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N Bityurin - One of the best experts on this subject based on the ideXlab platform.
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Studies on Laser Ablation of polymers
Annual Reports on the Progress of Chemistry - Section C, 2005Co-Authors: N BityurinAbstract:This report reviews papers, which were published since the beginning of 2004, and focuses on works related to “pure” Laser Ablation of polymers rather than closely related topics such as Ablation of biological tissues, Laser cleaning of painted artworks, polymer films pulsed Laser deposition, matrix assisted Laser desorption ionization, and Ablation of molecular solids and liquids, although some overlapping with the above subjects, which constitute now separate fields, is inevitable. Papers devoted to both application of Laser Ablation of polymers and study of fundamentals of the process are considered. In concluding remarks, the state of the art in modeling of Laser Ablation of polymers is discussed.
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Models for Laser Ablation of polymers.
Chemical Reviews, 2003Co-Authors: N Bityurin, Boris Luk'yanchuk, Minghui Hong, T. C. ChongAbstract:UV Laser Ablation of polymers was discovered 20 years ago.1,2 This effect has many fascinating applications in lithography, micromechanics, and medicine. For the last 20 years, more than 103 papers describing this phenomenon were published (see, e.g., comprehensive reviews, refs 3-7). Despite the high research activity, the nature of UV Laser Ablation of polymers is still far from being fully understood, e.g., one can find contradictory interpretations of the same results in different papers. Originally, UV Laser Ablation of polymers was believed to be a pure photochemical effect, resulting from the direct bond breaking by UV photons.8-10 Gradually, investigators obtained evidence that Laser heating of materials is significant and a pure thermal nature of Laser Ablation was considered.11-13 Here we use the term “photothermal”7 for the process resulting from Laser heating of material. Polymers are complex materials; therefore, Laser Ablation of polymers is also a complicated phenomenon. In this paper, we will focus on the models of Laser Ablation. In addition, we inevitably have to answer the question of what are the specific features of Laser Ablation of polymers that distinguish them from the Laser Ablation of other materials (metals, semiconductors, inorganic dielectrics, molecular solids). There are several approaches to modeling of polymer Ablation. The authors of this paper represent one of the “schools”; thus, our view of the problem is somewhat subjective. Despite the complex nature of Laser Ablation, we prefer to develop simplified models (e.g., “pure” photochemical or “pure” photothermal), and analyze them in detail to be able to assign specific features, which are experimentally observed for a particular Ablation mechanism. We start with the photochemical model. In fact, the first consideration of Laser Ablation10 employed a very simple but constructive idea that takes into account the specific feature of polymer materials. This idea is that polymers consist of long molecular chains with strong, covalent, bonds inside. At the same time, molecules belonging to different chains interact weakly. Therefore, polymer material becomes simple molecular solid (i.e., easily removed material), if we break the long polymer chains into small pieces by direct photochemical effect (UV photons are considered to have energy pω exceeding the energy of * Corresponding author, e-mail: bit@appl.sci-nnov.ru. † Institute of Applied Physics Russian Academy of Sciences. ‡ Data Storage Institute. 519 Chem. Rev. 2003, 103, 519−552
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VUV Laser Ablation of polymers. Photochemical aspect
Applied Surface Science, 2000Co-Authors: Marie-claude Castex, N Bityurin, C. Olivero, Sergey V. Muraviov, N. G. Bronnikova, D. RiedelAbstract:A photochemical theory of Laser Ablation owing to the direct chain scission process is considered in quite general form taking into account the modification of material. The formulas obtained can be used for estimating mechanisms of VUV Laser Ablation of polymers.
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Pulsed-Laser Ablation
Excimer Lasers, 1994Co-Authors: Dieter Bäuerle, N Bityurin, Boris Luk'yanchuk, Sergei I. AnisimovAbstract:An overview on pulsed-Laser Ablation with special emphasis on the modelling of UV-Laser Ablation is given.
Richard E Russo - One of the best experts on this subject based on the ideXlab platform.
