Excinier Laser Radiation Induced Rapid-Solidification of Alunjinumi and Aluminumi Alloys

1986 ◽  
Vol 80 ◽  
Author(s):  
G. Antony ◽  
P. R. Strutt
Keyword(s):  
Laser Radiation ◽  
Energy Density ◽  
Wave Structure ◽  
Incident Radiation ◽  
Surface Melting ◽  
Interesting Phenomenon ◽  
Radiation Induced ◽  
Excimer Laser Radiation ◽  
Multiple Pulses ◽  
Striking Effect

AbstractA study of the effects of high intensity excimer laser radiation (249nm.) of aluminum and an Al-Si alloy reveals a variety of intriguing surface topographical features. Important parameters determining these include the energy-density and the number of short-duration (≈22ns.) pulses. Specific attention has been devoted to determining the condition for the onset of surface melting, and the physical effects of further increasing the energy density. A study of the frozen-in surface wave structure has been used to determine the approximate solidification time and the solidification-front velocity. As well as overall surface melting, an interesting phenomenon is the localized melting occurring at precipitates which preferentially absorb the incident radiation. This phenomenon has been studied in an Al-Si alloy subjected to single and multiple pulses; the effect of the latter has been found to have a striking effect.

Pigmentation above the constitutive level: An indicator of excimer laser radiation-induced erythema in Koreans

2012 ◽  
Vol 39 (7) ◽  
pp. 608-612 ◽  
Author(s):  
Jee-Woong CHOI ◽  
Se-Young NA ◽  
Mi-Young CHUNG ◽  
Jung-Im NA ◽  
Chang-Hun HUH ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Excimer Laser ◽  
Radiation Induced ◽  
Excimer Laser Radiation

scholarly journals Observation of a comb-shaped filamentary plasma array under subcritical condition in 303-GHz millimetre-wave air discharge

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Masafumi Fukunari ◽  
Shunsuke Tanaka ◽  
Ryuji Shinbayashi ◽  
Yuusuke Yamaguchi ◽  
Yoshinori Tatematsu ◽  
...  
Keyword(s):  
Electric Field ◽  
Focal Point ◽  
Incident Beam ◽  
Wave Structure ◽  
Field Vector ◽  
Interesting Phenomenon ◽  
Millimetre Wave ◽  
Field Plane ◽  
Subcritical Condition ◽  
Air Discharge

AbstractGas breakdown in the millimetre-wave frequency band is an interesting phenomenon in nonlinear dynamics such as self-organized structure formation. We observed the transition between two types of filamentary plasma arrays in air discharge driven by a 303-GHz millimetre wave. Plasma is ignited at a parabolic mirror’s focal point in the overcritical condition. One array parallel to the electric field vector appears with a spacing of λ/4 at the focal point. Filaments then separate into plasma lumps ~10 μs after ignition. At 20 μs, a new comb-shaped array grows in the subcritical condition. Filaments are parallel to the incident beam with spacing of 0.96 λ and elongate towards the incident beam. This comb-shaped array appears only in the electric field plane; bulk plasma with a sharp vertex forms in the magnetic field plane. This array is created by a standing wave structure generated by waves diffracted from the plasma surface. Filamentary plasma array formations can influence the energy absorption by the plasma, which is important for engineering applications such as beamed energy propulsion.

Excitation of transitions between atomic or molecular energy levels by monochromatic laser radiation - II. Excitation under conditions of strictly inhomogeneous line broadening and mixed homogeneous and inhomogeneous broadening

1978 ◽  
Vol 362 (1708) ◽  
pp. 13-25 ◽  
Keyword(s):  
Laser Radiation ◽  
Line Width ◽  
Energy Levels ◽  
Incident Radiation ◽  
Exciting Radiation ◽  
Half Line ◽  
Line Broadening ◽  
Moment Matrix ◽  
Inhomogeneous Line Broadening ◽  
Inhomogeneous Line

The development with time of the excitation of a transition between two atomic or molecular energy levels under the influence of monochromatic laser radiation is examined under conditions of strictly inhomogeneous line broadening due to such causes as doppler shift arising from translational velocity. The ratio of the number of molecules, N 2 , in an excited state to the total number, N , is calculated for various ratios of the intensity parameter β ═ E 0 μ / ħ to the half line-width ∆ , where E 0 is the amplitude of the electric field in the incident radiation and is the dipole moment matrix element for the transition. Excitation functions obtained in a previous paper (I) for various values of the ratio γ/β , where γ is the half line-width in the absence of inhomo­geneous broadening, are used to obtain the variation of N 2 / N with time under conditions of mixed broadening for various values of the ratio γ/∆ and γ/β , when the exciting radiation is in exact resonance with the central frequency of the transition.

