This thesis discusses the following on resonant holographic measurements of laser ablation plume expansion: Introduction to laser ablation; applications of laser ablation; The study of plume expansion; holographic interferometry; resonant holographic ...

In femtosecond laser ablation the plume has two components: a faster-moving plasma part and a slower nanoparticle plume which contains most of the ablated material. This paper describes the results of experiments to comprehensively characterize the plume in laser ablation ...

In femtosecond laser ablation the plume has two components: a faster-moving plasma part and a slower nanoparticle plume which contains most of the ablated material. This paper describes the results of experiments to comprehensively characterize the plume in laser ablation ...

This thesis discusses the following on resonant holographic measurements of laser ablation plume expansion: Introduction to laser ablation; applications of laser ablation; The study of plume expansion; holographic interferometry; resonant holographic ...

An annealing model is extended to treat the vaporization process, and a hydrodynamic model describes the ablated material. We find that dynamic source and ionization effects accelerate the expansion front of the ablated plume with thermal vaporization tem...

The (0,0) Swan band of the C{sub 2} molecules in a laser ablation plume produced on the surface of graphite target submerged in water was used as a probe to estimate the density of C{sub 2} molecules in the plume. Observed emission spectra were reproduced excellently by introducing a self-absorption parameter to the theoretical ...

Multiscale computational approach that combines different methods to study laser ablation phenomenon is presented. The methods include the molecular dynamics (MD) breathing sphere model for simulation of the initial stage of laser ablation, a combined MD - finite element method (FEM) approach for simulation of propagation of the laser-induced pressure ...

... Themicro-laser plasma thruster (uLPT) discussed here ... by focusing the laser through a ... ION DENSITY, *DIODE LASERS, VELOCITY, ABLATION ...

We report time-resolved imaging of a laser-ablated carbon plasma plume to investigate the expansion dynamics of C2 and CN in an ambient atmosphere of nitrogen gas at various pressures. An attempt is made to locate C2 and CN species in the carbon plasma plume and correlate them with the results of spectroscopic ...

Pulsed laser ablation is a process in which an intense laser pulse interacts with the matter producing plasma. The present work describes the theoretical work being conducted in the past for the pulsed laser ablation phenomenon. It incorporates the theoretical models being proposed by various researchers around the globe for pulsed laser ...

The dynamic behaviors and optical properties of a ZnO plasma plume produced by pulsed laser ablation using a Nd:YAG laser (wavelength: 532 nm, pulse width: 3 ns) were studied by fast photography using a commercial gated charge coupled device (CCD) camera linked with a delay circuit and by optical emission spectroscopy at various ambient oxygen pressures. ...

An annealing model is extended to treat the vaporization process, and a hydrodynamic model describes the ablated material. We find that dynamic source and ionization effects accelerate the expansion front of the ablated plume with thermal vaporization temperature. The vaporization process and ...

We consider the applicability of the isentropic, adiabatic gas dynamical model of plume expansion for laser ablation in vacuum. We show that the model can be applied to ionized plumes and estimate the upper electron temperature limit on the applicability of the isentropic approximation. The model predictions are ...

Thin films of La0.6Ca0.4CoO3 were grown by pulsed laser ablation with nanosecond and femtosecond pulses. The films deposited with femtosecond pulses (248 nm, 500 fs pulse duration) exhibit a higher surface roughness and deficiency in the cobalt content compared to the films deposited with nanosecond pulses (248 nm, 20 ns pulse duration). The origin of these pronounced ...

The expansion in vacuum of the plume generated by the UV ablation of a LiYF4 crystal was analysed as a function of several parameters: distance from the target along the plume axis, laser fluency and angular dislocation with respect to the plume axis. The study was carried out by the optical ...

We study the temperature evolution of aluminum nanoparticles generated by femtosecond laser ablation with spatiotemporally resolved x-ray-absorption fine-structure spectroscopy. We successfully identify the nanoparticles based on the L-edge absorption fine structure of the ablation plume in combination with the dependence of the edge ...

Ablation of molecular solids with pulsed ultraviolet lasers at atmospheric pressure is an important process in (bio-)organic mass spectrometry. Of practical importance for analytical sampling and analysis are the plume formation and expansion. Plumes formed by atmospheric-pressure laser ...

Femtosecond laser ablation of Ti, Zr, and Hf has been investigated by means of in situ plasma diagnostics. Fast imaging was used to characterize the plasma plume expansion on a nanosecond time scale. In addition, time- and space-resolved optical emission spectroscopy was employed to determine the plume composition ...

Generation and expansion dynamics of aluminum laser plasma plumes generated between parallel plates of varying separation (?Z = 2.0, 3.2, 4.0, and 5.6 mm), which confined plume expansion normal to the ablation surface, were diagnosed. Space and time resolved visible emission spectroscopy in the ...

Laser ablation plasma plume expanding into the ambient atmosphere may be an efficient way to produce nanoparticles. From that reason it would be interesting to study the properties of these laser induced plasmas formed under conditions that are known to be favorable for nanoparticles production. In general, plume behavior can be ...

The behavior of ablated plumes produced by nanosecond scale multiple laser pulses typical for carbon ablation is studied in order to understand the plume expansion dynamics and shielding effect of plume with special interest to ionization of plumes. The ...

The influence of pulsed laser ablation of an aluminum target on the nitrogen plasma produced by electron cyclotron resonance (ECR) microwave discharge has been studied by optical emission spectroscopy (OES) with time and space resolution. The continuous wave (CW) feature of the optical emissions from the ECR nitrogen plasma turns to vary with time and space due to pulsed laser ...

Resonant holographic interferometry (RHI) and dye-laser resonance absorption photography (DLRAP) have been utilized to investigate the expansion of the laser ablation plumes produced by a KrF excimer laser beam (248 nm) focused onto an aluminum target (approximately equals 0.1 cm(exp 2), 2-6 J/cm(exp 2)). Plume ...

The gas dynamics and atomic kinetics of a laser ablation plume of lithium, expanding adiabatically in vacuum, are included in a numerical model, using isothermal and isentropic self-similar analytical solutions and steady-state collisional radiative equations, respectively. Measurements of plume expansion dynamics ...

The effect of ambient gas on the expansion dynamics of the plasma plume generated by excimer laser ablation of a LaMnO{sub 3} target is investigated by using fast photography. The plume propagation in an oxygen environment is examined with pressure ranging from vacuum to a few millibars. Imaging analysis performed ...

The effect of ambient gas on the expansion dynamics of the plasma plume generated by excimer laser ablation of a LaMnO3 target is investigated by using fast photography. The plume propagation in an oxygen environment is examined with pressure ranging from vacuum to a few millibars. Imaging analysis performed over a ...

