Download or read book Diode Laser Diagnostics of Laser induced Plasmas and Atomic Vapor Cells written by Benoît Lauly and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Cesium atomic vapor filters or detectors have been a primary focus of this work as they demonstrate the potential to excel both in terms of spectral resolution and sensitivity. Atomic vapor detectors have a spectral resolution that is governed by the properties of the atomic vapor used as the sensing element, while maintaining the same value of the luminosity. Cesium vapor cells have been extensively investigated because of cesium's high number density at low temperature and its strong resonance transition in the near-infrared at 852nm (62S1/2 [if.then] 62P3/2). A promising fluorescence scheme for cesium has been demonstrated here that includes a single transition at 852nm and fluorescence detection at 894nm (62P1/2 [if.then] 62S1/2). For efficient detection, a rapid fine-structure mixing (62P3/2 [if & only if] 62P1/2) is required and is provided by the presence of ethane in the cell. The absorption properties of this cell are reported as well as its potential application to a selected analytical problem such as the detection of Raman photons.

Download or read book Laser Diagnostics of Reacting Molecular Plasmas for Plasma Assisted Combustion Applications written by Caroline Winters and published by . This book was released on 2017 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has produced extensive sets of new data on low-temperature plasma-assisted fuel oxidation in hydrogen-oxygen-argon and hydrocarbon-oxygen-argon mixtures. The measurements have been made in two different plasma flow reactors, at an initial temperature of 500 K and pressures ranging from 300 Torr to 700 Torr. In both reactors, the plasma is generated by a high peak voltage, ns pulse discharge, operated at high pulse repetition rates (up to 20 kHz). Metastable Ar atom number density distributions in the discharge afterglow are measured by Tunable Diode Laser Absorption Spectroscopy (TDLAS), and used to characterize plasma uniformity. Temperature in the discharge-excited reacting flow is measured by Rayleigh scattering. Two-photon Absorption Laser Induced Fluorescence (TALIF) is used to measured absolute H and O atom number densities. The results are compared with predictions of a kinetic model analyzing reaction kinetics of excited species and radicals generated by the plasma at low temperatures and high pressures. The modeling predictions show good agreement with the data, with the exception of fuel-limited mixtures, when nearly all fuel available in the mixture of reactants is oxidized in the discharge. Kinetic modeling analysis identified dominant processes of generation and decay of atomic and radical species in the discharge and in the afterglow. At the present low-temperature conditions, the effect of chain branching reactions on plasma-assisted fuel oxidation kinetics is insignificant.

Download or read book Laser Aided Diagnostics of Plasmas and Gases written by K Muraoka and published by CRC Press. This book was released on 2016-04-19 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt: Updated and expanded from the original Japanese edition, Laser-Aided Diagnostics of Gases and Plasmas takes a unique approach in treating laser-aided diagnostics. The book unifies the subject by joining applications instead of describing each application as a totally separate system. In taking this approach, it highlights the relative strengths of

Download or read book Laser Induced Plasmas Optical Diagnostics written by Magesh Thiyagarajan and published by . This book was released on 2011-11 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Diagnostics and Photochemical Processing for Semiconductor Devices written by R. M. Osgood and published by North Holland. This book was released on 1983 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser based Diagnostics for Condensation in Laser ablated Copper Plasmas written by and published by . This book was released on 1991 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: We are investigating the thermodynamic conditions under which condensation occurs in laser-ablated copper plasma plumes. The plasma is created by XeCl excimer laser ablation (308 nm, 350 mJ/pulse) at power densities from 500--1000 MW/cm2. The atomic vapor expands rapidly into backing pressures of helium ranging from 0--50 torr. The backing gas serves to slow the vapor before it rarefies and provides a third body to stabilize collision complexes between vapor atoms to produce small cluster species. The formation of these small clusters is indicative of the onset of condensation, a process which, under the proper conditions, eventually forms macroscopic particulate in the plume. We use laser-induced fluorescence (LIF) to probe both atomic copper and the copper dimer molecule, Cu2. Velocities of atomic Cu have been obtained by a time-of-flight method under varying conditions of backing gas pressure. At low pressure (10 mtorr), the atomic Cu velocity peaks at approximately 2 x 106 cm/s. Excitation scans of the Cu2 A - X (0,0) and (1,1) bands yield both a rotational temperature and a vibrational temperature. Direct laser beam absorption is used to determine the number density of atomic copper. Rayleigh scattering from particulate is easily observable under conditions favorable to particulate production. The Cu2 LIF and Rayleigh-scattered signals disappear instantaneously in the absence of the ablation laser pulse indicating that the particulate is formed during a single laser shot. 10 refs., 9 figs.

