scholarly journals Study of second harmonic emissions for characterization of laser–plasma X-ray sources

1998 ◽  
Vol 16 (2) ◽  
pp. 397-404 ◽  
Author(s):  
A. Giulietti ◽  
C. Beneduce ◽  
T. Ceccotti ◽  
D. Giulietti ◽  
L.A. Gizzi ◽  
...  
Keyword(s):  
Laser Beam ◽  
Transport Process ◽  
Energy Transport ◽  
Laser Light ◽  
Second Harmonic ◽  
Target Position ◽  
Laser Pulses ◽  
Strongly Correlated ◽  
X Ray

An investigation of second harmonic (SH) and X-ray emissions from Al plasmas produced by 3-ns, 1.064-μm laser pulses at 1014 W/cm2 is reported. The SH and X-ray yields are strongly correlated as a function of the target position with respect to the laser beam focus. The SH originates from the underdense coronal plasma and has a filamentary source, while the X-ray source is uniform. The results suggest that, although the X-ray emission is significantly enhanced by the filamentation of the laser light in the corona, there is a smoothing effect in the energy transport process toward the overdense region.

Characterization of columns grown during KrF laser micromachining of Al2O3–TiC ceramics

2003 ◽  
Vol 18 (5) ◽  
pp. 1123-1130 ◽  
Author(s):  
V. Oliveira ◽  
R. Vilar
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Laser Pulses ◽  
Formation Mechanisms ◽  
X Ray ◽  
Reducing Conditions ◽  
Transmission Electron ◽  
Column Formation ◽  
Krf Laser

This paper aims to contribute to the understanding of column formation mechanisms in Al2O3–TiC ceramics micromachined using excimer lasers. Chemical and structural characterization of columns grown in Al2O3–TiC composite processed with 200 KrF laser pulses at 10 J/cm2 was carried out by scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction analysis. Fully developed columns consist of a core of unprocessed material surrounded by an outer layer of Al2TiO5, formed in oxidizing conditions, and an inner layer, formed in reducing conditions, composed of TiC and Al3Ti or an AlTi solid solution. Possible mechanisms of column formation are discussed.

Fabrication and Characterization of Si Nano-Columns by Femtosecond Laser

2012 ◽  
Vol 16 ◽  
pp. 15-20 ◽  
Author(s):  
Omid Tayefeh Ghalehbeygi ◽  
Vural Kara ◽  
Levent Trabzon ◽  
Selcuk Akturk ◽  
Huseyin Kizil
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Laser Beam ◽  
Chemical Etching ◽  
Silicon Surface ◽  
Laser Pulses ◽  
Laser Beam Profile ◽  
Fs Laser ◽  
Fabrication And Characterization

We fabricated Si Nano-columns by a femtosecond laser with various wavelengths and process parameters, whilst the specimen was submerged in water. The experiments were carried out by three types of wavelengths i.e. 1030 nm, 515nm, 343nm, with 500 fs laser pulses. The scales of these spikes are much smaller than micro spikes that are constructed by laser irradiation of silicon surface in vacuum or gases like SF6, Cl2. The Si nano-columns of 300 nm or less in width were characterized by SEM measurements. The formation of these Si Nano-columns that were revealed by SEM observation, indicates chemical etching with laser ablation occurred when surface exposed by laser beam. We observed 200 nm spikes height at the center of laser beam profile and the ones uniform in height at lateral incident area.

Characterization of ultrafast free-electron laser pulses using extreme-ultraviolet transient gratings

2018 ◽  
Vol 25 (1) ◽  
pp. 32-38 ◽  
Author(s):  
F. Capotondi ◽  
L. Foglia ◽  
M. Kiskinova ◽  
C. Masciovecchio ◽  
R. Mincigrucci ◽  
...  
Keyword(s):  
Arrival Time ◽  
Extreme Ultraviolet ◽  
Laser Pulses ◽  
Linear Process ◽  
Third Order ◽  
X Ray ◽  
High Pulse ◽  
Spectral Ranges ◽  
Pulse Energies

The characterization of the time structure of ultrafast photon pulses in the extreme-ultraviolet (EUV) and soft X-ray spectral ranges is of high relevance for a number of scientific applications and photon diagnostics. Such measurements can be performed following different strategies and often require large setups and rather high pulse energies. Here, high-quality measurements carried out by exploiting the transient grating process,i.e.a third-order non-linear process sensitive to the time-overlap between two crossed EUV pulses, is reported. From such measurements it is possible to obtain information on both the second-order intensity autocorrelation function and on the coherence length of the pulses. It was found that the pulse energy density needed to carry out such measurements on solid state samples can be as low as a few mJ cm−2. Furthermore, the possibility to control the arrival time of the crossed pulses independently might permit the development of a number of coherent spectroscopies in the EUV and soft X-ray regime, such as, for example, photon echo and two-dimensional spectroscopy.