Determination of the rates of laser ablation (etching) of various materials by powerful (up to 1014 W cm-2) pulsed radiation revealed a considerable reduction in the etching efficiency during shaping of deep ablation channels. The optical characteristics of the resultant plasma � vapour plume were measured. These measurements and ...

Expansion of ablation plumes created by intense ultrashort lasers is determined by various complicated physical processes which have very different spatial and time scales. Since complete simulation by one model is practically impossible, the authors suggest using two models describing initial and final stages that can be matched at an ...

Time development of Sm+ and Sm ablation plume produced by the femtosecond laser irradiation has been investigated. The two-dimensional spatial profiles of Sm and Sm+ emitted from oxidized and non-oxidized Sm surface were visualized using a planar laser-induced fluorescence method. It was observed that the flow velocity of Sm+ is much faster than that of Sm ...

A fluid dynamics model was developed for the ablation of water-rich targets by infrared laser pulses at atmospheric pressure. It incorporates the nonlinear absorption of water and the phase explosion due to superheating. The simulation results show that due to two different phase transition mechanisms, the first, slower plume expansion ...

The ablation by ultrashort laser pulses at relatively low fluences (i.e., in the thermal regime) of solids wetted by a thin liquid film is studied using a generic numerical model. In comparison with dry targets, the liquid is found to significantly affect ablation by confining the solid and slowing down the expansion of the ...

The Simons model is a simple model for calculating the expansion plumes of rockets and thrusters and

Resonant holographic interferometry and dye-laser-resonance-absorption photography have been utilized to investigate the expansion of the laser ablation plumes produced by a KrF excimer laser beam (248 nm) focused onto an aluminum target (about = 0.1 sq cm, 2 - 6 J/sq cm). Plume expansion was ...

The expansion of plasma created by laser ablation is investigated using the fluid model. At the first stage of the expansion, electrons are considered in thermal equilibrium. The presence of highly charged impurities is considered through Poisson's equation. The set of nonlinear differential equations is solved using a moving ...

The formation, composition and propagation of pulsed laser produced plasma plumes from an AlN target have been studied in real time by spatially and temporally resolved optical spectroscopy. The mean front velocity has been measured and appears to be slightly slower in the presence of added gas than in vacuum. In the initial stage of expansion, this ...

The expansion dynamics of Sm{sub 1-x}Nd{sub x}NiO{sub 3} excimer laser ablation plume in background oxygen atmosphere has been investigated using a fast ICCD imaging. The laser fluence was fixed at 2 J{center_dot}cm{sup -2} and the surrounding ambient gas pressure was varied from vacuum to 50 mbars. The imaging data is used to create ...

The expansion of plasma plume produced by a laser ablation is investigated using the self-similar approach. Based on the fluid model and the quasi-neutral assumption, the one dimensional expansion of an either vapor or partially ionized gas is studied for a collisionless plasma in the presence of electrons in ...

Spectroscopic analysis of the emission plumes of graphite, polyimide, polyethylene terepthalate, and polymethylmethacrylate that have been ablated by using a pulsed CO2 laser operating at 10.6 ?m shows the presence of CN and C2, species not previously reported for CO2 laser ablation. The gross dynamics of the luminous ...

parameters of nanosecond laser produced ablation plumes from metal targets.4-6 More recently they have also. The laser spot on the target had an area 2*10-5 cm2 and was slightly elliptical (b/a = 1.4) with the minor. The contaminant peak is prominent for the 1st laser shot on an untreated area of the target surface. It is less

Optical/electrical characterization of transient plasmas generated by high-fluence (up to 1 kJ/cm{sup 2}) laser ablation of various targets revealed as a general feature the splitting of the plume in two structures. In order to account for this behavior, a new fractal hydrodynamic model has been developed in a non-differentiable space-time. The model ...

A self-similar theory and numerical hydrodynamic modeling is developed to investigate the effects of dynamic source and partial ionization on the acceleration of the unsteady expansion of laser-ablated material near a solid target surface. The dynamic source effect accelerates the expansion in the direction perpendicular to the target ...

A self-similar theory and numerical hydrodynamic modeling is developed to investigate the effects of dynamic source and partial ionization on the acceleration of the unsteady expansion of laser-ablated material near a solid target surface. The dynamic source effect accelerates the expansion in the direction perpendicular to the target ...

The expansion of a plasma plume in a background gas is a key problem for film deposition and laser ablation studies. Combined diagnostic measurements of deposition rates and ion time-of-flight (TOF) signals have been used to study the dynamics of a laser ablation plume in an oxygen gas. This ...

Laser materials processing techniques are expected to have a dramatic impact on materials science and engineering in the near future and beyond. One of the main laser materials processing techniques is Pulsed Laser Deposition (PLD) for thin film growth. While experimentalists search for optimal approaches for thin film growth with pulsed laser deposition (PLD), a systematic effort in theory and ...

Silver and gold thin films were deposited by pulsed laser ablation in a controlled Ar atmosphere at pressures between 10 and 100 Pa. Different morphologies, ranging from isolated nanoparticle arrays up to nanostructured thin films were observed. Fast imaging of the plasma allowed deducing the expansion dynamics of the ablated ...

Silver and gold thin films were deposited by pulsed laser ablation in a controlled Ar atmosphere at pressures between 10 and 100 Pa. Different morphologies, ranging from isolated nanoparticle arrays up to nanostructured thin films were observed. Fast imaging of the plasma allowed deducing the expansion dynamics of the ablated ...

A study of the gas dynamics of the vapor plume generated during laser ablation was conducted including a counterpropagating internal shock wave. The density, pressure, and temperature distributions between the external shock wave front and the sample surface were determined by solving the integrated conservation equations of mass, momentum, and energy. The ...

A comparative experimental study of pulsed laser ablation in vacuum of two binary semiconductors, zinc oxide and indium phosphide, has been performed using IR- and visible laser pulses with particular attention to cluster generation. Neutral and cationic Zn{sub n}O{sub m} and In{sub n}P{sub m} particles of various stoichiometry have been produced and investigated by ...

Optical emission of plasma is used to investigate the characteristics of dynamics distribution in the plume generated by ablation of a SiC sample using Nd:YAG laser. The plume expansion dynamics is characterized by time-of-flight measurement. We find that the profiles of Si(I) (390.55 nm) split into two components ...

The dynamics of a laser ablation plume during the first stage of its expansion, just after the termination of the laser pulse is modeled. First, we suppose the laser fluence range low enough to consider a neutral vapor. The expansion of the evaporated material is described by one-component fluid and one-dimensional ...

