scholarly journals Microcolumn development on titanium by multipulse laser irradiation in nitrogen

2003 ◽  
Vol 18 (9) ◽  
pp. 2228-2234 ◽  
Author(s):  
E. György ◽  
A. Pérez del Pino ◽  
P. Serra ◽  
J. L. Morenza
Keyword(s):  
Laser Irradiation ◽  
Crystalline State ◽  
Laser Intensity ◽  
Anatase Phase ◽  
Target Material ◽  
Single Pulse ◽  
Laser Pulses ◽  
Nitrogen Atmosphere ◽  
X Ray ◽  
Melting Threshold

We report the growth of titanium nitride microcolumns under multipulse Nd:yttrium aluminum garnet (λ = 1.064 μm, τ ∼ 300 ns, ν = 30 kHz) laser irradiation of titanium targets in nitrogen atmosphere. The laser intensity value was chosen below the single-pulse melting threshold of titanium. The evolution with the number of laser pulses of the target morphology, crystalline state, and chemical composition at the surface as well as in depth were investigated by scanning electron microscopy, x-ray diffractometry, Raman spectroscopy, and wavelength dispersive x-ray spectroscopy. Under the action of the laser pulses, during progressive surface nitridation, an initial rippled morphology developed, which evolved with further irradiation to TiN microcolumns. In-depth investigations showed a granular zone beneath the surface consisting of rutile and anatase phase TiO2, followed by a compact needlelike layer of titanium until the interface with the unaffected target material.

scholarly journals Laser-Induced Growth of Titanium Nitride Microcolumns on Biased Titanium Targets

2005 ◽  
Vol 20 (1) ◽  
pp. 62-67 ◽  
Author(s):  
E. György ◽  
A. Pérez del Pino ◽  
P. Serra ◽  
J.L. Morenza
Keyword(s):  
Bias Voltage ◽  
Single Pulse ◽  
Laser Pulses ◽  
High Repetition Rate ◽  
Applied Bias ◽  
Applied Bias Voltage ◽  
Surface Microrelief ◽  
High Repetition ◽  
Melting Threshold ◽  
Biased Samples

Titanium targets with a bias voltage ranging from −500 to +500 V were submitted to multipulse high repetition rate Nd:yttrium aluminum garnet (YAG; λ = 1.064 μm, τ ∼ 300 ns, ν = 30 kHz) laser irradiations in nitrogen at intensity values below the single-pulse melting threshold. The morphology of the TiN structures formed under the cumulative action of the laser pulses on the surface of the unbiased and biased targets was investigated by profilometry and scanning electron microscopy. Under these irradiation conditions, a specific columnar surface microrelief developed. The height of the microcolumns reached about 10–15 μm, and their diameter about 1–2 μm. The development of TiN microcolumns was enhanced by the applied bias voltage. The enhancement in the negative biased samples was stronger than that in the positive biased ones.

Time-Resolved X-Ray Studies During Pulsed-Laser Irradiation of Ge

1984 ◽  
Vol 35 ◽  
Author(s):  
J.Z. Tischler ◽  
B.C. Larson ◽  
D.M. Mills
Keyword(s):  
Melting Point ◽  
Laser Irradiation ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
High Energy ◽  
Measured Temperature ◽  
Time Resolved ◽  
Synchrotron Source ◽  
X Ray ◽  
Pulsed Laser Irradiation

ABSTRACTSynchrotron x-ray pulses from the Cornell High Energy Synchrotron Source (CHESS) have been used to carry out nanosecond resolution measurements of the temperature distrubutions in Ge during UV pulsed-laser irradiation. KrF (249 nm) laser pulses of 25 ns FWHM with an energy density of 0.6 J/cm2 were used. The temperatures were determined from x-ray Bragg profile measurements of thermal expansion induced strain on <111> oriented Ge. The data indicate the presence of a liquid-solid interface near the melting point, and large (1500-4500°C/pm) temperature gradients in the solid; these Ge results are analagous to previous ones for Si. The measured temperature distributions are compared with those obtained from heat flow calculations, and the overheating and undercooling of the interface relative to the equilibrium melting point are discussed.

scholarly journals Multiple application X-ray imaging chamber for single-shot diffraction experiments with femtosecond X-ray laser pulses

2014 ◽  
Vol 47 (1) ◽  
pp. 188-197 ◽  
Author(s):  
Changyong Song ◽  
Kensuke Tono ◽  
Jaehyun Park ◽  
Tomio Ebisu ◽  
Sunam Kim ◽  
...  
Keyword(s):  
Free Electron ◽  
Single Pulse ◽  
Laser Pulses ◽  
Atomic Scale ◽  
Single Shot ◽  
X Rays ◽  
Structural Investigations ◽  
X Ray ◽  
Multiple Application ◽  
X Ray Imaging

