Laserinduced breakdown spectroscopy (LIBS) is a rapidly growing elemental analyses technique that uses a short laser pulse to create a microplasma, so called laserinduced plasma (LIP), on the sample surface. The principle of LIBS is quite simple however although the physical processes involved in the lasermatter interaction are quite complex and still not completely explained. In LIBS, the laser pulses are focused onto the surface of sample target (solid, liquid as well as gas samples) so as to generate a high temperature microplasma (LIP) that vaporizes a small amount of samples material. The light emission from LIP, which contains the excited atomic and ionic species, is then collected and spectrally analyzed to determine the elemental constituents of target material. LIBS analysis can also provide the quantitative information provided the assumptions of local thermal equilibrium (LTE) and optically thin
Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Laser Induced Breakdown Spectroscopy (LIBS) Concepts, Instrumentation, Data Analysis and Applications Volume Edited by Vivek K Singh University of Lucknow Lucknow, India Durgesh K Tripathi Amity University Uttar Pradesh Noida, India Yoshihiro Deguchi Tokushima University Tokushima, Japan Zhenzhen Wang Xi’an Jiaotong University Xi’an, China Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Laser Induced Breakdown Spectroscopy (LIBS) All rights reserved No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions The right of Vivek K Singh, Durgesh K Tripathi, Yoshihiro Deguchi and Zhenzhen Wang to be identified as the authors of the editorial material in this work has been asserted in accordance with law Registered Offices John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com Wiley also publishes its books in a variety of electronic formats and by print-on-demand Some content that appears in standard print versions of this book may not be available in other formats Trademarks: Wiley and the Wiley logo are trademarks or registered trademarks of John Wiley & Sons, Inc and/or its affiliates in the United States and other countries and may not be used without written permission All other trademarks are the property of their respective owners John Wiley & Sons, Inc is not associated with any product or vendor mentioned in this book Limit of Liability/Disclaimer of Warranty In view of ongoing research, equipment modifications, changes in governmental regulations, and the constant flow of information relating to the use of experimental reagents, equipment, and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each chemical, piece of equipment, reagent, or device for, among other things, any changes in the instructions or indication of usage and for added warnings and precautions While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchantability or fitness for a particular purpose No warranty may be created or extended by sales representatives, written sales materials or promotional statements for this work The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make This work is sold with the understanding that the publisher is not engaged in rendering professional services The advice and strategies contained herein may not be suitable for your situation You should consult with a specialist where appropriate Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages Library of Congress Cataloging-in-Publication Data Applied for [Hardback ISBN: 9781119758402] Cover Design: Wiley Cover Images: © Georgy Shafeev/Shutterstock; Roxana Bashyrova/Shutterstock Set in 9.5/12.5pt STIXTwoText by Straive, Chennai, India Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License This edition first published 2023 © 2023 John Wiley & Sons Ltd Vivek K Singh Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License In the loving memories of my Grandparents (Late) Shri Thakur Prasad Singh, (Late) Mrs Shyama Devi, (Late) Shri Lallan Prasad Singh and (Late) Smt Sona Devi, (Late) Shri Ranjeet Singh; and my Elder Parents (Late) Shri Rajeshwar Prasad Singh (Kallan Singh) and (Late) Smt Malati Singh Contents Volume Preface xix Part I 1.1 1.2 1.3 1.4 1.5 1.6 1.7 2.1 2.2 2.3 2.4 2.5 2.6 3.1 Fundamental Aspects of LIBS and Laser-Induced Plasma Nanosecond and Femtosecond Laser-Induced Breakdown Spectroscopy: Fundamentals and Applications K