The dynamics of a laser ablation plume during the first stage of its expansion, just after the termination of the laser pulse is modeled. First, we suppose the laser fluence range low enough to consider a neutral vapor. The expansion of the evaporated material is described by one-component fluid and one-dimensional ...

The expansion of a plume in a background gas of pressure comparable to that used in pulsed laser deposition (PLD) has been analyzed in terms of the model of Predtechensky and Mayorov (PM). This approach gives a relatively clear and simple description of the essential hydrodynamics during the expansion. The model also leads to an ...

To study the expansion and cooling process of the laser induced plasma generated by nanosecond pulsed laser ablation, experiments have been conducted which measure the position of the external shockwaves and the temperature of the vapor plumes. The positions of external shockwaves were determined by a femtosecond laser time-resolved ...

A study of the gas dynamics of the vapor plume generatedduring laser ablation was conducted including a counterpropagatinginternal shock wave. The density, pressure, and temperature distributionsbetween the external shock wave front and the sample surface weredetermined by solving the integrated conservation equations of mass,momentum, and energy. The ...

Pulsed laser generated Fe plasma plumes have been studied near the target surface using time-resolved imaging. A fast gated intensified CCD camera is used to capture the images with a gate width of 2 ns. The plasma plumes were generated using a Q-switched Nd-YAG laser at 1064 nm with a fluence of �2 kJ/cm2. The expansion studies were ...

Pulsed laser ablation of molecular solids is important for identification and quantification in (bio-)organic mass spectrometry, for example using matrix-assisted laser desorption/ionization (MALDI). Recently, there has been a major shift to using MALDI and related laser ablation/post-ionization methods at atmospheric pressure. However, the underlying ...

In this work we report on the properties of the ablation plume and the characteristics of the films produced by ultra-fast pulsed laser deposition (PLD) of TiO2 in vacuum. Ablation was induced by using pulses with a duration of ?300 fs at 527 nm. We discuss both the composition and the expansion dynamics of the ...

Barium and barium oxide targets were irradiated at 248 nm with fluences ranging from 300 - 600 mJ/cm^2 in vacuum and 25 mTorr atmospheres of O_2, N_2, microwave discharged O_2. Time-integrated optical emission from the resulting plume was examined and compared to determine the fate of the Ba^+ ions produced as a result of the ablation process and/or ...

We studied the dynamics of the femtosecond laser ablation of aluminum in an energy range well above the ablation threshold with the ultrafast time-resolved x-ray-absorption fine structure imaging technique. Analyzing the spectral structures near the L absorption edge that appeared in one-dimensional images of soft-x-ray absorbance, we successfully ...

... Characterization of vapour plume species and deposition residues resulting from pulsed laser ablation of a ... ablation of a graphite/epoxy composite ...

... Pyrolysis gas pressure inside the TPS of Formfted: Endnote Reference Pioneer ... ablation. eleted:__ J_Formatted: Endnote Reference ...

Lasers represent an efficient and versatile tool to produce and to arrange in organized dispositions nanometer-sized particles, obtaining extended nanostructures with increasing degrees of complexity. In the first part of the chapter, the basic mechanisms of nanoparticle formation for nanosecond laser ablation in an ambient gas atmosphere and femtosecond ...

We used time-gated optical emission spectroscopy to investigate the characteristics of aluminum plumes and their vacuum expansion after femtosecond laser ablation at different fluences. The prominent feature is the presence of two main classes of species in the plume: very fast Al atoms and ions preceding the ...

A theoretical study of cluster formation in the plume produced by nanosecond laser pulses of moderate intensity in vacuum is undertaken on the basis of the Smoluchowski rate equations. Dynamics of the laser-induced plume expansion is described in a spherical approximation, taking into account ionization/recombination kinetics, the heat ...

The fundamental physical processes that follow ultraviolet laser ablation of polycarbonate and borosilicate glass in air have been investigated using photodeflection as a function of the distance from the surface to probe laser. Four features were observed in the data sets for each material. Two of these features correlate well with gas dynamical predictions for the ...

We have used time and space-resolved optical emission spectroscopy to study the expansion dynamics of the plasma generated by pulsed laser ablation of solid targets of the recently discovered superconducting MgB2 into a background Ar gas at different pressures. Our analysis clearly indicates that, above a fixed pressure, plasma propagation into Ar leads to ...

The structure and expansion characteristics of the plasma plume produced by laser ablation of a bulk tin target in vacuum have been investigated. A Q-switched Nd: YAG laser with 1064 nm wavelength, 5 ns pulse width, and the order of 10^11 W/cm^2 power density was employed to create ablation plasma. Time-of-flight ...

Combined laser ablation and pulse modulated radio-frequency (RF) discharge for deposition of CNalpha films was studied by the use of optical emission spectroscopy. Chemically active nitrogen was produced by RF discharge, concentrated between two small electrodes. Influence of RF power, nitrogen pressure, modulation frequency and pulse rate on nitrogen species production was ...

We demonstrate that the average size and the size distribution of nanoparticles produced by ultrashort laser ablation in vacuum can be modified by irradiation of the nanoparticles' plume during its vacuum expansion with a nanosecond, UV laser pulse. The experimental results are interpreted by means of a simple analytical model of the ...

The interaction of a laser-generated ablation plume with a background gas is of current interest for several materials-fabrication applications. During pulsed laser deposition (PLD) of thin films by laser ablation, for example, an ambient back ground gas (pressure usually {<=} 300 mTorr) is often employed. The dynamics of the ...

12 A 2D gas-dynamic model of laser ablation an ambient gas atmosphere is proposed. To obtain the boundary conditions at the evaporated target surface, a nonlinear heat transfer problem in the target including the dynamics of the melt and evaporation fronts is considered. Back condensation of the vapor at the target is taken into account. At later stages, compete absorption of ...

The evolution features of lithium ions and neutrals generated by two different schemes viz. the laser-blow-off (LBO) of multicomponent LiF-C thin film and conventional laser ablation (referred here as LPP) from solid lithium have been studied using optical emission spectroscopic technique. The optical signal emitted by Li I (at 670.8 nm) and Li II (548.4 nm) was monitored as a ...

Neutral and cationic Zn n O m clusters of various stoichiometry have been produced by nanosecond laser ablation of ZnO in vacuum and investigated by time-of-flight mass spectrometry. Particular attention was paid to the effect of laser wavelength (in the range from near-IR to UV) on cluster composition. Under 193-nm laser ablation, the charged clusters ...