X-ray free-electron lasers (XFELs) provide intense (∼1012 photons per pulse) coherent X-rays with ultra-short (∼10−14 s) pulse lengths. X-rays of such an unprecedented nature have introduced new means of atomic scale structural investigations, and discoveries are still ongoing. Effective use of XFELs would be further accelerated on a highly adaptable platform where most of the new experiments can be realized. Introduced here is the multiple-application X-ray imaging chamber (MAXIC), which is able to carry out various single-pulse diffraction experiments including single-shot imaging, nanocrystallographic data acquisition and ultra-fast pump–probe scattering for specimens in solid, liquid and gas phases. The MAXIC established at the SPring-8 ångström compact free-electron laser (SACLA) has demonstrated successful applications in the aforementioned experiments, but is not limited to them. Also introduced are recent experiments on single-shot diffraction imaging of Au nanoparticles and serial crystallographic data collection of lysozyme crystals at SACLA.

scholarly journals Experimental and numerical study of ultra-short laser-produced collimated Cu Kα X-ray source

2017 ◽  
Vol 35 (3) ◽  
pp. 442-449 ◽  
Author(s):  
R. Rathore ◽  
V. Arora ◽  
H. Singhal ◽  
T. Mandal ◽  
J.A. Chakera ◽  
...  
Keyword(s):  
Laser Intensity ◽  
Numerical Study ◽  
Low Cost ◽  
Laser Pulses ◽  
Photon Flux ◽  
X Rays ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Short Laser Pulses

AbstractKα X-ray sources generated from the interaction of ultra-short laser pulses with solids are compact and low-cost source of ultra-short quasi-monochromatic X-rays compared with synchrotron radiation source. Development of collimated ultra-short Kα X-ray source by the interaction of 45 fs Ti:sapphire laser pulse with Cu wire target is presented in this paper. A study of the Kα source with laser parameters such as energy and pulse duration was carried out. The observed Kα X-ray photon flux was ~2.7 × 108 photons/shot at the laser intensity of ~2.8 × 1017 W cm−2. A model was developed to analyze the observed results. The Kα radiation was coupled to a polycapillary collimator to generate a collimated low divergence (0.8 mrad) X-ray beam. Such sources are useful for time-resolved X-ray diffraction and imaging studies.

scholarly journals A Mechanism for Inducing Compressive Residual Stresses on a Surface by Laser Peening without Coating

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 816 ◽  
Author(s):  
Yuji Sano ◽  
Koichi Akita ◽  
Tomokazu Sano
Keyword(s):  
Single Pulse ◽  
Laser Pulses ◽  
Mechanical Effect ◽  
Intense Laser ◽  
Laser Peening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intense Laser Pulses ◽  
Laser Peening Without Coating ◽  
Compressive Residual Stresses

Laser peening without coating (LPwC) involves irradiating materials covered with water with intense laser pulses to induce compressive residual stress (RS) on a surface. This results in favorable effects, such as fatigue enhancement; however, the mechanism underlying formation of the compressive RS is not fully understood. In general, tensile RS is imparted on the surface of the material due to shrinkage after heating by laser irradiation. In this study, we assessed the thermo-mechanical effect of single laser pulse irradiation and introduce a phenomenological model to predict the outcome of LPwC. To validate this model, RS distribution across the laser-irradiated spot was analyzed using X-ray diffraction with synchrotron radiation. In addition, the RS was evaluated across a line and over an area, following irradiation by multiple laser pulses with partial overlapping. Large tensile RSs were found in the spot irradiated by the single pulse; however, compressive RSs appeared around the spot. In addition, the surface RS state shifted to the compressive side due to an increase in overlap between neighboring laser pulses on the line and over the area of irradiation. The compressive RSs around a subsequent laser spot effectively compensated the tensile component on the previous spot by controlling the overlap, which may result in compressive RSs on the surface after LPwC.