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Laser Ablation in analytical chemistry.
Analytical Chemistry, 2013Co-Authors: Richard E Russo, Xianglei Mao, Jhanis J. Gonzalez, Vassilia Zorba, Jong YooAbstract:In 2002, we wrote an Analytical Chemistry feature article describing the Physics of Laser Ablation in Microchemical Analysis. In line with the theme of the 2002 article, this manuscript discusses c...
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Laser assisted plasma spectrochemistry: Laser Ablation
Journal of Analytical Atomic Spectrometry, 2004Co-Authors: Richard E Russo, X L Mao, Chunyi Liu, Jhanis J. GonzalezAbstract:This paper presents a brief overview of the current research issues in Laser Ablation for chemical analysis, discusses several fundamental studies of Laser Ablation using time-resolved shadowgraph and spectroscopic imaging, and describes recent data using femtosecond Ablation sampling for ICP-MS and LIBS. This manuscript represents a summary of the plenary lecture presented at the 2004 Winter Conference on Plasma Spectrochemistry.
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Femtosecond time-resolved studies of Laser Ablation
High-Power Laser Ablation IV, 2002Co-Authors: Xianglei Mao, Samuel S. Mao, Richard E RussoAbstract:Laser Ablation has proven to be an important technology in an increasing number of applications. The fundamental mechanisms underlying Laser Ablation processes are quite complicated, and include Laser interactions with the target as well as plasma development off the target. While substantial progress has been achieved in understanding Laser Ablation on the nanosecond and picosecond time scales, it remains a considerable challenge to elucidate the underlying mechanisms during femtosecond Laser Ablation. We present experimental observations of plasma development inside silica glass during single femtosecond Laser pulse (100 fs, 800 nm) irradiation. Using a femtosecond time-resolved imaging technique, we measured the evolution of a Laser-induced plasma inside the glass that has an electron number density on the order of 1019 cm-3. Additionally, we observed an air plasma outside the target which forms long before the explosion of a material vapor plume.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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Laser Ablation in analytical chemistry-a review.
Talanta, 2002Co-Authors: Richard E Russo, Xianglei Mao, Haichen Liu, Jhanis J. Gonzalez, Samuel S. MaoAbstract:Laser Ablation is becoming a dominant technology for direct solid sampling in analytical chemistry. Laser Ablation refers to the process in which an intense burst of energy delivered by a short Laser pulse is used to sample (remove a portion of) a material. The advantages of Laser Ablation chemical analysis include direct characterization of solids, no chemical procedures for dissolution, reduced risk of contamination or sample loss, analysis of very small samples not separable for solution analysis, and determination of spatial distributions of elemental composition. This review describes recent research to understand and utilize Laser Ablation for direct solid sampling, with emphasis on sample introduction to an inductively coupled plasma (ICP). Current research related to contemporary experimental systems, calibration and optimization, and fractionation is discussed, with a summary of applications in several areas.
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Femtosecond Laser Ablation ICP-MS
J. Anal. At. Spectrom., 2002Co-Authors: Richard E Russo, X L Mao, Xianglei Mao, Jean Jacques Gonzalez, S S MaoAbstract:Femtosecond Laser Ablation was investigated for direct solid sample chemical analysis. The phonon relaxation time in a solid is of the order of 100 fs, which is the same as the Laser pulse duration. For such excitation, there should be little time for the matrix to experience a "temperature" during the Laser pulse. If the surface explodes before the photon energy is dissipated as heat in the lattice, the Ablation process should produce stoichiometric vapor (elemental fractionation should be negligible). Based on this hypothesis, NIST glasses were ablated using 100 fs Laser pulses at 800 nm, with subsequent elemental analysis using the ICP-MS. Pb and U intensities, and Pb/U ratios in the ICP, were measured during repetitively femtosecond-pulsed Ablation. These data show that fluence (Laser energy/spot area) has a significant influence on the amount of mass ablated and on the degree of fractionation. An optimal fluence was found at which the fractionation index approached unity; negligible fractionation. Infrared femtosecond Laser Ablation produced similar characteristics to UV nanosecond Laser Ablation.