A two-stage two-dimensional (2D) gas-dynamic model of laser ablation in an ambient gas atmosphere is proposed. The initial one-dimensional stage of the process is related to the ablation plume formation under the action of a laser pulse (duration of the order of 10 ns; fluence about several J/cm2; laser spot diameter about 1 mm) and ...

The effect of laser wavelength on heating of the ablated carbon plume is studied. The plasma absorption coefficients are calculated in order to analyze the results and an experiment is conducted using the first, second, and third harmonic of a Nd:YAG laser. Plasma temperature and electron density in the early phase of expansion in ...

The effect of laser wavelength on heating of the ablated carbon plume is studied. The plasma absorption coefficients are calculated in order to analyze the results and an experiment is conducted using the first, second, and third harmonic of a Nd:YAG laser. Plasma temperature and electron density in the early phase of expansion in ...

This work focuses on the study of the plumes obtained in the double pulse orthogonal Laser Induced Breakdown Spectroscopy (LIBS) in the pre-ablation configuration using both spectroscopic and shadowgraphic approaches. Single and double pulse LIBS experiments were carried out on a brass sample in air. Both the distance of the air plasma from the target ...

The formation of nanoparticles in a plasma produced by the interaction of ultrashort laser pulses with gold has been investigated. Three different experimental techniques were employed. (i) The plume expansion was characterized using fast imaging with the aid of an intensified charge-coupled device. (ii) The plasma composition was analyzed using time- and ...

The formation of nanoparticles in a plasma produced by the interaction of ultrashort laser pulses with gold has been investigated. Three different experimental techniques were employed. (i) The plume expansion was characterized using fast imaging with the aid of an intensified charge-coupled device. (ii) The plasma composition was analyzed using time- and ...

The irradiation of a steel surface in atmospheric pressure ambient was performed to study the surface nanostructuring resulting from the formation of a backward-deposited layer. The dynamics of the plume expansion and of the nanoparticle deposition process were investigated by in situ time-resolved optical analysis. Scanning electron microscopy and atomic ...

An experimental study on the pulsed laser ablation of copper by using Nd-YAG laser radiation of 1064 nm wavelength at a fluence of 13 J/cm2 is reported. A time-resolving plane Langmuir probe, placed at various angles with respect to the target surface normal, is used to record temporal variation of ion currents during the plasma expansion in vacuum. The ...

Time-of-flight (TOF) mass spectra for a peptide (Y(6)) were obtained by utilizing matrix-assisted infrared laser desorption ionization (IR-MALDI) with glycerol as the matrix and by ultraviolet MALDI with ?-cyano-4-hydroxycinnamic acid (CHCA), sinapinic acid (SA), and 2,5-dihydroxybenzoic acid (DHB). Collisional activation during ion extraction and exothermicity in the gas-phase proton transfer ...

Time-of-flight (TOF) mass spectra for a peptide (Y6) were obtained by utilizing matrix-assisted infrared laser desorption ionization (IR-MALDI) with glycerol as the matrix and by ultraviolet MALDI with ?-cyano-4-hydroxycinnamic acid (CHCA), sinapinic acid (SA), and 2,5-dihydroxybenzoic acid (DHB). Collisional activation during ion extraction and exothermicity in the gas-phase proton transfer were ...

The aim of this study is to find thermal conditions for the formation of carbon annotates in a laser furnace. The proposed model includes a multi-species formulation for concentration of chemical components combined with the compressible Euler equations. An axisymmetric unsteady computational gas dynamic model of plume expansion into ambiance has been ...

In this paper, the plume expansion dynamics of an ablated Sm2O3, Nd2O3 and NiO mixture oxides target by KrF laser into background oxygen atmosphere has been investigated using a fast ICCD imaging. The laser fluence was fixed at 2 J cm?2 and the surrounding ambient gas pressure was varied from vacuum to 50 mbar. Some effects as double ...

Laser ablation of bulk High Temperature Superconductor (HTS) material promises to provide a useful means of producing high quality HTS thin films. Mass spectrometric probes of the ablation plume provide a microscopic understanding of the ablation event an...

Using picosecond time-resolved shadowgrams and interferograms, we measured the lateral expansion of an early stage ablation plasma induced by a 1064 nm, 35 ps laser pulse on a copper target. The plasma was found to have an electron density on the order of 10{sup 20} cm{sup -3} near the target surface. Prior to the expanding material vapor ...

... 4. TITLE AND SUBTITLE Plume Expansion and Ionization in a Micro Laser Plasma Thruster (Paper) 5a. CONTRACT NUMBER 5b. ...

... The micro-laser plasma thruster (micro ... EXPANSION, *IONIZATION, *LASER APPLICATIONS, *PLUMES ... PLASTICS, DIODE LASERS, CELLULOSE ...

The 355 nm laser pulse from THG (Third Harmonic Generation) of a Qswitched Nd3+ : YAG laser was used to ablate silicon mounted in air. The time-and space-resolved optical emission spectra were measured for different pulse energy in the wavelength range of 380-420 nm, the emission spectra of N+ was found for impact ionization of air near target surface on the early stage of ...

... Accession Number : ADD411034. Title : Heat transfer and ablation rate measurement in saturn s-11 ullage motor exhaust plume. ...

... PULSED LASER ABLATION OF A GRAPHITE/ EPOXY COMPOSITE ... Graphite/Epoxy Composite, Laser Ablation, Laser Shock, Time-of-Flight 30 ...

The KrF-laser ablation of graphite into 300 Torr of He, Ne, Ar, and Xe has been studied by fast imaging of the plasma emission and post-deposition analyses of collected film deposits. In each case, the soot which was redeposited on the irradiated rod following ablation was highly fullerene-deficient compared to the material collected on the sample disk 1.5 ...

Experimental evidence of the appearance of a proper periodic dynamics in a plasma plume created by pulsed laser ablation is considered as a hint for the presence of a self-organization scenario that explains similar phenomena observed in plasma diodes.

The transport dynamics of laser-ablated neutral/plasma plumes are of significant interest for film growth by pulsed-laser deposition of materials since the magnitude and kinetic energy of the species arriving at the deposition substrate are key processing...

A numerical modelling describing a pulsed nanosecond laser interaction with a titanium target is presented, resulting in the study of the plume expansion in vacuum or in background gas, using the species transport model available in Fluent computational fluid dynamics code. The heat transfers in the solid target and the molten material are modeled using an ...

A numerical modelling describing a pulsed nanosecond laser interaction with a titanium target is presented, resulting in the study of the plume expansion in vacuum or in background gas, using the species transport model available in Fluent computational fluid dynamics code. The heat transfers in the solid target and the molten material are modeled using an ...

