Carrier-Envelope Phase at high repetition rate constitutes the first step to access the ultra-fast dynamics underlying the interaction of matter with intense, ultrashort coherent light source. The work of this thesis consists in globally improving the performances of a high repetition rate Ti:Sa laser system optimized for attosecond science. We present an original 10 kHz Ti:Sa CPA laser based on an newlydesigneddouble-crystal cavity for thermal lensing management. The amplifier delivers up to 5 W in narrow band mode (35 fs pulses), or 2.7 W in broad band mode, supporting 17 fs pulses after temporal compression. We demonstrate shot-to-shot CEP stabilization with a remaining noise of 210 mrad over three hours at the front-end output. In parallel to the short pulse duration operation mode, it is possible to use the front end in a wavelength tunability mode within a 80 nm range around 800 nm, with a resolution of 1 nm and 30 to 40 nm of bandwidth. We designed and demonstrated a complete water-cooled lens-less multipass amplifier using thermal lensing for modeadaptation boosting the pulse energy up to 10mJ at 1 kHz repetition rate (up to 10 W). The saturation regime of the amplifier ensures negligible variation (±3% peak to peak) of the output power for significant variation of the input power (±25% peak to peak) over the tunability range. The energy scalability of the front-end is demonstrated by coupling its output to cryogenically cooled amplifier, delivering 1 kHz, TW-class pulses at 17.5 fs and CEP stabilized with a residual noise of 350 mrad. A study of CEP noise sources in high dispersive module is also addressed, proposing a numerical approach based on a commercial ray-tracing software (Zemax) for predicting CEP fluctuation in grating based modules
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Lamb, Thorsten [Verfasser], and ERNST [Akademischer Betreuer] BRINKMEYER. "Laser-to-RF phase detection with femtosecond precision for remote reference phase stabilization in particle accelerators / Thorsten Lamb ; Betreuer: Ernst Brinkmeyer." Hamburg : Universitätsbibliothek der Technischen Universität Hamburg-Harburg, 2017. http://d-nb.info/1133581595/34.
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Borchers, Bastian Verfasser], Thomas [Akademischer Betreuer] Elsässer, Kurt [Akademischer Betreuer] Busch, and Franz X. [Akademischer Betreuer] [Kärtner. "Pushing frontiers in Carrier-Envelope Phase stabilization of ultrashort laser pulses / Bastian Borchers. Gutachter: Thomas Elsässer ; Kurt Busch ; Franz X. Kärtner." Berlin : Mathematisch-Naturwissenschaftliche Fakultät, 2015. http://d-nb.info/1067484930/34.
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Borchers, Bastian [Verfasser], Thomas Akademischer Betreuer] Elsässer, Kurt [Akademischer Betreuer] Busch, and Franz X. [Akademischer Betreuer] [Kärtner. "Pushing frontiers in Carrier-Envelope Phase stabilization of ultrashort laser pulses / Bastian Borchers. Gutachter: Thomas Elsässer ; Kurt Busch ; Franz X. Kärtner." Berlin : Mathematisch-Naturwissenschaftliche Fakultät, 2015. http://nbn-resolving.de/urn:nbn:de:kobv:11-100226662.
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Lamb, Thorsten [Verfasser], and Ernst [Akademischer Betreuer] Brinkmeyer. "Laser-to-RF phase detection with femtosecond precision for remote reference phase stabilization in particle accelerators / Thorsten Lamb ; Betreuer: Ernst Brinkmeyer." Hamburg : Universitätsbibliothek der Technischen Universität Hamburg-Harburg, 2017. http://d-nb.info/1133581595/34.
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Sands, Brian L. "Characteristics and dynamics of a passively stabilized high power and narrow-bandwidth broad-area laser coupled to an external variable length cavity." Connect to this document online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1122662023.
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Thesis (M.S.)--Miami University, Dept. of Physics, 2005.Title from first page of PDF document. Document formatted into pages; contains [1], ix, 93 p. : ill. Includes bibliographical references (p. 88-93).
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Schmidt, Florian. "Laser-based Absorption Spectrometry : Development of NICE-OHMS Towards Ultra-sensitive Trace Species Detection." Doctoral thesis, Umeå : Department of Physics, Umeå Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1414.
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Soni, Abhishek. "Experimental Investigation of Flame Aerodynamics for Confined and Unconfined Flow for a Novel Radial-Radial Novel Injector using 2D Laser Doppler Velocimetry." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1552656922178471.
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Foltynowicz, Aleksandra. "Fiber-laser-based noise-immune cavity-enhanced optical heterodyne molecular spectrometry." Doctoral thesis, Umeå universitet, Institutionen för fysik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-22269.