N. G. Semaltianos - One of the best experts on this subject based on the ideXlab platform.
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Nanoparticles by Laser Ablation
Critical Reviews in Solid State and Materials Sciences, 2010Co-Authors: N. G. SemaltianosAbstract:This review concerns nanoparticles collected in the form of nanopowder or a colloidal solution by Laser ablating a solid target that lies in a gaseous or a liquid environment. The paper discusses the advantages of the method as compared with other methods for nanoparticle synthesis, outlines the factors on which the properties of the produced nanoparticles depend, explains the mechanisms and models involved in the generation of nanoparticles by Laser Ablation, clarifies the differences between nanoparticle generation in gaseous and liquid environments, presents some experimental desigins and equipment used by the several groups for nanoparticle generation by Laser Ablation, describes the techniques used for tuning the width of the nanoparticles size distribution, and finally presents a few interesting examples of nanoparticles generated by Laser Ablation. © 2010 Taylor and Francis Group, LLC.
Minghui Hong - One of the best experts on this subject based on the ideXlab platform.
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Femtosecond Laser Ablation of copper
Third International Symposium on Laser Precision Microfabrication, 2003Co-Authors: Yeow Whatt Goh, Minghui Hong, Tow Chong ChongAbstract:In recent years, femtosecond (fs) Laser Ablation has attracted much interest in both basic and applied physics, mainly because of its potential application in micromachining and pulsed Laser deposition. Ultrashort Laser Ablation have the capability to ablate materials precisely with little or no collateral damage, even with materials that are impervious to Laser energy from conventional pulsed Lasers. The extreme intensities and short timescale at which ultrashort pulsed Lasers operate differentiate them from other Lasers such as nanosecond Laser. In this work, we investigate the expansion dynamics of Cu (copper) plasma generated by ultrashort Laser Ablation of pure copper targets by optically examining the plasma plume. Time-integrated optical emission spectroscopy measurements by using intensified charged couple detector array (ICCD) imaging were used to detect the species present in the plasma and to study the Laser-generated plasma formation and evolution. Temporal emission profiles are measured. Our interest in the dynamics of Laser-generated copper plasma arises from the fact that copper has been considered as a substitute for Aluminum (Al) interconnects/metallization in ULSI devices (for future technology). It is important to know the composition and behavior of copper plasma species for the understanding of the mechanisms involved and optimizing the micro-machining processes and deposition conditions.
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Models for Laser Ablation of polymers.
Chemical Reviews, 2003Co-Authors: N Bityurin, Boris Luk'yanchuk, Minghui Hong, T. C. ChongAbstract:UV Laser Ablation of polymers was discovered 20 years ago.1,2 This effect has many fascinating applications in lithography, micromechanics, and medicine. For the last 20 years, more than 103 papers describing this phenomenon were published (see, e.g., comprehensive reviews, refs 3-7). Despite the high research activity, the nature of UV Laser Ablation of polymers is still far from being fully understood, e.g., one can find contradictory interpretations of the same results in different papers. Originally, UV Laser Ablation of polymers was believed to be a pure photochemical effect, resulting from the direct bond breaking by UV photons.8-10 Gradually, investigators obtained evidence that Laser heating of materials is significant and a pure thermal nature of Laser Ablation was considered.11-13 Here we use the term “photothermal”7 for the process resulting from Laser heating of material. Polymers are complex materials; therefore, Laser Ablation of polymers is also a complicated phenomenon. In this paper, we will focus on the models of Laser Ablation. In addition, we inevitably have to answer the question of what are the specific features of Laser Ablation of polymers that distinguish them from the Laser Ablation of other materials (metals, semiconductors, inorganic dielectrics, molecular solids). There are several approaches to modeling of polymer Ablation. The authors of this paper represent one of the “schools”; thus, our view of the problem is somewhat subjective. Despite the complex nature of Laser