Tin doped indium oxide (ITO) is a n-type highly degenerate, wide band-gap semiconductor that is extensively used for many engineering applications. Pulsed laser ablation of indium tin oxide in the nano and femtosecond regime has been performed in our laboratory. Plume diagnostics has been carried out by means of a fast Intensified Coupled Charge Device ...

Rapid transformations through the liquid and vapor phases induced by laser-solid interactions are described by the authors` thermal model with the Clausius-Clapeyron equation to determine the vaporization temperature under different surface pressure condition. Hydrodynamic behavior of the vapor during and after ablation is described by gas dynamic equations. These two models ...

Rapid transformations through the liquid and vapor phases induced by laser-solid interactions are described by the authors' thermal model with the Clausius-Clapeyron equation to determine the vaporization temperature under different surface pressure condition. Hydrodynamic behavior of the vapor during and after ablation is described by gas dynamic equations. These two models ...

The physical mechanisms that enable short pulses of high-intensity ultraviolet laser radiation to remove tissue, in a process known as laser ablation, remain obscure. The thermodynamic response of biological tissue to pulsed laser irradiation was investigated by measuring and subsequently analyzing the stress transients generated by pulsed argon fluorine (ArF, lambda = 193 nm) ...

... of Carbon Nanotube Formation in a Laser Produced Plume: An Investigation of the Metal Catalyst by Laser Ablation Atomic Fluorescence Spectroscopy ...

... HEATING, GLASS FIBERS, HIGH ALTITUDE, PLUMES, LAUNCHERS, CONVECTION(HEAT TRANSFER), NUMBERS, ALTITUDE, AREA ...

... of Carbon Nanotube Formation in a Laser Produced Plume: An Investigation of the Metal Catalyst by Laser Ablation Atomic Fluorescence Spectroscopy ...

... Descriptors : *MATHEMATICAL MODELS, SIMULATION, ABLATION, PHYSICAL PROPERTIES, FILMS, PULSED LASERS, DEPOSITION, PLUMES ...

... of Carbon Nanotube Formation in a Laser Produced Plume: An Investigation of the Metal Catalyst by Laser Ablation Atomic Fluorescence Spectroscopy ...

Plasma plume induced by laser ablation of a hydroxyapatite (Ca10(PO4)6(OH)2) target was studied in different ambient conditions. ArF excimer laser operated at the wavelength of 193 nm with the pulse energy of 300 mJ and 20 ns pulse duration. The emission spectra of the plasma plume were registered with the use of a fast gate, lens ...

The first reported planar laser-induced fluorescence (PLIF) images depicting the relative ground-state, neutral density of Si within a pulsed laser ablation (PLA) plume as it expands into vacuum and 10 mTorr Ar are presented. Several images acquired with the laser detuned incrementally must be superimposed to produce images which compensate for Doppler ...

Numerical modeling of the expansion of electric thruster plumes provides direct means for predicting spacecraft surface contamination and erosion due to plume ions. A software package named COLISEUM that is capable of self-consistently modeling plasma pro...

Numerical modeling of the expansion of electric thruster plumes provides direct means for predicting spacecraft surface contamination and erosion due to plume ions. A software package named COLISEUM that is capable of self-consistently modeling plasma pro...

A laser ablation apparatus having a laser source outputting a laser ablation beam includes an ablation chamber having a sidewall, a beam divider for dividing the laser ablation beam into two substantially equal halves, and a pair of mirrors for converging the two halves on a surface of the target from complementary ...

A laser ablation apparatus having a laser source outputting a laser ablation beam includes an ablation chamber having a sidewall, a beam divider for dividing the laser ablation beam into two substantially equal halves, and a pair of mirrors for converging the two halves on a surface of the target from complementary ...

... larger expansion ratios, approx. 8 to 32, for optimum expansion to 1 bar. Expansion of laser-ablated Delrin propellant appears to convert the ...

Formation of carbon nanoclusters in a single-laser-pulse created ablation plume was studied both in vacuum and in a noble gas environment at various pressures. The developed theory provides cluster radius dependence on combination of laser parameters, properties of ablated material, and type and pressure of an ambient gas in agreement ...

The plume dynamics in the presence of an ambient gas is very intriguing physics. The expansion of a laser-produced plasma in the presence of an ambient gas leads to internal plume structures, plume splitting, sharpening, confinement, etc. We investigated propagation dynamics of an expanding tin ...

Laser-induced breakdown spectroscopy (LIBS) has been used to map the distribution of particulate matter inside the plume created by laser ablation of a brass target. The spatial density distribution of the different components of the plume was determined in an attempt to reveal the mechanism of fractionation in the process of the laser ...

We have developed an extreme sensitive trace element detection technique that has been labeled Laser ablation atomic fluorescence (LAAF) spectroscopy, and applied to a nanometer-scale solid surface analysis. The absolute weight of the detection limit of 870 ag (10-18g) and high depth resolution of 3.6 nm had been demonstrated in trace sodium detection of ...

Laser ablation of copper with a 4 ns laser pulse at 1064 nm was studied with a series of synchronized shadowgraph (100 fs laser pulses at 400 nm) and emission images (spectral line at 515 nm). Data were obtained at two laser pulse energies (10 and 30 mJ) and in three background gases (He, Ne, and Ar) at atmospheric pressure. The laser energy conversion ratio and the amount of ...

Copper targets are irradiated in the ablation regime by pairs of equal, time-delayed collinear laser pulses separated on a timescale going from ~2 ps to ~2 ns. The ablation plume is characterized by ion probe diagnostic, fast imaging, and temporally and spatially resolved optical emission spectroscopy. The variation in the ...

The structure and evolution of the laser-induced vapor plume and shockwave were measured from femtosecond time resolved shadowgraph images. By changing the wavelength of the probe beam (400 and 800 nm), differences in the opacity of the vapor plume were measured as a function of delay time from the ablation laser pulse. The evolution ...

We report on investigations of plasmas produced by laser ablation of fresh potatoes using infrared nanosecond laser radiation. A twin laser system consisting of two Nd:YAG oscillators was used to generate single or double pulses of adjustable interpulse delay. The potatoes were irradiated under ambient air with moderate pulse energies of about 10 mJ. The ...

This work concludes our discussion of the image processing technique developed earlier for determination of specific impulse (Isp) for Ablative Laser Propulsion (ALP). The plasma plumes are recorded with a time-resolved intensified charge-coupled device (ICCD) camera. The plasma was formed in vacuum ({approx} 3x10-3 Torr) by focusing output pulses of a ...

