scholarly journals Effect of Laser Energy and Repetition Rate on Holmium Plasma Emission

2020 ◽  
Vol 18 (44) ◽  
pp. 98-108
Author(s):  
Nipras Nazeh Mahmoad ◽  
Mahmoad Shakir Mahmoad
Keyword(s):  
Laser Pulse ◽  
Pulse Energy ◽  
Repetition Rate ◽  
Laser Pulse Energy ◽  
Laser Energy ◽  
Emission Spectra ◽  
Maximum Intensity ◽  
Plasma Emission ◽  
Line Intensities ◽  
Pulse Energies

The holmium plasma induced by a 1064-nmQ-switched Nd:YAG laser in air was investigated. This work was done theoretically and experimentally.  Cowan code was used to get the emission spectra for different transition of the holmium target. In the experimental work, the evolution of the plasma was studied by acquiring spectral images at different laser pulse energies (600,650,700, 750, and 800 mJ). The repetition rates of (1Hz and 10Hz) in the UV region (200-400 nm). The results indicate that, the emission line intensities increase with increasing of the laser pulse energy and repetition rate. The strongest emission spectra appeared when the laser pulse energy is 800mJ and 10 Hz repetition rate at λ= 345.64nm, with the maximum intensity of 77000 counts.

scholarly journals Surface characterization of laser-induced molten area in micro-grooving of silicon by ultraviolet (UV) laser

2021 ◽  
Vol 2051 (1) ◽  
pp. 012003
Author(s):  
N S A Raman ◽  
I H W Nordin ◽  
M S A Majid ◽  
Z M Razlan ◽  
S S C Abdullah
Keyword(s):  
Laser Pulse ◽  
Pulse Energy ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Laser Pulse Energy ◽  
Scanning Speed ◽  
Pulse Repetition ◽  
Irradiation Condition ◽  
Uv Laser ◽  
High Pulse

Abstract The objective of this research is to understand the fundamental mechanisms that govern the formation of laser-induced molten area during the micro-grooved fabrication on silicon material. In this research work, micro grooves were fabricated on silicon wafer by using ultraviolet (UV) laser of 248nm wavelength. Influence of lasing parameters such as pulse duration, laser pulse energy and scanning speed on the surface of micro-grooved was characterized. It is found that, the width of the micro grooves become wider with increasing laser pulse energy when ultraviolet laser was irradiated on silicon material. On the other hand, heat affected zone (HAZ) can be found at the surface of micro groove line at high pulse energy, high pulse repetition rate and lower scanning speed irradiation condition. This is considered due to the excessive heat input of the laser irradiation condition. It is concluded that proper selection of laser processing parameters of pulse energy, E, pulse repetition rate, R p , and scanning speed is necessary to achieve high quality micro-grooves.

Evaluation of Alternative Preparation Methods for Failure Analysis at Modern Chip and Package Technologies

2001 ◽  
Author(s):  
A. Dübotzky ◽  
B. Krüger
Keyword(s):  
Laser Ablation ◽  
Laser Pulse ◽  
Failure Analysis ◽  
Pulse Energy ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Laser Pulse Energy ◽  
Preparation Methods ◽  
Silicon Thickness ◽  
Gold Wires

Abstract We evaluated laser ablation and sandblasting as preparation methods for package related failures and for backside analysis of ICs. With laser ablation we uncovered gold wedges on an internal board of a PLFBGA package without damage of the gold wires and the board metallization. This was possible by optimization of the laser pulse energy and the pulse repetition rate and by limitation of the ablation area. Sandblasting showed to be a gentle way for backside thinning down to 60 μm silicon thickness. For a surface smoothness sufficient for IR imaging a subsequent planarization treatment is necessary.

Fabrication and Characterization of Micro-Dent Produced by Laser Shock Peening on Zr-Based Bulk Metallic Glass

2016 ◽  
Vol 849 ◽  
pp. 14-21
Author(s):  
Yun Hu Zhu ◽  
Jie Fu ◽  
Chao Zheng ◽  
Zhong Ji
Keyword(s):  
Plastic Deformation ◽  
Laser Pulse ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Pulse Energy ◽  
Laser Pulse Energy ◽  
Laser Energy ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Shock Peening

A Zr41.2Ti13.8Cu12.5Ni10Be22.5 (vit1) bulk metallic glass was processed by Nd: Glass laser pulses with duration 30ns and energy in the range 20 to 30J. The surface morphology and surface micro-hardness of the vit1 metallic glass, treated with varying laser energy, had been studied in detail. Laser shock peening induced plastic deformation and caused a micro-dent to be generated on the vit1 surface. The optical profiling tests showed that laser pulse energy greatly influenced the diameter and depth of the micro-dents. The surface roughness which was caused by various laser pulse energy was assessed and characterized. The three-dimensional surface topography of the laser treated region on vit1 surfaces had been characterized. In addition the plastic deformation features were also studied.