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Noise-immune cavity-enhanced optical heterodyne molecular spectro-metry (NICE-OHMS) is one of the most sensitive laser-based absorption techniques. The high sensitivity of NICE-OHMS is obtained by a unique combination of cavity enhancement (for increased interaction length with a sample) with frequency modulation spectrometry (for reduction of noise). Moreover, sub-Doppler detection is possible due to the presence of high intensity counter-propagating waves inside an external resonator, which provides an excellent spectral selectivity. The high sensitivity and selectivity make NICE-OHMS particularly suitable for trace gas detection. Despite this, the technique has so far not been often used for practical applications due to its technical complexity, originating primarily from the requirement of an active stabilization of the laser frequency to a cavity mode. The main aim of the work presented in this thesis has been to develop a simpler and more robust NICE-OHMS instrumentation without compro-mising the high sensitivity and selectivity of the technique. A compact NICE-OHMS setup based on a fiber laser and a fiber-coupled electro-optic modulator has been constructed. The main advantage of the fiber laser is its narrow free-running linewidth, which significantly simplifies the frequency stabilization procedure. It has been demonstrated, using acetylene and carbon dioxide as pilot species, that the system is capable of detecting relative absorption down to 3 × 10-9 on a Doppler-broadened transition, and sub-Doppler optical phase shift down to 1.6 × 10-10, the latter corresponding to a detection limit of 1 × 10-12 atm of C2H2. Moreover, the potential of dual frequency modulation dispersion spectrometry (DFM-DS), an integral part of NICE-OHMS, for concentration measurements has been assessed. This thesis contributes also to the theoretical description of Doppler-broadened and sub-Doppler NICE-OHMS signals, as well as DFM-DS signals. It has been shown that the concentration of an analyte can be deduced from a Doppler-broadened NICE-OHMS signal detected at an arbitrary and unknown detection phase, provided that a fit of the theoretical lineshape to the experimental data is performed. The influence of optical saturation on Doppler-broadened NICE-OHMS signals has been described theoretically and demonstrated experimentally. In particular, it has been shown that the Doppler-broadened dispersion signal is unaffected by optical saturation in the Doppler limit. An expression for the sub-Doppler optical phase shift, valid for high degrees of saturation, has been derived and verified experimentally up to degrees of saturation of 100.
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Natile, Michele. "High-repetition rate CEP-stable Yb-doped fiber amplifier for high harmonic generation." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS149.
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Depuis une vingtaine d’années, la physique attoseconde, via le phénomène de génération d’harmoniques d’ordres élevés (HHG), a permis de nombreuses avancées dans la compréhension des phénomènes de dynamique ultra-rapide. Les lasers femtoseconde émettant des impulsions de fortes énergies et de durées de quelques cycles optiques sont les outils indispensables à cette physique. De plus, la phase entre la porteuse et l’enveloppe (CEP) des impulsions doit être contrôlée. Récemment les lasers basés sur les fibres dopées ytterbium ont permis de transposer les expériences d’HHG à haute cadence. La stabilisation de la CEP pour ce type de systèmes constitue la brique manquante au développement de sources à haute cadence pleinement compatibles avec ces applications. Cette thèse a été consacrée à la stabilisation CEP d’un laser à fibre dopée ytterbium pour une application à la génération de rayonnement cohérent dans l’XUV à fort flux de photon. Dans la première partie nous présentons l’architecture d’une source à un taux de répétition de 100 kHz stable en CEP émettant des impulsions de 30 microjoules et 96 fs. Ce système constitue une preuve de principe pour les futures sources haute énergie. La stabilisation de CEP est assurée par une architecture hybride composée d’un injecteur stabilisé passivement suivi d’un amplificateur de puissance stabilisé activement. Un bruit résiduel de CEP inférieur à 400 mrad est obtenu dans différentes configurations, de la mesure courte durée (1 s) tir à tir jusqu’à la mesure sur une heure de fonctionnement. Dans la seconde partie nous présentons la mise au point d’une ligne HHG XUV optimisée à 13 nm sur les paramètres d’un laser à fibre, pour des applications à l’imagerie par diffraction cohérenteIn the last two decades, attosecond physics, based on the high harmonic generation (HHG) phenomenon, has allowed a better understanding of ultrafast dynamics in the microcosm. High-energy few-cycles carrier-envelope phase (CEP) stabilized sources are the main enabling tools for this physics. Recently, temporally compressed Ytterbium-doped fiber amplifiers have been successfully used as high XUV photon flux HHG drivers. CEP stabilization of these sources would ensure their full compatibility with attoscience. The thesis is devoted to the CEP stabilization of a high repetition rate Yb-doped fiber femtosecond source, for high XUV photon flux beamline applications. In the first part, we present the architecture of such a source at 100 kHz repetition rate delivering 30 microjoules 96 fs CEP-stable pulses. It constitutes a test bench for future energy-scaled few-cycle sources. The CEP stabilization is ensured in a hybrid architecture including a passively stabilized frontend followed by an actively stabilized power amplifier. A residual CEP noise <400 mrad is measured using various setups, including a shot-to-shot measurement over 1 s and a long-term stability over 1 h. In the second part, we discuss the design of a high flux HHG beamline optimized for a future generation of fiber-based driver at 13 nm for applications to coherent diffraction imaging
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Nillon, Julien. "Amplification paramétrique ultra-large bande dans l’ infrarouge en régime de forte énergie et de forte puissance moyenne." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14536/document.