Free-running Er:YAG lasers are used for precise tissue ablation in various clinical applications. The ablated material is ejected into the direction perpendicular to the tissue surface. We investigated the influence of shielding by the ablation plume on the energy deposition into an irradiated sample because it ...

... to soot influence on high altitude plume radiance ... expansion; namely, heterogeneous condensation of soot ... plumes at very high altitudes (Apollo 8 ...

... Included is a study that compares results from a hybrid particle-in-cell model (AQUILA) with Monte Carlo collisions to data obtained from the plume ...

... Included is a study that compares results from a hybrid particle-in-cell model (AQUILA) with Monte Carlo collisions to data obtained from the plume ...

Mechanisms of energy transport during ultrashort laser pulses (USLPs) ablation are investigated in this paper. Nonequilibrium electron-transport, material ionization, as well as density change effects, are studied using atomistic models--the molecular dynamics (MD) and Monte Carlo (MC) methods, in addition to the previously studied laser absorption, heat conduction, and stress ...

Mechanisms of energy transport during ultrashort laser pulses (USLPs) ablation are investigated in this paper. Nonequilibrium electron-transport, material ionization, as well as density change effects, are studied using atomistic models�the molecular dynamics (MD) and Monte Carlo (MC) methods, in addition to the previously studied laser absorption, heat conduction, and ...

The time span of plume dynamics in laser ablation of carbon ranges from nanoseconds to milliseconds. Multi-time step approach is developed to study the plume dynamics over this entire range with minimum requirements of numerical computational resources. This approach is applied to study one of the important aspects of nanosecond-scale ...

Laser ablation of bulk High Temperature Superconductor (HTS) material promises to provide a useful means of producing high quality HTS thin films. Mass spectrometric probes of the ablation plume provide a microscopic understanding of the ablation event and plume development as well as providing ...

Gated photon counting spectroscopy and species-resolved ICCD photography were used to study the weak plasma luminescence following the propagation of the initial ablation plume in vacuum and during the rebound of the plume with a substrate during pulsed l...

Emission from YBCO laser-ablated plumes was studied to characterize the PLD process. A KrF laser was used to ablate a bulk YBCO target at oxygen pressures ranging from 50-400 mTorr. Spectra were collected for the 500-860 nm bandpass at target distances ra...

The dynamics of a conducting laser ablated carbon plume flow in the ablation furnace typical for nanoparticle synthesis is investigated by numerical modeling. The effect of magnetic field on the flow is accounted through the Lorentz body force. The study begins with benchmark calculations of two simple test cases, the Kelvin-Helmholtz ...

The effect of ambient air pressure on the redeposition of debris, ablated from the zinc borosilicate glass target using 6 ns, 266 nm laser pulses, has been studied for incident fluences of 3-18 J/cm{sup 2}. Measurements were carried out in air at pressures ranging from 10-750 Torr. Scanning electron microscopy and optical microscope observations of the target surface were made ...

Investigations on the laser irradiation effects on gold are explored in terms of plasma-plume dynamics and morphological and crystallographic changes. Annealed 4N gold samples were irradiated with a Q-switched Nd:YAG laser (53 mJ, 21 MW, 532 nm, and pulse width 6-8 ns) for plume dynamics using 10-ns gated fast photography. A Q-switched pulsed Nd:YAG laser ...

A simple effort using molecular beam data to compare the results of two different transient free molecule point source models was performed, motivated by a desire to determine the utility of such formulations for a variety of time-dependent applications. These models are evaluated against effusive molecular beam time-of-flight data, as well as behavior observed in pulsed laser ...

We discuss the ablation of aluminum plasma using picosecond pulsed laser in vacuum and in ambient atmosphere of nitrogen. The plume dynamics of picosecond and nanosecond laser-ablated plumes in ambient atmosphere is discussed. The degree of polarization is measured using optical emission spectroscopy for the Al III ...

... A wide array of concepts will require the expansion of propellant gases through microscale nozzles. ... [7] The Reynolds number at a nozzle throat is ...

Laser ablation particle plume compositions are characterized using inductively coupled plasma mass spectrometry (ICP/MS). This study evaluates the mass response characteristics peculiar to ICP/MS detection as a function of laser fluence and frequency. Eva...

Page 1. Electronic State Distributions of Y Ba2Cu3O7�x Laser Ablated Plumes DISSERTATION Patrick D. Kee, Lieutenant Colonel, USAF ...

This paper presents an updated review of studies on Ablative Laser Propulsion conducted by the Laser Propulsion Group (LPG) at the University of Alabama in Huntsville. In particular, we describe the experimental technique developed for determination of specific impulses from plasma plume imaging with an intensified CCD camera.

Various physics and computational approaches have been developed to globally characterize phenomena important for film growth by pulsed-laser deposition of materials. These include thermal models of laser-solid target interactions that initiate the vapor plume, plume ionization and heating through laser absorption beyond local thermodynamic equilibrium ...

and hydrothermal or impact events. .... angle optical measurement will determine total turbidity. Climate history ... to minimize plume induced surface ablation. ...

by Laser Ablation Atomic Fluorescence Spectroscopy. Gary De Boer. .... Atomic fluorescence spectroscopy is an extremely sensitive means of ...

Measurements of the angle-dependent ablation rates of polymers that have applications in microdevice fabrication are reported. A simple model based on Beer's law, including plume absorption, is shown to give good agreement with the experimental findings for polycarbonate and SU8, ablated using the 193 and 248 nm excimer ...

Measurements of the angle-dependent ablation rates of polymers that have applications in microdevice fabrication are reported. A simple model based on Beer's law, including plume absorption, is shown to give good agreement with the experimental findings for polycarbonate and SU8, ablated using the 193 and 248 nm excimer lasers, ...

The pulsed laser deposition of YBa2Cu3O7?x targets by excimer laser at fluences of 4-10 J cm?2 in low pressure oxygen backgrounds yields emissive plumes with kinetic energies of 50-200 eV, driving the formation of a shock front with Mach numbers of M = 10-50. The propagation of the shock front is independent of atomic species and adequately characterized by the Sedov-Taylor ...

Several physics and computational approaches have been developed to globally characterize phenomena important for film growth by pulsed laser deposition of materials. These include thermal models of laser-solid target interactions that initiate the vapor plume; plume ionization and heating through laser absorption beyond local thermodynamic equilibrium ...

A time resolved imaging study of pulsed laser ablated Fe and Al plasma plumes with specific interest in the splitting of plumes into the slow and fast moving components as they expand through the background argon gas at different pressures is reported. The material ablation was achieved using a Q-switched Nd:YAG ...