M Muhammed Shameem, Swetapuspa Soumyashree, P Madhusudhan, Vinitha Nimma, Rituparna Das, Pranav Bhardwaj, Prashant Kumar and Rajesh K Kushawaha Introduction LIBS: ns-LIBS and fs-LIBS Plasma-Plume Dynamics 10 Filamentation 14 Signal-Enhancing Strategies in LIBS 17 Applications 20 Summary 21 References 22 Elementary Processes and Emission Spectra in Laser-Induced Plasma 33 V Gardette, Z Salajkova, M Dell’Aglio and A De Giacomo Introduction 33 Laser-Ablation Mechanism 33 Plasma Characteristics and Elementary Processes 35 Plasma in Thermodynamic Equilibrium 37 Plasma Emission Features 39 Conclusion 41 References 41 Diagnostics of Laser-Induced Plasma 45 Charles Ghany, Kyung-Min Lee, Herve K Sanghapi and Vivek K Singh Introduction 45 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License vii Contents 3.2 3.2.1 3.2.2 3.2.3 3.2.3.1 3.2.3.2 3.2.4 3.2.4.1 3.2.4.2 3.3 3.3.1 3.3.2 3.3.3 3.3.4 3.3.5 3.3.6 3.4 3.5 3.6 3.7 3.8 4.1 4.2 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.2.6 4.3 4.4 4.4.1 4.4.2 4.4.3 4.4.4 4.5 LIBS Plasmas and Its Characteristics 46 Laser-Induced Plasma 46 Plasma Temperature Measurements 46 Electron Density Measurements 47 Nonlinear Stark Broadening 47 Linear Stark Broadening 48 Additional Comments on the Characteristics of LIBS Plasmas 48 Matrix Effect 48 McWhirter Criterion 49 Factors Affecting the LIBS Plasma 49 Laser Characteristics 49 Wavelength and Pulse Duration of Laser 50 Properties of Target Material 50 Time Window of Observation 50 Geometric Setup 50 Ambient Gas 50 Methods of Enhancing LIBS Sensitivity 51 LTE Plasmas and Non-LTE Plasmas 52 Laser–Plasma Expansion in Gas and Liquids: Modeling and Validation 54 Chemistry in Laser Plasmas (Biological, Medical, and Isotopic Applications) 57 Conclusion 58 References 59 Double and Multiple Pulse LIBS Techniques 65 Francesco Poggialini, Asia Botto, Beatrice Campanella, Simona Raneri, Vincenzo Palleschi and Stefano Legnaioli Introduction 65 Double-Pulse LIBS: Geometries and Configurations 67 Collinear DP-LIBS 67 Orthogonal DP-LIBS 68 Parallel DP-LIBS 70 Variable Pulse Duration in DP-LIBS 72 Variable Pulse Wavelength in DP-LIBS 73 Multiple Pulse LIBS 75 Signal Enhancement in DP-LIBS: Principles and Theory 77 Applications of DP-LIBS 80 DP-LIBS of Archaeological Artifacts 80 DP-LIBS for the Stand-Off Detection of Explosives 81 DP-LIBS for the Analysis of Biological Materials 81 DP-μ-LIBS Mapping 83 Conclusions 83 References 84 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License viii 5.1 5.2 5.2.1 5.2.2 5.2.3 5.2.4 5.2.5 5.3 5.3.1 5.3.2 5.3.3 5.3.4 5.3.4.1 5.3.4.2 5.3.4.3 5.4 5.4.1 5.4.2 5.4.2.1 5.4.2.2 5.4.3 5.4.3.1 5.4.3.2 5.4.3.3 5.4.4 5.4.4.1 5.4.4.2 5.4.4.3 5.5 Calibration-Free Laser-Induced Breakdown Spectroscopy 89 Jörg Hermann Introduction 89 Validity Conditions of the Physical Model 90 Congruent Mass Transfer from the Solid Sample Toward Plasma 90 Local Thermodynamic Equilibrium 92 Spatial Distribution of Plasma 93 Self-Absorption 94 Chemical Reactions 95 Methods of Calibration-Free Measurements 98 The Mathematical Problem of a Multielemental Equilibrium Plasma 98 First CF-LIBS Method for Ideal Plasma 99 Amended Methods 100 Methods Based on Spectra Simulation 101 Calculation of Spectral Radiance 101 Implementation in Measurement Algorithm 104 Illustration for Alloy 105 Critical Review of Analytical Performance 107 Model Validity 107 Error Evaluation 107 Minor and Trace Element Quantification 107 Error due to Self-Absorption 109 Recommendations 111 Apparatus Requirements 111 Setting the Experimental Conditions 111 Selection of Spectral Lines 113 Expected Improvements 114 Evolution of the Spectroscopic Database 114 Advanced Instrumentation 114 Improved Knowledge of Laser-Induced Plasma 114 Conclusion 115 References 115 Part II 6.1 6.2 6.3 6.4 Molecular LIBS and Instrumentation Developments 123 Molecular Species Formation in Laser-Produced Plasma 125 K M Muhammed Shameem, Swetapuspa Soumyashree, P Madhusudhan, Vinitha Nimma, Rituparna Das, Pranav Bhardwaj and Rajesh K Kushawaha Introduction 125 Atmospheric Contribution in LIBS Spectra 127 CN and C2 Molecular Formation in LIP 127 Summary 134 References 134 ix Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Contents Contents 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 7.10 7.11 7.12 8.1 8.2 8.2.1 8.2.2 8.2.3 8.2.4 8.2.5 