New surface modifications of polymer films with the excimer laser radiation

1993 ◽  
Author(s):  
Sylvain Lazare ◽  
Pascale Benet ◽  
Matthias Bolle ◽  
Philipe De Donato ◽  
Eric Bernardy
Keyword(s):  
Laser Radiation ◽  
Excimer Laser ◽  
Polymer Films ◽  
Surface Modifications ◽  
Excimer Laser Radiation

Bactericidal action of 308 nm excimer-laser radiation: An in vitro investigation

1998 ◽  
Vol 24 (12) ◽  
pp. 781-785 ◽  
Author(s):  
Matthias Folwaczny ◽  
Tim Liesenhoff ◽  
Norbert Lehn ◽  
Hans-Henning Horch
Keyword(s):  
Laser Radiation ◽  
Excimer Laser ◽  
Bactericidal Action ◽  
In Vitro Investigation ◽  
Excimer Laser Radiation

Photoablation Studies of Polymers, Quartz, and Semiconductors with Vacuum Ultraviolet Laser Radiation

1991 ◽  
Vol 236 ◽  
Author(s):  
Peter R. Herman ◽  
Boyi Chen ◽  
David J. Moore ◽  
Mark Canaga-Retnam
Keyword(s):  
Laser Radiation ◽  
Polymethyl Methacrylate ◽  
Thermal Damage ◽  
Vacuum Ultraviolet ◽  
Medical Industry ◽  
Surface Melting ◽  
Excimer Lasers ◽  
Ultraviolet Laser ◽  
Low Threshold ◽  
Microelectronics Industry

AbstractExcimer lasers sources of 193nm and 157 nm wavelength were used to obtain new photoablation etching rates for several materials of interest to the microelectronics industry. The harder 157nm radiation provided lower ablation rates and smaller threshold fluences for Polyimide and Polymethyl Methacrylate (PMMA) than with 193nm. For normally robust materials like quartz and Teflon (PTFE), the 157nm laser produced clean and smooth ablation sites with low threshold fluences of 620mJ/cm2 and 68mJ/cm2, respectively, features impossible to obtain with conventional excimer lasers at longer wavelengths. The data should help define new micromachining applications of these two materials for the electronic, optical or medical industry. Results are also reported for GaAs and InP based materials which are found to undergo moderate etch rates of 30-80nm/pulse at fluences of ∼3J/cm2, but suffer thermal damage and material segregation due to surface melting.

Excimer Laser Interaction with Metals

1992 ◽  
Vol 285 ◽  
Author(s):  
W.W. Duley ◽  
G. Kinsman
Keyword(s):  
Experimental Data ◽  
Laser Radiation ◽  
Excimer Laser ◽  
Metal Surfaces ◽  
Laser Pulses ◽  
Radiative Properties ◽  
Uv Laser ◽  
Laser Interaction ◽  
Excimer Laser Radiation

ABSTRACTExcimer laser radiation may be used to process metal surfaces in a variety of novel ways. The simplest of these involves the use of UV laser pulses for ablation. Ablation occurs as the result of both vaporization and hydrodynamical effects. Experimental data related to these processes will be discussed. In addition, it will be shown how specific irradiation regimes can yield metal surfaces with unique radiative properties.

DNA Damage in Cultured Human Skin Fibroblasts Exposed to Excimer Laser Radiation

1990 ◽  
Vol 96 (6) ◽  
pp. 898-902 ◽  
Author(s):  
Donata. Rimoldi ◽  
Alexandra C. Miller ◽  
Steven E. Freeman ◽  
Dvorit. Samid
Keyword(s):  
Dna Damage ◽  
Laser Radiation ◽  
Human Skin ◽  
Excimer Laser ◽  
Skin Fibroblasts ◽  
Human Skin Fibroblasts ◽  
Excimer Laser Radiation
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