Influence of ambient gas on the temperature and density of laser produced carbon plasma
TL;DR: In this article, the effect of ambient gas on the dynamics of the plasma generated by laser ablation of a carbon target using 1.06 μm radiation from a Q-switched Nd:YAG laser has been investigated using a spectroscopic technique.
Abstract: The effect of ambient gas on the dynamics of the plasma generated by laser ablation of a carbon target using 1.06 μm radiation from a Q-switched Nd:YAG laser has been investigated using a spectroscopic technique. The emission characteristics of the carbon plasma produced in argon, helium and air atmospheres are found to depend strongly on the nature and pressure of the surrounding gas. It has been observed that hotter and denser plasmas are formed in an argon atmosphere rather than in helium or air as an ambient.
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TL;DR: In this paper, the effect of ambient gas on the expansion dynamics of the plume generated by laser ablation of an aluminum target has been investigated using frequency doubled radiation from a Q-switched Nd:YAG laser.
Abstract: The effect of ambient gas on the expansion dynamics of the plasma generated by laser ablation of an aluminum target has been investigated using frequency doubled radiation from a Q-switched Nd:YAG laser. The diagnostic tools include fast photography of overall visible plume emission using a 2 ns gated intensified charged coupled device and space and time resolved emission spectroscopy using a 50 cm monochromator/spectrograph and photomultiplier tube. The expansion behavior of the plasma was studied with ambient air pressure ranging from 10−6 to 100 Torr. Free expansion, plume splitting and sharpening, hydrodynamic instability, and stagnation of the plume were observed at different pressure levels. Space and time resolved emission spectroscopic studies showed a twin peak distribution for Al and Al+ species at farther distances illustrating plume splitting at pressures higher than 100 mTorr. Combining imaging together with time resolved emission diagnostics, a triple structure of the plume was observed. The expansion of the plume front was compared with various expansion models and found to be generally in good agreement.
475 citations
TL;DR: In this article, the influence of ambient pressure on the spectral emission features and expansion dynamics of a plasma plume generated on a metal target has been investigated by irradiating Cu targets using 6'ns, 1064'nm pulses from a Q-switched Nd:YAG laser.
Abstract: The influence of ambient pressure on the spectral emission features and expansion dynamics of a plasma plume generated on a metal target has been investigated. The plasma plumes were generated by irradiating Cu targets using 6 ns, 1064 nm pulses from a Q-switched Nd:YAG laser. The emission and expansion dynamics of the plasma plumes were studied by varying air ambient pressure levels ranging from vacuum to atmospheric pressure. The ambient pressure levels were found to affect both the line intensities and broadening along with the signal to background and signal to noise ratios and the optimum pressure conditions for analytical applications were evaluated. The characteristic plume parameters were estimated using emission spectroscopy means and noticed that the excitation temperature peaked ∼300 Torr, while the electron density showed a maximum ∼100 Torr. Fast-gated images showed a complex interaction between the plume and background air leading to changes in the plume geometry with pressure as well as time. Surface morphology of irradiated surface showed that the pressure of the ambient gas affects the laser-target coupling significantly.
160 citations
TL;DR: In this paper, an initial temperature of 3.2 eV and density of 7.7×1017 cm−3 were measured using Boltzmann diagram method using singly ionized Sn lines, while density measurements were made using the Stark broadening method.
Abstract: Optical emission spectroscopic studies have been carried out on a tin plasma generated using 1064-nm, 8-ns pulses from a Nd:yttrium aluminum garnet laser. Temperature and density were estimated from the analysis of spectral data. The temperature measurements have been performed by Boltzmann diagram method using singly ionized Sn lines, while density measurements were made using the Stark broadening method. An initial temperature of 3.2 eV and density of 7.7×1017cm−3 were measured. Temporal and spatial behaviors of electron temperature and density in the laser-generated tin plasma have been analyzed. Time evolutions of density and temperature are found to decay adiabatically at early times. The spatial variation of density shows approximately 1∕z dependence. The time-integrated temperature exhibits an appreciable rise at distances greater than 7 mm. This may be caused by the deviation from local thermodynamic equilibrium at larger distances from the target surface.
156 citations
TL;DR: In this paper, the authors explore the evolution of laser-induced plasma (LIP) properties, especially plasma temperature, with regard to variations of experiment conditions in both theoretical study and routine applications.
133 citations
TL;DR: In this article, a review of the existing knowledge/technological gaps identified from the current literature and suggestions for the future work is presented, followed by the physics behind solid sampling of laser ablation plumes, optical methods for isotope measurements, the suitable physical conditions of laser-produced plasma plumes for isotopic analysis, and the current status.
