Spectroscopic analysis and temporal evolution of laser-induced plasma in different samples

This book examines the theory and applications of laser-induced plasmas. Topics discussed include the application of laser-induced plasma expansion models for thin film deposition; cluster-containing plasma fumes for high-order harmonic generation laser radiation; pulsed laser deposition of nanocrystalline V2O5 thin films; nanosecond and femtosecond laser ablation of TeO2 crystals; resonant harmonic generation of short pulse laser in plasma and the influence of the heterogeneous nature of laser ablation on near-surface plasma formation and propagation.Peer Reviewe

Time-resolved spectroscopic diagnostic of laser-induced plasma on Germanium targets

Time-resolved optical emission measurements have been made in laser-induced plasma plumes following CO2 pulsed-laser (10.591 lm, 64 ns and intensity from 0.27 to 4.9 GW cm#2;2) irradiation of germanium targets. The temporal behavior of Ge atoms and ionized excited species Ge3þ, Ge2þ, and Geþ is reported. The results show a faster decay of the continuum emission and Ge3þ, Ge2þ ionic species than in the case of Geþ and neutral Ge atoms. The velocity distributions for Ge3þ, Ge2þ, Geþ, and Ge species are obtained from time-of-flight measurements. Electron density in the laser-induced plasma was estimated from the analysis of spectral data at various times from the CO2 laser pulse incidence. From the intensity decay with the delay time for Geþ, Ge2þ, and Ge3þ, we estimated the three-body electron-ion recombination rate constants for these species. VC 2011We gratefully acknowledge the support received in part by the DGICYT (Spain) Projects: MEC: CTQ2008-05393/ BQU and MEC: CTQ2010-15680/BQU for this research.Peer Reviewe

Spectroscopic analysis of chemical species in carbon plasmas induced by high-power IR CO2 laser

This book describes certain fundamentals of laser-induced breakdown spectroscopy (LIBS) and the experimental results obtained from ultraviolet-visible-near infrared (UV-Vis-NIR) spectra induced by laser ablation of a graphite target. The characteristics of the spectral emission intensities from the different species have been investigated as functions of the ambient pressure, laser irradiance, delay time and distance from the target. Excitation, vibrational and rotational temperatures, as well as ionization degree and electron number density for some species were estimated. Time-gated spectroscopic studies have allowed estimation of time-of-flight (TOF) and propagation velocities for various emission speciesPeer Reviewe

Time-resolved optical emission spectroscopy study of laser-ablation of Germanium targets

XXII Reunión Nacional de Espectroscopía. VI Congreso Ibérico de Espectroscopía, Porto, 8th to 10th September 2010Peer Reviewe

Time-resolved spectroscopic diagnostic of the CO2 plasma induced by a high-power CO2 pulsed laser

Laser-induced breakdown spectroscopy of CO2 plasma, initially at room temperature and pressures ranging from 6.4 to 101 kPa was investigated using a transverse excitation atmospheric CO2 pulsed laser (λ = 10.532 μm, a full width at half maximum of 64 ns, and an intensity from 1.2 to 5.6 GW cm-2). The strong emission of the CO2 plasma shows excited neutral O and C atoms and ionized O+ and C+ species. The medium-weak emission is due to electronic relaxation of excited species C2+, O2+, N+, N, H and molecular band systems of C2(E1Σg +-A 1Πu; e3Πg-a 3Πu; d3Πg-a 3Πu), CN(B2Σ+-X 2Σ+; A2Π- X2Σ+), O2(b1Σ g +-X3Σg -), O 2 +(A2Πu-X2Π g), N2(C3Πu-B3Π g) and N2 +(B2Σ u +-X2Σg +). The characteristics of the spectral emission intensities from different species have been investigated as a function of the laser irradiance and CO2 pressure. Optical breakdown threshold intensities and plasma temperatures were obtained. The evolution of the luminous plasma was examined by time-resolved optical emission spectroscopy. The velocity distributions for different species were obtained from time-of-flight (TOF) measurements. Electron density in the laser-induced plasma was estimated from the Stark broadening method. The temporal evolution of the intensities in the TOF profiles for O+, O2+, C, C+ and C2+ species has been used for the estimation of the corresponding three-body electron-ion recombination rate constants. © 2011 Elsevier B.V. All rights reserved.We gratefully acknowledge the support received in part by the DGICYT (Spain) Projects: MEC: CTQ2008-05393/BQU and MEC: CTQ2010-15680/BQU for this research.Peer Reviewe

Time-resolved optical emission spectroscopic measurements of He plasma induced by a high-power CO2 pulsed laser