To study the phase transformation mechanism and gas dynamic process for the laser-ablated plume, direct and indirect evidences of potential laser ablation mechanisms were sought experimentally and analytically. Two phase transformation mechanisms, normal vaporization and phase explosion, were introduced as the laser ...

Our studies of laser pulsed deposition of thin films, using 20-ns second-harmonic Nd:YAG laser operated at a few GW/cm{sup 2}, show that introduction of an obstacle like a grid screen into ablation plume with typical density 10{sup 18} cm{sup -3} and temperature 3 eV substantially affects dynamics of plasma expansion and results in ...

We have assessed the influence of viscous and adiabatic heatings on the transient development of plumes by employing the time-dependent convection equations in the extended-Boussinesq limit. Both temperature-dependent and temperature- and pressure-dependent viscosities are employed. For constant thermal expansion of coefficient we find the vigor of ...

A new concept of pulse laser ablation target were proposed. The idea is two-fold; that is, the target material to be ablated is a very thin layer deposited on a surface of some substrate material. As the substrate material, we will choose a transparent material like polymer or glass. Through the transparent material, a pulse laser beam is focused onto the ...

Free running Er:YAG lasers are used for a precise tissue ablation in various clinical application as, for example, laser skin resurfacing. The ablated material is ejected from the tissue surface in the direction of the incident laser beam. We investigated the influence of the shielding by the ablation plume on the ...

It has been generally believed in literature that in nanosecond laser ablation, the condensed substrate phase contributes mass to the plasma plume through surface evaporation across the sharp interface between the condensed phase and the vapor or plasma phase. However, this will not be true when laser intensity is sufficiently high. In this case, the ...

Laser ablation of bulk high-temperature superconductor (HTS) material provides a useful means of producing high-quality HTS thin films. Mass spectrometric probes of the ablation plume provide a microscopic understanding of the ablation event and plume development as well as providing a process ...

The precise characterization of plasmas generated by laser irradiation is needed for the development of ion sources. As the characteristic parameters of the expanding plasma vary with both the distance and the time, an experimental study of their evolution is appropriate for a deeper knowledge of the plasma. The purpose of this work is to study the same characteristics of laser plasma produced by ...

Combined diagnostic measurements are employed to characterize the penetration of energetic ablation plumes through background gases during a key transitional regime in which the ion flux is observed to split into distinct fast and slowed components. This ...

Laser plasmas were generated by ablation of aluminum targets via a Nd:YAG glass laser, of pulse energy 0.8 J, and duration 15 ns (full width at half maximum) at the fundamental wavelength (1.064 ?m). Emission lines in the wavelength range of 27-32 nm (45-37.8 eV) were mapped over a spatial range extending out 1.8 mm from the target surface and for a temporal range of 42 ns ...

A cerium oxide sample was ablated by 2nd harmonic radiation of Nd:YAG laser at a power density of 0.1 GW/cm2. Time evolution of the ablation plume was investigated by laser absorption time-of-flight (TOF) measurement. It was found that the ablated ionic plume in vacuum consisted of two ...

We report high-order harmonic generation from doubly charged ions in laser-ablation plasma produced by different prepulse intensities. At the prepulse intensity of 3.5x10{sup 10} W cm{sup -2}, harmonics up to the 63rd order (12.62 nm wavelength, 98.3 eV photon energy) were obtained by using a laser-ablation titanium plume. From ...

Experimental and theoretical studies on laser ablation of polymers (PMMA, polyimide) have been performed in a wide range of CO2-laser fluences. Evolution of polymer laser plume in air has been investigated with simultaneous registration of radiation spectra of the ablation products, spatial dynamics of plasma flare, and temporal ...

We present comprehensive experimental and theoretical studies of poly(methyl methacrylate) (PMMA) ablation by single pulses of 9.17 �m laser radiation in a wide range of fluences. Ablation was carried out in a quartz cell through which nitrogen under atmospheric pressure was pumped. The composition of the ablation products was ...

The transport dynamics of laser-ablated neutral/plasma plumes are of significant interest for film growth by pulsed-laser deposition of materials since the magnitude and kinetic energy of the species arriving at the deposition substrate are key processing parameters. Dynamical calculations of plume propagation in vacuum and in ...

The LaserProbe Inductively Coupled Plasma Mass Spectrometry (LP-ICP-MS) has shown great potential to precisely and quickly determine trace element compositions of minerals in situ at a scale of [le]60 [mu]m. However, standardization is complicated, due to the lack of matrix-matched, homogeneous mineral standards. In this study, a nonmatrix matched calibration standard, the NIST 612 silicate glass, ...

Femtosecond laser ablation and plume evolution of aluminum is investigated for various inhomogeneous laser pulses. For the simulations of the atoms the molecular dynamics code IMD is used. The ablated gas-phase is scanned by a cluster algorithm (DBSCAN), from which we gain a cluster size distribution of the ablated ...

This project involved a systematic study to apply newly discovered isotopic enrichment effects in laser ablation plumes to the fabrication of isotopically engineered thin films, superlattices, and nanostructures. The approach to this program involved using ultrafast lasers as a method for generating ablated plasmas that have ...

This paper reports ablation experiments on porcine corneal tissue using the Vanderbilt Mark III Free Electron Laser (FEL) and a tabletop Raman-shifted Alexandrite laser. These experiments were designed to test previous models that suggested wavelength and intensity dependent ablation mechanisms. In one test, we compare ablation ...

Ablation of gold nanoparticle films on polymer was explored using a nanosecond pulsed laser, with the goal to achieve feature size reduction and functionality not amenable with inkjet printing. The ablation threshold fluence for the unsintered nanoparticle deposit was at least ten times lower than the reported threshold for the bulk film. This could be ...

ablation and the direct simulation Monte Carlo (DSMC) method for simulation of the multi-component ablation description, direct simulation Monte Carlo (DSMC) [18], is chosen for extending the MD breathing sphere model into the larger scale. In order to adopt the results of MD simulation as input for the DSMC calculation, we have

The propagation of laser-induced shockwaves from ablation inside of cavities was determined from time-resolved shadowgraph images. The temperature and electron number density of the laser-induced plasma was determined from spectroscopic measurements. These properties were compared to those for laser ablation on the flat surface under the same energy and ...

There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface ...

Hook spectroscopy has been used to determine the absolute number density of ground state copper atoms in laser-ablated plasma plumes. An ablation laser power flux of (approximately) 1.5 GW/cm(sup 2) is applied to a solid copper target in a background gas,...