Abstract: Rapid, in-field, and non-contact isotopic analysis of solid materials is extremely important to a large number of applications, such as nuclear nonproliferation monitoring and forensics, geochemistry, archaeology, and biochemistry. Presently, isotopic measurements for these and many other fields are performed in laboratory settings. Rapid, in-field, and non-contact isotopic analysis of solid material is possible with optical spectroscopy tools when combined with laser ablation. Laser ablation generates a transient vapor of any solid material when a powerful laser interacts with a sample of interest. Analysis of atoms, ions, and molecules in a laser-produced plasma using optical spectroscopy tools can provide isotopic information with the advantages of real-time analysis, standoff capability, and no sample preparation requirement. Both emission and absorption spectroscopy methods can be used for isotopic analysis of solid materials. However, applying optical spectroscopy to the measurement of isotope ratios from solid materials presents numerous challenges. Isotope shifts arise primarily due to variation in nuclear charge distribution caused by different numbers of neutrons, but the small proportional nuclear mass differences between nuclei of various isotopes lead to correspondingly small differences in optical transition wavelengths. Along with this, various line broadening mechanisms in laser-produced plasmas and instrumental broadening generated by the detection system are technical challenges frequently encountered with emission-based optical diagnostics. These challenges can be overcome by measuring the isotope shifts associated with the vibronic emission bands from molecules or by using the techniques of laser-based absorption/fluorescence spectroscopy to marginalize the effect of instrumental broadening. Absorption and fluorescence spectroscopy probe the ground state atoms existing in the plasma when it is cooler, which inherently provides narrower lineshapes, as opposed to emission spectroscopy which requires higher plasma temperatures to be able to detect thermally excited emission. Improvements in laser and detection systems and spectroscopic techniques have allowed for isotopic measurements to be carried out at standoff distances under ambient atmospheric conditions, which have expanded the applicability of optical spectroscopy-based isotopic measurements to a variety of scientific fields. These technological advances offer an in-situ measurement capability that was previously not available. This review will focus on isotope detection through emission, absorption, and fluorescence spectroscopy of atoms and molecules in a laser-produced plasma formed from a solid sample. A description of the physics behind isotope shifts in atoms and molecules is presented, followed by the physics behind solid sampling of laser ablation plumes, optical methods for isotope measurements, the suitable physical conditions of laser-produced plasma plumes for isotopic analysis, and the current status. Finally, concluding remarks will be made on the existing knowledge/technological gaps identified from the current literature and suggestions for the future work.
133 citations
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01 Jan 1973TL;DR: CRC handbook of chemistry and physics, CRC Handbook of Chemistry and Physics, CRC handbook as discussed by the authors, CRC Handbook for Chemistry and Physiology, CRC Handbook for Physics,
Abstract: CRC handbook of chemistry and physics , CRC handbook of chemistry and physics , کتابخانه مرکزی دانشگاه علوم پزشکی تهران
52,268 citations
01 Jan 1994
TL;DR: Pulsed laser deposition of high-temperature superconducting thin films for active and passive device applications is discussed in this article, with a focus on the commercial scale-up of Pulsed Laser Deposition.
Abstract: Partial table of contents: History and Fundamentals of Pulsed Laser Deposition (J. Cheung). Diagnostics and Characteristics of Laser--Produced Plasmas (D. Geohegan). Particulates Generated by Pulsed Laser Ablation (L.--C. Chen). Angular Distribution of Ablated Material (K. Saenger). Film Nucleation and Film Growth in Pulsed Laser Deposition of Ceramics (J. Horwitz & J. Sprague). Processes Characteristics and Film Properties in Pulsed Laser Plasma Deposition (S. Metev). Commercial Scale--Up of Pulsed Laser Deposition (J. Greer). Pulsed Laser Deposition: Future Trends (T. Venkatesan). Comparison of Vacuum Deposition Techniques (G. Hubler). Pulsed Laser Deposition of High--Temperature Superconducting Thin Films for Active and Passive Device Applications (R. Muenchausen & X. Wu). Pulsed Laser Deposition of Metals (J. Kools). Appendix. References. Index.
3,228 citations
10 Sep 2020
TL;DR: In this article, the authors discuss optical science, engineering, and technology topics covered include the laser and its many commercial and industrial applications, the new optical materials, gradient index optics, electro-and acousto-optics, fiber optics and communications, optical computing and pattern recognition, optical data reading, recording and storage, biomedical instrumentation, industrial robotics, integrated optics, infrared and ultraviolet systems
Abstract: This book discusses optical science, engineering, and technology Topics covered include the laser and its many commercial and industrial applications, the new optical materials, gradient index optics, electro- and acousto-optics, fiber optics and communications, optical computing and pattern recognition, optical data reading, recording and storage, biomedical instrumentation, industrial robotics, integrated optics, infrared and ultraviolet systems
643 citations
TL;DR: Cluster-assembled nanocrystalline and composite films offer opportunities to control and produce new combinations of properties with PLD, and artificially layered materials and metastable phases have been created and their properties varied by control of the layer thicknesses.
Abstract: Pulsed laser deposition (PLD) is a conceptually and experimentally simple yet highly versatile tool for thin-film and multilayer research. Its advantages for the film growth of oxides and other chemically complex materials include stoichiometric transfer, growth from an energetic beam, reactive deposition, and inherent simplicity for the growth of multilayered structures. With the use of PLD, artificially layered materials and metastable phases have been created and their properties varied by control of the layer thicknesses. In situ monitoring techniques have provided information about the role of energetic species in the formation of ultrahard phases and in the doping of semiconductors. Cluster-assembled nanocrystalline and composite films offer opportunities to control and produce new combinations of properties with PLD.
586 citations
TL;DR: In this article, a central mystery of the fullerene story is solved: how carbon can be made spontaneously in high yield simply by condensing carbon vapor in a special way.
Abstract: The account deals with a central mystery of the fullerene story: How are they made How can the fullerenes in general, and C[sub 60] in particular, possibly, be made spontaneously in high yield simply by condensing carbon vapor in a special way The mystery of how this happens in the case of carbon is still by no means fully resolved. Theories of this process are discussed.
477 citations