Download or read book Laser Diagnostics for Combustion Temperature and Species written by Alan C. Eckbreth and published by CRC Press. This book was released on 2022-01-27 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines the variety of potential laser diagnostic techniques and presents a considerable theoretical foundation elucidating physics relevant to the laser diagnostics. It explains the Raman-based approaches for major species and temperature measurements.

Download or read book Laser Applications in Plasma Physics 1962 1968 written by International Atomic Energy Agency and published by . This book was released on 1969 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optical and X ray Diagnostics of the Formation of Laser Induced Plasmas in Gases and Vacuum written by Dmitri Nikitine and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Diagnostics of Laser Produced Plasmas written by P. W. Chan and published by . This book was released on 1975 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Light scattering and holographic interferometry diagnostics using a ruby laser source have been applied to study a CO2 laser-induced argon breakdown with peak power density estimates at approximately 5 x 10 to the 9th power W per sq cm at subatmospheric pressures. Light scattering results indicate well-defined but asymmetric ion-acoustic peaks. Assuming Maxwellian velocity distributions for the ions and the electrons, the ion temperature is estimated to be 4.3 eV and the electron temperature 43 eV at 200 ns after spark initiation. However, there is indication that the scattered intensity is above thermal so that the Maxwellian velocity assumption may not be valid. The asymmetry of the ion peaks indicates a relative drift of the electrons with respect to the ions. In addition, a Doppler shift of the entire scattered spectrum is also observed. Holographic interferometry provides three-dimensional density profile of the laser peak spark at several gas pressures and different times after spark initiation. The pressure-dependence studies show that high electron densities are produced at high pressures due to larger absorption and smaller plasma dimensions. The temporal dependence indicates that at the peak of the CO2 pulse, the plasma produces a sharp shock front (high density, low temperature) followed by a period of minimum on-axis electron density, resulting from local laser heating of the plasma.

Download or read book Laser Plasma Generation and Diagnostics written by Richard F. Haglund and published by SPIE-International Society for Optical Engineering. This book was released on 2000 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nonlinear Laser Diagnostics for Combustion and Plasma Processes written by and published by . This book was released on 1997 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: Significant milestones for quantitative laser-based diagnostics of reacting flows were reached on two separate tasks: (1) the extension of laser-based diagnostics to shorter vacuum ultraviolet (vuv) wavelengths and (2) the development of amplified spontaneous emission (ASE) diagnostics for light atoms. For the first task, phase-matching was applied to produce significant increases in vuv laser intensities, producing over 5 mu J at Lyman alpha (121.6 nm) in a mixture of krypton and argon. Factors affecting the long-term stability of vuv powers were studied. The diagnostic potential of two-photon excited ASE of atomic hydrogen and oxygen was explored in a variety of low-pressure flames. Direct ASE gain measurements gave oxygen concentrations. A model of the ASE signal was developed, and a new understanding of both ASE and laser-induced fluorescence of two-photon excited atoms emerged from this model.