Characterization of the 46.9-nm soft X-ray laser beam from a capillary discharge

2014 ◽  
Vol 117 (1) ◽  
pp. 131-139 ◽  
Author(s):  
S. Barnwal ◽  
Y. B. S. R. Prasad ◽  
S. Nigam ◽  
K. Aneesh ◽  
M. L. Sharma ◽  
...  
Keyword(s):  
Laser Beam ◽  
Capillary Discharge ◽  
X Ray

GROWTH AND CHARACTERIZATION OF A SEMIORGANIC NLO MATERIAL: L-HISTIDINE BARIUM CHLORIDE DIHYDRATE

2016 ◽  
Vol 2 (1) ◽  
pp. 26-30
Author(s):  
Beena T R
Keyword(s):  
Nonlinear Optical ◽  
Room Temperature ◽  
Vickers Microhardness ◽  
Second Harmonic ◽  
Barium Chloride ◽  
Nonlinear Optical Material ◽  
Solvent Evaporation Method ◽  
X Ray ◽  
Chloride Dihydrate

L-Histidine Barium Chloride dihydrate (LHBC), a semi organic nonlinear optical material was grown from aqueous solution by slow solvent evaporation method at room temperature.  The LHBC crystals were characterized by X-ray powder diffraction analysis.  The presence of functional groups was identified through Fourier Transform Infrared Spectroscopy.  Thermogravimetric and Differential Thermal Analysis confirm that the crystal is stable up to 269oC.  The mechanical properties of the grown crystals have been studied using Vickers microhardness test.  The second harmonic generation behavior of LHBC crystal was tested by Kurtz-Perry powder technique.

Preparation and Characterization of TiO2 Nanostructures for Catalytic CO2 Photoconversion

2011 ◽  
Vol 183 ◽  
pp. 89-94 ◽  
Author(s):  
Anna Iwulska ◽  
G. Sliwinski
Keyword(s):  
Active Surface ◽  
Laser Pulses ◽  
Point Of View ◽  
Deep Penetration ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Content Ratio ◽  
Photocatalytic Applications

The titanium dioxide target (99.7%) of 1 cm in dia was ablated in vacuum by laser pulses (6 ns) at 266 nm and at repetition rate of 10 Hz. During deposition the laser fluence between 1 and 3.5 J/cm2 and the O2 pressure from the range of 10-2 – 1 Pa were applied. The thin TiO2 films were deposited on glass substrate (1 × 1 cm2) heated up to 500 °C. The chemical composition of the film and samples produced by annealing were investigated by spectroscopic techniques (μ-Raman, EDX) and the structure, porosity and surface morphology were analysed by means of SEM and x-ray diffraction (XRD). The SEM inspection of the TiO2 thin film samples indicates that the obtained material is mostly crystalline. After annealing in O2 at 500 °C the structure characterized by the presence of both anatase and rutile phases is observed in the Raman spectra and confirmed by the XRD data. The phase content ratio depends on the O2 pressure applied. Results confirm that nanostructures produced in this way represent densely packed columns and promote deep penetration of guest particles such as CO2.The resulting large active surface is advantageous from the point of view of photocatalytic applications.

Characterization of an x-ray laser beam

2001 ◽  
Author(s):  
Sebastien Le Pape ◽  
Philippe Zeitoun ◽  
Jorge J. G. Rocca ◽  
Antoine Carillon ◽  
Pierre Dhez ◽  
...  
Keyword(s):  
Laser Beam ◽  
X Ray

scholarly journals Characterization of CuO thin films for gas sensing applications

2019 ◽  
Vol 14 (31) ◽  
pp. 1-12
Author(s):  
Jamal M. Rzaij
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Cupric Oxide ◽  
Laser Pulses ◽  
X Ray Diffraction ◽  
Energy Increase ◽  
Nano Structure ◽  
X Ray ◽  
Sensing Applications

Nanostructural cupric oxide (CuO) films were prepared on Si and glass substrate by pulsed laser deposition technique (PLD) using laser Nd:YAG, using different laser pulses energies from 200 to 600 mJ. The X-ray diffraction pattern (XRD) of the films showed a polycrystalline structure with a monoclinic symmetry and preferred orientation toward (111) plane with nano structure. The crystallite size was increasing with increasing of laser pulse energy. Optical properties was characterized by using UV–vis spectrometer in the wave lengthrange (200-1100) nm at room temperature. The results showed that the transmission spectrum decreases with the laser pulses energy increase. Sensitivity of NO2 gas at different operating temperatures, (50°C, 100°C, 150°C and 200°C) was calculated.

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