Femtosecond laser ablation of gallium arsenide investigated with time- of-flight mass spectroscopy laser-induced ablation of gallium arsenide using time-of-flight mass spectroscopy. At the ablation into a collisional expansion process. Above the ablation threshold, the behavior of gallium ...

A study was made of the cooling of the laser induced vapor plume in background air. The temperature and size variations of the vapor plume were determined from spectroscopic measurements during the first few tens of microseconds after the laser pulse. Experiments were carried out over a range of laser spot sizes and energies. The energy transport by ...

... from a hybrid particle-in-cell model (AQUILA) with Monte Carlo collisions to data obtained from the plume of Busek 600W Hall thruster (BHT-HD-600 ...

12 results ... A turbulent CFD analysis was conducted for jet plumes of isolated ...... supersonic blunt-base projectile with a bow shock, expansion fan, and tail shock ...

Also, this study is the first known jet plume sonic boom CFD study in which ..... a bow shock, expansion fan, and tail shock (for example, see reference 15). ...

Laser Induced Breakdown Spectroscopy LIBS is a fast non-contact technique for the analysis of the elemental composition using spectral information of the emission from a laser-induced plasma. For the LIBS studies in this thesis the focus has been in using very low energy, microjoule pulses in order to give high spatial resolution and minimize the laser system requirements. This is a regime that we ...

When a pulsed laser beam strikes the surface of an absorbing material, ultrasonic waves are generated due to thermoelectric expansion and, at higher laser power densities, ablation of the material. These sound generation mechanisms have been the subject o...

The objective of this program was to determine thermal conductivity, specific heat, thermal expansion and density to 4500F on well-defined samples of charred phenolic-carbon and phenolic-graphite ablators. Methods were to be established for characterizing...

The expansion of laser-ablated copper into room temperature helium to saturation and the subsequent copper condensation is analyzed. At saturation, the copper number density is about three orders of magnitude less than the helium number density. Saturatio...

Laser ablation of aluminum metal with 1 ns, 800 nm pulse at low radiant exposures was investigated in air (dry) and water (wet) environments. Compared to dry ablation, an approximately eight times increase in material removal rate was associated with wet ablation. Based on optical reflectance and scanning electron microscope images, ...

Laser ablation of aluminum metal with 1 ns, 800 nm pulse at low radiant exposures was investigated in air (dry) and water (wet) environments. Compared to dry ablation, an approximately eight times increase in material removal rate was associated with wet ablation. Based on optical reflectance and scanning electron microscope images, ...

We report the effect of 'plasma pipe' formation on pulsed laser ablation of organic polymers in air under normal conditions. Ablation of polymers (PMMA, polyimide) is carried out in a wide range of CO2 laser fluences with special attention to plasma formation in the ablation products. Evolution of laser ablation ...

Laser ablation has proven to be an effective method for generating nanoparticles; particles are produced in the laser induced vapor plume during the cooling stage. To understand the in-situ condensation process, a series of time resolved light scattering images were recorded and analyzed. Significant changes in the condensation rate and the shape of the ...

A femtosecond laser pulse with power density of 10{sup 13} to 10{sup 14} W/cm{sup 2} incident on a metal target causes ablation and ejection of the surface layer. The ejected laser plume has a complicated structure. At the leading front of the plume, there is a spall layer where the material is in a molten state. The spall layer is a ...

The plumes accompanying 1064 nm nanosecond pulsed laser ablation of barium in vacuum at three moderate incident laser fluences in the range of 5.3-10.8 J/cm2 have been studied using both wavelength and time resolved optical emission spectroscopy and time-of-flight laser-induced fluorescence. Neutral atoms and both singly and doubly charged monatomic ...

Laser ablation particle plume compositions are characterized using inductively coupled plasma mass spectrometry (ICP/MS). This study evaluates the mass response characteristics peculiar to ICP/MS detection as a function of laser fluence and frequency. Evaluation of the ICP/MS mass response allows deductions to be made concerning how representative the ...

Laser ablation particle plume compositions are characterized using inductively coupled plasma mass spectrometry (ICP/MS). This study evaluates the mass response characteristics peculiar to ICP/MS detection as a function of laser fluence and frequency. Evaluation of the ICP/MS mass response allows deductions to be made concerning how representative the ...

The emission spectrum of the 3?i-3?i (0-0) AlN band and some N+ and N emission lines have been studied in the visible region for the laser ablated plumes. The Stark-shift and Stark broadening were observed. The component species in the ablated plumes were analyzed by time of flight mass spectroscopy. The electron ...

We have successfully demonstrated intensity enhancement of a single high-order harmonic at a wavelength of 46.76 nm by using low-ionized tin ions in a laser-ablation plume as the nonlinear medium. The ablation plume was produced by irradiating a solid tin target with a 10 mJ energy picosecond laser pulse. Strong ...

We have successfully demonstrated intensity enhancement of a single high-order harmonic at a wavelength of 46.76 nm by using low-ionized tin ions in a laser-ablation plume as the nonlinear medium. The ablation plume was produced by irradiating a solid tin target with a 10 mJ energy picosecond laser pulse. Strong ...

With an interest in pulsed laser deposition and remote spectroscopy techniques, we explore here the potential of laser pulses temporally tailored on ultrafast time scales to control the expansion and the excitation degree of various ablation products including atomic species and nanoparticulates. Taking advantage of automated pulse-shaping techniques, an ...

With an interest in pulsed laser deposition and remote spectroscopy techniques, we explore here the potential of laser pulses temporally tailored on ultrafast time scales to control the expansion and the excitation degree of various ablation products including atomic species and nanoparticulates. Taking advantage of automated pulse-shaping techniques, an ...

Laser-material interaction of powerful (up to a terawatt) ultrashort (several picoseconds or shorter) laser pulses and laser-induced effects were investigated theoretically in this dissertation. Since the ultrashort laser pulse (USLP) duration time is much smaller than the characteristic time of the hydrodynamic expansion and thermal diffusion, the interaction occurs at a ...

... Research Laboratory at Edwards AFB by Photonics Associates of ... µLPT T-mode with copper probe ... evident with the higher ion density and ionization ...

A computer program was developed from an existing approximate method for determining the profile of a free expansion jet emanating into a quiescent atmosphere. Inclusion of a scale correlation factor was also a necessary addition to the theory to achieve ...

... A wide array of concepts will require the expansion of propellant gases through microscale nozzles. ... [7] The Reynolds number at a nozzle throat is ...

... by using the inverted Boltzmann equation: ... Nevertheless, source model information including this second ... in Figure 5. Using a curve fitting algorithm ...