scholarly journals Спектральные характеристики свечения поверхности частиц каменных углей во время воздействия лазерных импульсов в режиме свободной генерации

2020 ◽  
Vol 128 (12) ◽  
pp. 1898
Author(s):  
Б.П. Адуев ◽  
Д.Р. Нурмухаметов ◽  
Я.В. Крафт ◽  
З.P. Исмагилов
Keyword(s):  
Energy Density ◽  
Laser Pulse ◽  
Pulse Energy ◽  
Laser Pulse Energy ◽  
Emission Spectra ◽  
Radiation Energy ◽  
Laser Pulses ◽  
Radiation Energy Density ◽  
Pulse Energy Density ◽  
Coal Particles

In this work, we investigated the glow spectra of coal fractions with dimensions 63 μm directly during the action of neodymium laser pulses (120 μs). Depending on the radiation energy density H, the emission spectra have a different character. The glow at the minimum values ​​of the laser pulse energy density Hcr (1) is associated with the ignition of small coal particles (~ 1 μm) present in the fractions and the ignition of reactive microprotrusions on the surface of the larger coal particles. The glow spectra at this stage are of a non-thermal nature and are associated with the emission of molecules of volatile substances in the gas phase and the products of their oxidation. With an increase in the laser pulse energy density H, a thermal glow of the surface of larger coal particles is observed, which is described by the Planck formula at T = 3100 K. When H = Hcr (2) is reached, the surface of the coal particles is ignited during the action of the laser pulse. Contributions to the spectra are the glow of the surface of coal particles, emitted carbon particles, and the glow associated with the emission of excited molecules H2, H2O, CO2. With an increase in H> Hcr (2), the processes leading to the glow of coal particles during a laser pulse are similar to those described above for Hcr (2), but the glow intensity increases

Atom-Probe Tomographic Analyses of Hydrogen Interstitial Atoms in Ultrahigh Purity Niobium

2015 ◽  
Vol 21 (3) ◽  
pp. 535-543 ◽  
Author(s):  
Yoon-Jun Kim ◽  
David N. Seidman
Keyword(s):  
Laser Pulse ◽  
Thermal Energy ◽  
Pulse Energy ◽  
Laser Pulse Energy ◽  
Atom Probe ◽  
Atomic Scale ◽  
Hydrogen Atoms ◽  
Atomic Concentration ◽  
Pulse Energies ◽  
Concentration Ratios

AbstractAtomic-scale characterization of hydrogen and formation of niobium hydrides, using ultraviolet (wavelength=355 nm) picosecond laser-assisted local-electrode atom-probe tomography, was performed for ultrahigh purity niobium utilizing different laser pulse energies, 10 or 50 pJ/pulse or voltage pulsing. At 50 pJ/pulse, hydrogen atoms migrate onto the 110 and 111 poles as a result of stimulated surface diffusion, whereas they are immobile for <10 pJ/pulse or for voltage pulsing. Accordingly, the highest concentrations of H and NbH were obtained at 50 pJ/pulse. This is attributed to the thermal energy of the laser pulses being transferred to pure niobium specimens. Therefore, we examined the effects of the laser pulse energy being increased systematically from 1 to 20 pJ/pulse and then decreasing it from 20 to 1 pJ/pulse. The concentrations of H, H2, and NbH and the atomic concentration ratios H2/H, NbH/Nb, and Nb3+/Nb2+ were calculated with respect to the systematically changing laser pulse energies. The atomic concentration ratios H2/H and NbH/Nb are greater when decreasing the laser pulse energy than when increasing it, because the higher residual thermal energy after decreasing the laser pulse energy increases the mobility of H atoms by supplying sufficient thermal energy to form H2 or NbH.

scholarly journals INFLUENCE OF LASER ENERGY ON CDS NANO PARTIALS PREPARED BY LASER INDUCED PLASMA

2021 ◽  
Vol 03 (03) ◽  
pp. 69-76
Author(s):  
Hayim Ch, MAGID ◽  
Intesar Hato HASHIM ◽  
Kadhim A. AADIM
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Laser Pulse ◽  
Pulse Energy ◽  
Laser Pulse Energy ◽  
Laser Energy ◽  
Plasma Deposition ◽  
Hexagonal Structure ◽  
Structural Morphology ◽  
Laser Induced Plasma

In this work ,cadmium sulfide (CdS) thin films deposited on glass substrates using Nd-YAG laser wavelength (1064 nm) laser-induced plasma deposition technique (PLD). The structural, morphology and optical properties of these films have been described as a change in the effect of laser pulse energy ( ). The X-ray diffraction results show that s all samples were polycrystalline hexagonal structure and the crystalline size ghange with increasing of the laser energy. The optical properties results show that the transmittance of all deposited thin films decreases with increasing of laser pulse energy .As a result of the microscopic examination of the surface, it was found that the surface is uniform and the granular size increases with the increase of the laser power.

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