Ultraviolet versus infrared: Effects of ablation laser wavelength on the expansion of laser-induced plasma into one-atmosphere argon gas

2012 ◽  
Vol 111 (5) ◽  
pp. 053301 ◽  
Author(s):  
Qianli Ma ◽  
Vincent Motto-Ros ◽  
Fabrice Laye ◽  
Jin Yu ◽  
Wenqi Lei ◽  
...  
Keyword(s):  
Laser Wavelength ◽  
Argon Gas ◽  
Laser Induced Plasma ◽  
Ablation Laser

Control of structures of deposited polymer films by ablation laser wavelength: Polyacrylonitrile at 308, 248, and 193 nm

1996 ◽  
Vol 79 (9) ◽  
pp. 7198-7204 ◽  
Author(s):  
Satoru Nishio ◽  
Tomonori Chiba ◽  
Akiyoshi Matsuzaki ◽  
Hiroyasu Sato
Keyword(s):  
Polymer Films ◽  
Laser Wavelength ◽  
Ablation Laser ◽  
193 Nm

scholarly journals EFFECT OF THICKNESS ON THE STRUCTURE AND OPTICAL PROPERTIES OF LASER-INDUCED PLASMA CDO THIN FILMS

2021 ◽  
Vol 03 (03) ◽  
pp. 41-50
Author(s):  
Hiyam Ch. MAJED
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Energy Gap ◽  
Plasma Deposition ◽  
Cadmium Oxide ◽  
Laser Wavelength ◽  
Dielectric Constants ◽  
Laser Induced Plasma ◽  
Glass Substrates ◽  
Cdo Thin Films

Thin films of cadmium oxide (CdO) deposited on glass substrates using Nd-YAG laser wavelength (alpha= 532 nm) and period time (10ns) via laser-induced plasma deposition technique (PLD). The structural properties of these films have been described as a change in thickness (200 , 400 ,and 1000) nm) at substrate temperature of (400 ° C) and energy flounce of (0.4 J / cm2). The X-ray diffraction results show that he mean size of crystallite measured using Scherer formula to adjust the thickness of 200 nm, 400 nm and 1000 nm of CdO thin films is 47 nm, 64 nm and 78 nm respectively .Also the optical properties which included transmittance, absorbance , energy gap and optical constant such as the Refractive index, extinction coefficient real and imaginary parts of dielectric constants were determined .

Dependence of the Ejection Velocities of Laser-Ablated Ions on the Laser Wavelength and Fluence

2009 ◽  
Vol 15 (2) ◽  
pp. 305-314 ◽  
Author(s):  
Chau-Wen Chou ◽  
Randall W. Nelson ◽  
Peter Williams
Keyword(s):  
Laser Fluence ◽  
Pulsed Laser ◽  
Laser Desorption ◽  
Laser Wavelength ◽  
Molecular Ions ◽  
Laser Desorption Ionization ◽  
Ablation Laser ◽  
The Matrix ◽  
Matrix Assisted Laser ◽  
Pulsed Laser Irradiation

Drift measurements of initial ejection velocities of matrix-assisted laser desorption/ionization matrix compounds have been made as a function of ablating laser wavelength and laser fluence. For pulsed laser irradiation just above the matrix ion appearance threshold, initial ejection velocities of protonated molecular ions of an anthranilic acid target increase from ∼ 1350 m/s to ∼ 1640 m/s (kinetic energies of 1.3 eV and 1.9 eV, respectively) when the ablation laser wavelength is changed from 355 nm to 266 nm. Increasing the laser fluence per pulse by up to a factor of 10 above threshold results in the appearance of a slower component of the ejected ion flux. The results are interpreted by a photomechanical ejection model in which a photoexcited surface molecule instantaneously becomes larger and recoils away from the surface.