Download or read book Semiconductor Laser Engineering Reliability and Diagnostics written by Peter W. Epperlein and published by John Wiley & Sons. This book was released on 2013-01-25 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference book provides a fully integrated novel approach to the development of high-power, single-transverse mode, edge-emitting diode lasers by addressing the complementary topics of device engineering, reliability engineering and device diagnostics in the same book, and thus closes the gap in the current book literature. Diode laser fundamentals are discussed, followed by an elaborate discussion of problem-oriented design guidelines and techniques, and by a systematic treatment of the origins of laser degradation and a thorough exploration of the engineering means to enhance the optical strength of the laser. Stability criteria of critical laser characteristics and key laser robustness factors are discussed along with clear design considerations in the context of reliability engineering approaches and models, and typical programs for reliability tests and laser product qualifications. Novel, advanced diagnostic methods are reviewed to discuss, for the first time in detail in book literature, performance- and reliability-impacting factors such as temperature, stress and material instabilities. Further key features include: practical design guidelines that consider also reliability related effects, key laser robustness factors, basic laser fabrication and packaging issues; detailed discussion of diagnostic investigations of diode lasers, the fundamentals of the applied approaches and techniques, many of them pioneered by the author to be fit-for-purpose and novel in the application; systematic insight into laser degradation modes such as catastrophic optical damage, and a wide range of technologies to increase the optical strength of diode lasers; coverage of basic concepts and techniques of laser reliability engineering with details on a standard commercial high power laser reliability test program. Semiconductor Laser Engineering, Reliability and Diagnostics reflects the extensive expertise of the author in the diode laser field both as a top scientific researcher as well as a key developer of high-power highly reliable devices. With invaluable practical advice, this new reference book is suited to practising researchers in diode laser technologies, and to postgraduate engineering students.

Download or read book Laser Processing and Diagnostics written by Dieter Bäuerle and published by Springer. This book was released on 1984 with total page 582 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Development of Diode Laser Infrared Absorption Spectroscopy as a Plasma Diagnostic written by Robert Leslie McClain and published by . This book was released on 1991 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Diagnostics of RF Hydrogen Plasma Reactors written by Bryan L. Preppernau and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two photon laser induced fluorescence (TALIF) has been developed as a convenient and reliable diagnostic of H atoms in plasma processing environments. It has high spatial and temporal resolution, good sensitivity, and the capability of absolute concentration measurements. Detailed diagnostics have been carried out in plasma reactors with and without semiconducting wafers. These measurements have led to a model that incorporates H atom production, diffusion, and surface recombination. This model has accurately predicted both the spatial and temporal behavior of the H-atom concentration in a plasma processing environment.

Download or read book Development of Laser plasma Diagnostics Using Ultrafast Atomic scale Dynamics 96 ERD 046 Final Report written by and published by . This book was released on 1997 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultrashort laser pulse systems allow examination of intense, ultrafast laser-plasma interactions. More specifically, intense laser irradiation can induce short xuv/x-ray bursts from the surface of condensed phase targets. Ultrafast xuv/x-ray detection is needed to understand laser-plasma interactions in this dynamic regime. Support of the Stockpile Stewardship and Management Program requires this critical understanding. Our effort here has been to extend understanding of atomic-scale dynamics in such environments with the goal of developing next generation ultrafast xuv/x-ray diagnostics where the sensors will be the atoms and ions themselves and the time resolution will approach that of the induced atomic transitions ((almost equal to) a few femtoseconds). Pivotal contributions to the rapidly developing field of highly nonperturbative interactions of ultrashort pulse lasers with atoms/ions have been made at this laboratory. In the visible/infrared wavelength regions the temporal and spectral content of ultrashort laser pulses are now reliably monitored within a single pulse using frequency resolved optical gating (FROG) which is based on rapid nonlinear optical processes such as the Kerr effect. New applications of this basic concept are still being developed. Corresponding detection for the xuv/x-ray wavelengths does not exist and is urgently needed in many laboratory programs. The FROG technique cannot be applied in the xuv/x-ray region. Current x-ray streak camera technology is limited to (almost equal to)0.5 picosecond resolution.