Interface Temperatures and Temperature Gradients in Silicon During Pulsed Laser Irradiation

1988 ◽  
Vol 100 ◽  
Author(s):  
B. C. Larson ◽  
J. Z. Tischler ◽  
D. M. Mills
Keyword(s):  
Heat Flow ◽  
Laser Irradiation ◽  
Thermal Strain ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Temperature Gradients ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Gradients ◽  
Pulsed Laser Irradiation

ABSTRACTNanosecond-resolution x-ray diffraction has been used to measure the interface and lattice temperatures of silicon during rapid, pulsed-laser induced melting and regrowth in silicon. Measurements have been carried out on <100> and <111> oriented silicon using the (100) and (111) reflections to measure the thermal strain during 30 ns, 1.1 J/cm2 KrF laser pulses. The results indicate overheating to be low (< 2 K/m/s) for both orientations with undercooling rates of 5.6 K/m/s and 11.4 K/m/s for the <100> and <111> orientations, respectively. Observations of higher than expected temperature gradients below the liquidsolid interface have been discussed in terms of restricted heat flow under high gradients.

scholarly journals X-ray spectroscopy observation of fast ions generation in plasma produced by short low-contrast laser pulse irradiation of solid targets

2007 ◽  
Vol 25 (2) ◽  
pp. 267-275 ◽  
Author(s):  
A.YA. Faenov ◽  
A.I. Magunov ◽  
T.A. Pikuz ◽  
I. YU. Skobelev ◽  
S.V. Gasilov ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Laser Intensity ◽  
Laser Pulses ◽  
Intense Laser ◽  
Low Contrast ◽  
X Ray ◽  
Fast Ions ◽  
Self Focusing ◽  
Short Laser Pulses ◽  
Charged Ions

X-ray spectra of plasma produced by the interaction of Ti:Sa laser pulses (duration from 60 fs to 1 ps, and energy from 15 mJ to 128 mJ) with foil and solid Teflon and AL targets are investigated. It is shown experimentally and theoretically that the use of low contrast (10−2 – 10−4) short laser pulses, essentially promotes the conditions for generation of fast multi-charged ions. This effect is caused by self-focusing of the main laser pulse in a preplasma produced by intense laser prepulses. Modeling of the observed spectral line shape gives evidence of a considerable (about 3%) amount of multi-charged He-like F ions with energy E ∼ 1 MeV at rather low values of laser intensity IL ≈ 6 × 1016 W cm−2.

scholarly journals Generation of X rays and energetic ions from superintense laser irradiation of micron-sized Ar clusters

2004 ◽  
Vol 22 (3) ◽  
pp. 215-220 ◽  
Author(s):  
Y. FUKUDA ◽  
Y. AKAHANE ◽  
M. AOYAMA ◽  
N. INOUE ◽  
H. UEDA ◽  
...  
Keyword(s):  
Laser Irradiation ◽  
Laser Pulses ◽  
Photon Flux ◽  
X Rays ◽  
Resonant Line ◽  
Energetic Ions ◽  
X Ray ◽  
Multiply Charged ◽  
Ion Kinetic Energy ◽  
Isochoric Heating

High-resolutionK-shell spectra of a plasma created by superintense laser irradiation of micron-sized Ar clusters have been measured with an intensity above 1019W/cm2and a pulse duration of 30 fs. The total photon flux of 2 × 108photons/pulse was achieved for Heα1resonant line of Ar (λ = 3.9491 Å, 3.14 keV). In parallel with X-ray measurements, energy distributions of emitted ions have been measured. The multiply charged ions with kinetic energies up to 800 keV were observed. It is found that hot electrons produced by high contrast laser pulses allow the isochoric heating of clusters and shift the ion balance toward the higher charge states, which enhances both the X-ray line yield of the He-like argon ion and the ion kinetic energy.

scholarly journals EXAFS Spectroscopy by Continuum Soft X-ray Emission from a Short Pulse Laser-produced Plasma

1986 ◽  
Vol 39 (2) ◽  
pp. 253 ◽  
Author(s):  
GJ Tallents ◽  
B Luther-Davies ◽  
MA Horsburgh
Keyword(s):  
Laser Intensity ◽  
Short Pulse ◽  
Laser Pulses ◽  
Exafs Spectroscopy ◽  
Qualitative Model ◽  
Wavelength Band ◽  
Detector Plane ◽  
X Ray ◽  
Short Pulse Laser ◽  
Laser Produced Plasma

The use of a laser-produced plasma created by low ener~y (E :::;; 61), ps duration laser pulses as the X-ray source for EXAFS spectroscopy in the 3-8 A wavelength band is investigated. We consider the various factors that affect the X-ray flux at the detector plane and investigate ways of optimizing that flux. A simple qualitative model has been used to describe the way in which the source intensity scales with parameters�such as the laser intensity. Practical problems associated with the implementation of the various different X-ray dispersive elements and detectors are discussed.

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