Resonant Laser Ablation of Metals Detected by Atomic Emission in a Microwave Plasma and by Inductively Coupled Plasma Mass Spectrometry

2005 ◽  
Vol 59 (12) ◽  
pp. 1427-1444 ◽  
Author(s):  
Danielle Cleveland ◽  
Peter Stchur ◽  
Xiandeng Hou ◽  
Karl X. Yang ◽  
Jack Zhou ◽  
...  
Keyword(s):  
Thin Films ◽  
Inductively Coupled Plasma ◽  
Wavelength Dependence ◽  
Atomic Emission ◽  
Laser Wavelength ◽  
Inductively Coupled ◽  
Radiation Trapping ◽  
Ablation Laser ◽  
Resonant Laser Ablation ◽  
Resonant Radiation

It has been shown that an increase in sensitivity and selectivity of detection of an analyte can be achieved by tuning the ablation laser wavelength to match that of a resonant gas-phase transition of that analyte. This has been termed resonant laser ablation (RLA). For a pulsed tunable nanosecond laser, the data presented here illustrate the resonant enhancement effect in pure copper and aluminum samples, chromium oxide thin films, and for trace molybdenum in stainless steel samples, and indicate two main characteristics of the RLA phenomenon. The first is that there is an increase in the number of atoms ablated from the surface. The second is that the bandwidth of the wavelength dependence of the ablation is on the order of 1 nm. The effect was found to be virtually identical whether the atoms were detected by use of a microwave-induced plasma with atomic emission detection, by an inductively coupled plasma with mass spectrometric detection, or by observation of the number of laser pulses required to penetrate through thin films. The data indicate that a distinct ablation laser wavelength dependence exists, probably initiated via resonant radiation trapping, and accompanied by collisional broadening. Desorption contributions through radiation trapping are substantiated by changes in crater morphology as a function of wavelength and by the relatively broad linewidth of the ablation laser wavelength scans, compared to gas-phase excitation spectra. Also, other experiments with thin films demonstrate the existence of a distinct laser–material interaction and suggest that a combination of desorption induced by electronic transition (DIET) with resonant radiation trapping could assist in the enhancement of desorption yields. These results were obtained by a detailed inspection of the effect of the wavelength of the ablation laser over a narrow range of energy densities that lie between the threshold of laser-induced desorption of species and the usual analytical ablation regime. Normal ablation employs high-power lasers in an attempt to create a vapor plume without selective vaporization, and with a stoichiometry that accurately represents the stoichiometry of species in the solid sample. RLA, as a method of selective vaporization, appears to provide an opportunity to exploit selective vaporization in new ways.

Imaging nanostructures on ablated kapton polymide

1993 ◽  
Vol 51 ◽  
pp. 872-873
Author(s):  
Daniel L. Callahan ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Polymer Surface ◽  
Grating Period ◽  
Laser Wavelength ◽  
Integrated Devices ◽  
Transmission Electron ◽  
Excimer Laser Irradiation ◽  
Produce Line ◽  
Line Patterns ◽  
Anisotropic Conduction

Excimer laser irradiation has been used to interferometrically ablate submicron line patterns on to Kapton polyimide. Such patterned material may exhibit highly anisotropic conduction as was predicted from previous studies showing enhanced conductivity from uniformly ablated material. We are currently exploiting this phenomenon to create integrated devices using conventional polymers as both dielectrics and conductors. Extensive scanning electron microscopy (SEM) and limited transmission electron microscopy (TEM) have been conducted in order to characterize the morphology of such patterned nanostructures as a function of processing conditions.The ablation technique employed produces an interference pattern on the polymer surface of period equal to half that of a diffraction grating period, independent of the laser wavelength. In these experiments, a 328 nm grating has been used to produce line patterns of 164 nm line-spacings as shown in Figures 1 and 2. A 200 Å Au coating has been used to both prevent charging and, perhaps more importantly, enhance contrast.

Linear and Nonlinear Optical Properties of Natural Dyes Freestanding Films and Application in Optical Limiting

2020 ◽  
pp. 139-143
Keyword(s):  
Absorption Coefficient ◽  
Water Solution ◽  
Optical Limiting ◽  
Refraction Index ◽  
Laser Wavelength ◽  
Solid State Laser ◽  
Natural Dyes ◽  
Linear And Nonlinear ◽  
532 Nm ◽  
Absorbance Spectra

Natural dyes were followed and prepared from a pomegranate, purple carrot, and eggplant peel. The absorbance spectra was measured in the wavelength range 300-800 nm. The linear properties measurements of the prepared natural dye freestanding films were determined include absorption coefficient (α0), extinction coefficient (κ), and linear refraction index (n). The nonlinear refractive index n2 and nonlinear absorption coefficient β2 of the natural dyes in the water solution were measured by the optical z-scan technique under a pumped solid state laser at a laser wavelength of 532 nm. The results indicated that the pomegranate dye can be promising candidates for optical limiting applications with significantly low optical limiting of 3.5 mW.

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