Ablation, we prefer to develop simplified models (e.g., “pure” photochemical or “pure” photothermal), and analyze them in detail to be able to assign specific features, which are experimentally observed for a particular Ablation mechanism. We start with the photochemical model. In fact, the first consideration of Laser Ablation10 employed a very simple but constructive idea that takes into account the specific feature of polymer materials. This idea is that polymers consist of long molecular chains with strong, covalent, bonds inside. At the same time, molecules belonging to different chains interact weakly. Therefore, polymer material becomes simple molecular solid (i.e., easily removed material), if we break the long polymer chains into small pieces by direct photochemical effect (UV photons are considered to have energy pω exceeding the energy of * Corresponding author, e-mail: bit@appl.sci-nnov.ru. † Institute of Applied Physics Russian Academy of Sciences. ‡ Data Storage Institute. 519 Chem. Rev. 2003, 103, 519−552
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Steam-assisted Laser Ablation and its signal diagnostics
Applied Surface Science, 2002Co-Authors: Minghui Hong, M. L. Koh, S. Zhu, Tow Chong ChongAbstract:Abstract Steam-assisted Laser Ablation of solid substrates is investigated. With the aid of a steam layer in dozens of microns, Laser Ablation with 1.5 times higher Ablation rate and wider ablated crater than that in the ambient air can be achieved. Surface morphology improves greatly with three times lower protrusions along the crater edge. It implies that the Laser processing speed and Ablation quality can be enhanced a lot with steam assistance. Mechanisms of the Ablation enhancement are studied based on plasma and shock wave confinement, heat dissipation and Laser–plasma interaction during the Laser Ablation. Diagnostics of audible acoustic waves and plasma signals during the Laser Ablation in air and with steam assistance are carried out for a better understanding of the Laser processing.
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Diagnostics and real-time monitoring of pulsed Laser Ablation
Second International Symposium on Laser Precision Microfabrication, 2002Co-Authors: Minghui Hong, Tow Chong ChongAbstract:Signal generation, diagnostics and real-time monitoring during pulsed Laser Ablation of solid materials (silicon, metal and IC molding component) are investigated. It is found that there is rich signal emission in the Laser Ablation. Wide band microphone, ultrafast phototube and tiny metal probe are applied to detect acoustic, optical and electric signals generated during the Laser Ablation. Optical emission spectrum analyzer and high-speed ICCD photography are used to study Laser-Ablation-induced plasma dynamics. Signal variation with Laser processing conditions during the Laser Ablation is analyzed. Formation of the signals is also discussed and modeled. Based on the signal diagnostics and analyses, relations between signal characteristic parameters and the Laser processing conditions can be established for different applications of Laser Ablation in industry.
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Laser Ablation of Si in water and ambient air
Second International Symposium on Laser Precision Microfabrication, 2002Co-Authors: Sha Zhu, Minghui Hong, M. L. KohAbstract:Laser Ablation of Si in ambient air and under water is investigated. It is found that the Laser Ablation rate of Si varies with the thickness of the water layer above the Si substrates. The Laser Ablation rate is the most highly enhanced with the water layer of 1.1 mm. It is assumed that the plasma generated in water confinement regime (WCR) with an optimal water layer thickness induces the strongest pressure. This high-pressure, high-temperature plasma results in the high Ablation rate. It is found that the first peak-to-peak amplitude of the acoustic wave is the strongest when the water layer thickness is 1.1 mm above the substrate. By proper calibration, acoustic wave detection can be used as a real-time monitoring of the Laser Ablation.
Xianglei Mao - One of the best experts on this subject based on the ideXlab platform.
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Laser Ablation in analytical chemistry.
Analytical Chemistry, 2013Co-Authors: Richard E Russo, Xianglei Mao, Jhanis J. Gonzalez, Vassilia Zorba, Jong YooAbstract:In 2002, we wrote an Analytical Chemistry feature article describing the Physics of Laser Ablation in Microchemical Analysis. In line with the theme of the 2002 article, this manuscript discusses c...