Laser-induced breakdown spectroscopy of helium plasma, initially at room temperature and pressures ranging from 12 to 101 kPa was investigated using a transverse excitation atmospheric CO2 pulsed laser (λ = 9.621 and 10.591 μm, a full width at half maximum of 64 ns, and an intensity from 1.5 to 5.36 GW cm-2). The helium breakdown spectrum is mainly due to electronic relaxation of excited He, He+ and H. Plasma characteristics were examined in detail on the emission lines of He and He + by the time-integrated and time-resolved optical emission spectroscopy technique. Optical breakdown threshold intensities, ionization degree and plasma temperatures were obtained. An auxiliary metal mesh target was used to analyze the temporal evolution of the species in the plasma. The results show a faster decay of the continuum emission and He+ species than in the case of neutral He atoms. The velocity and kinetic energy distributions for He and He+ species were obtained from time-of-flight measurements. Electron density in the laser-induced plasma was estimated from the analysis of spectral data at various times from the laser pulse incidence. Temporal evolution of electron density has been used for the estimation of the three-body electron-ion recombination rate constant. © 2010 Elsevier B.V.We gratefully acknowledge the support received in part by the DGICYT (Spain) Projects: MEC: CTQ2007-60177/BQU and MEC: CTQ2008-05393/BQU for this research.Peer Reviewe

Spectroscopic study of plasma plumes generated by IR CO2 pulsed laser on carbon targets

XXI Reunión Nacional de Espectroscopia. V Congreso Ibérico de Espectroscopia, Murcia, 9-11 de Septiembre de 2008Peer Reviewe

Optical emission studies of nitrogen plasma generated by IR IR CO2 laser pulses

XXI Reunión Nacional de Espectroscopia. V Congreso Ibérico de Espectroscopia, Murcia, 9-11 de Septiembre de 2008Peer Reviewe

Spatial characterization of the laser-induced plasma plumes generated by IR CO2 pulsed laser on carbon targets

Spatially resolved optical emission analysis was carried out for the plasma plume, produced by high-power tunable IR CO2 pulsed laser ablation of graphite, at λ=9.621 μm and with laser fluence of 342 J∈cm-2. Wavelength-dispersed spectra of the plume, at medium vacuum conditions (P air=4 Pa) and concentrated close to the target, reveal C, C+, C2+, C3+, C4+, N, H, O, and molecular emissions between different electronic states of C2, CN, OH, CH, and NH. The characteristics of the spectral emission intensities from different species have been investigated as functions of the distance (up to 20 cm) from the sample surface. Vibrational temperatures in the laser-induced plasma have been estimated at various distances from the target surface. © 2008 Springer-Verlag.This work was partially supported by the Spanish MEC Project CTQ2007-60177/BQU.Peer Reviewe

Time characterization of the laser ablation plasma plume of CaO produced by a pulsed infrared TEA-CO2 laser

XXIV Reunión Nacional de Espectroscopia-VIII Congreso Ibérico de Espectroscopia; organizan Sociedad de Espectroscopia Aplicada (SEA) y Universidad de La Rioja. P094Time characterization of the laser ablation plasma plume of CaO produced by a pulsed infrared TEA-CO2 laser J.P. Cid1,2, J.J. Camacho1, L. Diaz3, V.Oliver1, J.M.L. Poyato1. (1) Departamento de Química-Física Aplicada, Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain, [email protected]. (2) Servicio de Conservación, Restauración y Estudios Científicos del Patrimonio Arqueológico, Universidad Autónoma de Madrid, Cantoblanco 28049, Madrid, Spain. (3) Instituto de Estructura de la Materia, CFMAC, CSIC, Serrano 121, 28006 Madrid, Spain. The underlying physics of laser ablation remains incompletely understood due to complex laser-target and laser-plasma interactions, plasma expansion and confinement, plasma condensation interaction processes. The experimental setup and equipment used has been described elsewhere [1]. The laser beam form a transversely excited atmospheric (TEA) CO2 pulsed-laser was focused onto a CaO target. The laser induced plasma was imaged 1:1 onto the entrance slit of different spectrometers. For time-resolved measurements, the detectors are synchronized with the trigger of the laser pulse. A Dove prism was inserted between to lenses into the observation optical path for rotating ¿/2 rad the plasma image for recording 2D spectral images. The spatio-temporal evolution of the calcium oxide plasma produced by a high-power pulsed TEA-CO2 laser has been investigated using optical emission spectroscopy (OES) and imaging methods. The emission observed in the plasma region is mainly due to electronic relaxation of excited Ca, Ca+, Ca2+, O, O+ and CaOH fragments. Time-integrated and time-resolved two-dimensional OES plasma profiles were recorded as function of emitted wavelength and distance from the target. The temperature measurements have been performed by Boltzmann diagram method. The temporal behaviour of specific emission lines of the species was characterized. The results show faster decays for continuum and Ca2+ species than for Ca+ and Ca. The Stark broadening of isolated calcium emission lines was employed for deducting the electron densities.Universidad Autónoma de Madrid (Spain) Project: CEMU-2012-003.Peer Reviewe