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Alors que la science attoseconde connaît un développement fulgurant, le besoin de nouvelles sources laser adaptées à la génération d'impulsions attosecondes uniques est apparu. Grâce à ses propriétés d'accordabilité en fréquence et d'amplification de spectres ultra-larges à même de supporter des durées d'impulsions ultracourtes, conjuguées à la possibilité de stabiliser passivement la phase sous l'enveloppe (CEP) du champ électrique associé à l'impulsion laser, l'amplification paramétrique (OPA) s'est imposée comme un des outils incontournables pour la réalisation de telles sources.De plus, un intérêt croissant se manifeste pour la montée en cadence des sources d'harmoniques d'ordre élevé (HHG), en tirant parti des avancées des laser à fibre. Récemment fut démontrée la génération d'impulsions ultracourtes à très haute cadence, stabilisées en phase, dans la partie visible du spectre. Décaler la bande d'amplification vers l'infrarouge présenterait des avantages certains du point de vue de la génération d'harmoniques. En effet, travailler avec une source laser infrarouge permet d'étendre le spectre d'harmoniques et donc de réduire la durée des impulsions attosecondes générées. Jusqu'à présent, l'amplification paramétrique large bande dans l'infrarouge à haute cadence était rendue impossible par la difficulté à générer un signal à ces longueurs d'onde directement à partir d'un laser à fibre.Les travaux exposés ici décrivent la réalisation de nouvelles sources paramétriques, spécifiquement conçues en fonction des exigences de la génération d'impulsions attosecondes uniques, aussi bien en régime de forte énergie qu'à des cadences élevées.Nous présentons tout d'abord le développement d'un OPA avec stabilisation passive de la CEP, capable d'amplifier un spectre d'une largeur de 700 nm centré à 1,75 µm et délivrant une énergie de 450 µJ à la cadence de 10 Hz. Puis, nous détaillons une architecture originale d'amplification paramétrique à haute cadence pompé par un laser à fibre, qui nous a permis de générer des impulsions stabilisées en phase d'une durée inférieure à trois cycles optiques à la longueur d'onde centrale de 2,2 µm, avec une énergie de 5 µJ à la cadence de 100 kHz.Enfin, nous explorons la possibilité d'accroître la puissance de sortie des OPA infrarouges large bande à des niveaux de plusieurs dizaines de watts, grâce à la technique de combinaison paramétrique de plusieurs faisceaux de pompe fibrésWhile attosecond science reaches new frontiers in physics, the need for innovative primary sources suited for the generation of single attosecond (as) pulses emerges. Featuring high tunability, ultra-broadband amplification bandwidth and the ability of passively stabilizing the random Carrier-Envelope Phase (CEP) of any pump laser, Optical Parametric Amplification (OPA) has proven to be one of the most effective tools to meet the stringent requirements of High-Order Harmonics (HHG) driving sources.Moreover, there is a growing interest for higher repetition rate HHG sources, pumped by Ytterbium-doped fiber lasers. High-repetition rate, CEP-stable, few cycle pulses have been successfully generated by OPAs operating in the visible part of the spectrum. Shifting the amplified bandwidth towards longer wavelengths would be clearly profitable. In fact, the shorter harmonic wavelength cut-off will allow significantly extending the harmonics spectrum and consequently shorten as pulse durations. Until know, generation of CEP-stable, few-cycle pulses in the infrared at ultra-high repetition rates was impossible due to the issue of generating a broadband infrared seed directly from a fiber laser. This thesis describes the implementation of new supercontinuum-seeded parametric sources, specifically designed for isolated attosecond pulses generation with high energy or high repetition rate.The development of a CEP-stable three-stages OPA source is reported, amplifying a 700 nm broad spectrum at a central wavelength of 1,75 µm with an energy of 450 µJ at a 10 Hz repetition rate. Then, a new architecture based on a two-stage cascaded OPA pumped by a home-made fiber laser is presented, which allowed us to generate CEP-stable 3-cycles pulses at the central wavelength of 2,2 µm, with an energy of 5 µJ at 100 kHz. Finally, we discuss the possibility of increasing the output power of parametric amplifiers to several tens of watts with broadband parametric combination of several fiber-pump beams
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Turghun, Matniyaz. "Free-space NPR mode locked erbrium doped fiber laser based frequency comb for optical frequency measurement." Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/18682.