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Femtosecond time-resolved studies of Laser Ablation
High-Power Laser Ablation IV, 2002Co-Authors: Xianglei Mao, Samuel S. Mao, Richard E RussoAbstract:Laser Ablation has proven to be an important technology in an increasing number of applications. The fundamental mechanisms underlying Laser Ablation processes are quite complicated, and include Laser interactions with the target as well as plasma development off the target. While substantial progress has been achieved in understanding Laser Ablation on the nanosecond and picosecond time scales, it remains a considerable challenge to elucidate the underlying mechanisms during femtosecond Laser Ablation. We present experimental observations of plasma development inside silica glass during single femtosecond Laser pulse (100 fs, 800 nm) irradiation. Using a femtosecond time-resolved imaging technique, we measured the evolution of a Laser-induced plasma inside the glass that has an electron number density on the order of 1019 cm-3. Additionally, we observed an air plasma outside the target which forms long before the explosion of a material vapor plume.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
-
Laser Ablation in analytical chemistry-a review.
Talanta, 2002Co-Authors: Richard E Russo, Xianglei Mao, Haichen Liu, Jhanis J. Gonzalez, Samuel S. MaoAbstract:Laser Ablation is becoming a dominant technology for direct solid sampling in analytical chemistry. Laser Ablation refers to the process in which an intense burst of energy delivered by a short Laser pulse is used to sample (remove a portion of) a material. The advantages of Laser Ablation chemical analysis include direct characterization of solids, no chemical procedures for dissolution, reduced risk of contamination or sample loss, analysis of very small samples not separable for solution analysis, and determination of spatial distributions of elemental composition. This review describes recent research to understand and utilize Laser Ablation for direct solid sampling, with emphasis on sample introduction to an inductively coupled plasma (ICP). Current research related to contemporary experimental systems, calibration and optimization, and fractionation is discussed, with a summary of applications in several areas.
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Femtosecond Laser Ablation ICP-MS
J. Anal. At. Spectrom., 2002Co-Authors: Richard E Russo, X L Mao, Xianglei Mao, Jean Jacques Gonzalez, S S MaoAbstract:Femtosecond Laser Ablation was investigated for direct solid sample chemical analysis. The phonon relaxation time in a solid is of the order of 100 fs, which is the same as the Laser pulse duration. For such excitation, there should be little time for the matrix to experience a "temperature" during the Laser pulse. If the surface explodes before the photon energy is dissipated as heat in the lattice, the Ablation process should produce stoichiometric vapor (elemental fractionation should be negligible). Based on this hypothesis, NIST glasses were ablated using 100 fs Laser pulses at 800 nm, with subsequent elemental analysis using the ICP-MS. Pb and U intensities, and Pb/U ratios in the ICP, were measured during repetitively femtosecond-pulsed Ablation. These data show that fluence (Laser energy/spot area) has a significant influence on the amount of mass ablated and on the degree of fractionation. An optimal fluence was found at which the fractionation index approached unity; negligible fractionation. Infrared femtosecond Laser Ablation produced similar characteristics to UV nanosecond Laser Ablation.
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Laser Ablation sampling
Trends in Analytical Chemistry, 1998Co-Authors: Re Russo, Xianglei Mao, Oleg V. BorisovAbstract:Abstract Laser Ablation sampling provides significant benefits and capabilities for chemical analysis. It represents one of the most promising technologies for direct solid sample introduction. Despite the advantages, there are a number of issues that should be addressed to better understand and utilize this technology. Laser Ablation itself is a complex process and is poorly understood, fundamentally. In this paper, we describe the current achievements and limitations in order to better understand and utilize Laser Ablation sampling for chemical analysis. Several current issues related to Laser Ablation sampling are discussed, including calibration and optimization, fractionation, sensitivity enhancements, mass loading, and particle transport.