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Master of ScienceDepartment of Physics
Brian R. Washburn
This thesis reports our attempt towards achieving a phase stabilized free-space nonlinear polarization rotation (NPR) mode locked erbium doped fiber laser frequency comb system. Optical frequency combs generated by mode-locked femtosecond fiber lasers are vital tools for ultra-precision frequency metrology and molecular spectroscopy. However, the comb bandwidth and average output power become the two main limiting elements in the application of femtosecond optical frequency combs. We have specifically investigated the free-space mode locking dynamics of erbium-doped fiber (EDF) mode-locked ultrafast lasers via nonlinear polarization rotation (NPR) in the normal dispersion regime. To do so, we built a passively mode-locked fiber laser based on NPR with a repetition rate of 89 MHz producing an octave-spanning spectrum due to supercontinuum (SC) generation in highly nonlinear fiber (HNLF). Most significantly, we have achieved highly stable self-starting NPR mode-locked femtosecond fiber laser based frequency comb which has been running mode locked for the past one year without any need to redo the mode locking. By using the free-space NPR comb scheme, we have not only shortened the cavity length, but also have obtained 5 to 10 times higher output power (more than 30 mW at central wavelength of 1570 nm) and much broader spectral comb bandwidth (about 54 nm) compared to conventional all-fiber cavity structure with less than 1 mW average output power and only 10 nm spectral bandwidth. The pulse output from the NPR comb is amplified through a 1 m long EDF, then compressed by a length of anomalous dispersion fiber to a near transform limited pulse duration. The amplified transform limited pulse, with an average power of 180 mW and pulse duration of 70 fs, is used to generate a supercontinuum of 140 mW. SC generation via propagation in HNLF is optimized for specific polling period and heating temperature of PPLN crystal for SHG around 1030 nm. At last, we will also discuss the attempt of second harmonic generation (SHG) by quasi phase matching in the periodically polled lithium niobate (PPLN) crystal due to nonlinear effect corresponding to different polling period and heating temperature.
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SILVA, Cícero Moezio da. "Travamento da freqüência de um diodo laser nas asas da ressonância de uma linha atômica." Universidade Federal de Campina Grande, 2013. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1947.
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Capes
Este trabalho reporta o desenvolvimento experimental de um sistema de travamento da frequência de um diodo laser nas asas de uma linha atômica. Como sinal de erro, utilizamos a transmissão por uma célula com janelas paralelas (contendo vapor de césio) para o travamento da frequência. Mostramos que o sinal de erro é estável durante 1 hora e meia. Este sinal contemos citações nas asas da ressonância que podem ser usadas para a estabilização da frequência. Travamos a frequência entre 1860 a 2817 MHz fora da ressonância e obtemos uma estabilidade de 30MHz. A técnica descrita não necessita de campo magnético ou de detecção sensível a polarização,que simplifi ca substancialmente em relação às técnicas existentes.
In this work we demonstrate the experimental development of a system of frequency- locking of a diode laser on the wings of an atomic line. As an error signal, we use the transmission through a cell with parallel windows (containing cesium vapor) for the frequency-locking. We show that the error signalis stable for one hour and a half and has oscillations in the wings of the resonance that can be used tostabilize the frequency. We locked the frequency between 1860-2817 MHz out of resonance and obtained a stability of 30MHz. The described technique does not require a magnetic field or polarization-sensitive detection, whichs impli es substantially over existing techniques.
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Lyu, Jike. "Epitaxial Ferroelectric Thin Films on Si(001): strain tuning of BaTiO3 and stabilization of polar phase in Hf0.5Zr0.5O2." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667989.
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Hadef, Redjein. "Mesure du nombre de markstein pour une flamme de premelange plissee." Aix-Marseille 1, 1987. http://www.theses.fr/1987AIX11127.
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Etude de proprietes physico-chimiques d'une flamme plissee de propane, intrinsequement stable et se propageant librement vers le bas. Mesure de la vitesse de l'ecoulement en amont de la flammme et dans son voisinage, de l'amplitude et du rayon de courbure du front a l'aide de diagnostics optiques non intrusifs (anemometrie et tomographie laser, traitement de cliches photographiques)