8.2.6 8.3 8.3.1 8.3.2 8.4 9.1 9.2 9.3 9.4 9.5 Recent Developments in Standoff Laser-Induced Breakdown Spectroscopy 137 Linga Murthy Narlagiri and Venugopal Rao Soma Introduction 137 Laser Systems Used 137 Instrumentation in Standoff LIBS 138 Gated and Non-Gated CCDs/Spectrometers 139 Experimental Setup 139 Reviews on Standoff LIBS 140 Studies in Standoff LIBS 140 Variants in Standoff LIBS 146 Machine-Learning for Data Analysis in Standoff Mode 149 Advancements in Standoff LIBS Methods 150 Ongoing Study at ACRHEM, University of Hyderabad 153 Conclusions and Outlook 158 Acknowledgments 159 References 159 Nanoparticle-Enhanced Laser-Induced Breakdown Spectroscopy 165 Zita Salajková, Marcella Dell’Aglio, Vincent Gardette and Alessandro De Giacomo Introduction 165 Fundamentals 166 Plasmon Excitation in NPs During NELIBS 166 Broadening of the Plasmon Frequency due to Plasmon Coupling 167 Local Field Enhancement 168 Influence of Sample Properties on Laser Ablation Mechanism During NELIBS 170 Nanoparticles Under a Strong Electromagnetic Field and Consequently in the Plasma Phase 171 Origin of Plasma Emission Enhancement 173 Applications 174 Sample Preparation and Setup 174 Application in the Field of Analytical Chemistry 175 Conclusion 179 References 179 Nanoparticle-Enhanced Laser-Induced Breakdown Spectroscopy for Sensing Applications 183 Linga Murthy Narlagiri and Venugopal Rao Soma Introduction 183 Previous Reviews 183 Experimental Setup 184 Enhancement Via Different Conditions 185 Perspectives on the Mechanism(s) of Enhancement 191 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License x 9.6 9.7 9.8 9.9 9.10 Variations in NE-LIBS 199 Beyond NE-LIBS 200 Further Application of Nanoparticles in LIBS 202 Ongoing Study in the Lab 203 Conclusions 204 References 205 Part III 10 10.1 10.2 10.3 10.4 10.4.1 10.4.2 10.4.3 10.5 11 11.1 11.2 11.3 11.3.1 11.4 11.4.1 11.5 12 12.1 12.2 12.2.1 12.3 12.3.1 12.3.2 12.3.3 12.3.4 12.4 Data Analysis and Chemometrics in LIBS 211 Full-Spectrum Multivariate Analysis of LIBS Data Catherine E McManus and Nancy J McMillan Introduction 213 Full-Spectrum Multivariate Analysis 215 Analysis of Geologic Samples 216 Identification of Pharmaceuticals 218 Methods 218 Acetaminophen 218 Aspirin 222 Conclusions 224 References 224 213 Chemometrics for Data Analysis 229 Manoj Kumar Gundawar and Rajendhar Junjuri Introduction 229 Data 230 Machine Learning 231 Principal Component Analysis 234 Classification of the Data 236 Artificial Neural Network 236 Conclusion 237 References 238 Chemometric Processing of LIBS Data 241 J El Haddad, A Harhira, E Képeš, J Vrábel, J Kaiser and P Poˇrízka Introduction 241 Exploratory Analysis Methods for Visualization 243 Principal Component Analysis 244 Quantitative Analysis Methods 249 Main Steps of Multivariate Calibration Before and After LIBS Measurements 250 Multiple Linear Regression 251 Principal Component Regression 251 Partial Least Squares 252 Classification 254 xi Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Contents 25 Huang, J., Dong, M., Lu, S et al (2019) A hybrid model combining wavelet transform and recursive feature elimination for running state evaluation of heat-resistant steel using laser-induced breakdown spectroscopy Analyst 144 (12): 3736–3745 26 Cai, J., Dong, M., Zhang, Y et al (2021) Estimating the aging grade of heat-resistant steel by using portable laser-induced breakdown spectroscopy Atomic Spectroscopy 42 (2): 43–50 27 GBT 6394-2002 (2022) Metal-methods for estimating the average grain size China: General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China (in Chinese) 28 GBT 2039-1997 (1997) Metallic materials – Creep and stress-rupture test in tension China: The state bureau of quality and technical supervision (in Chinese) 29 Li, J., Lu, J., Li, J et al (2011) Laser-induced plasma spectra of heating surface materials with different hardness Chinese Journal of Lasers 38 (8): 233–238 (in Chinese) 30 Yao, S., Dong, M., Lu, J et al (2013) Correlation between grade of pearlite spheroidization and laser induced spectra Laser Physics 23 (12): 125702 31 Abdel-Salam, Z., Nanjing, Z., Anglos, D et al (2009) Effect of experimental conditions on surface hardness measurements of calcified tissues via LIBS Applied Physics B 94 (1): 141–147 32 Li, J., Lu, J., Dai, Y et al (2015) Correlation between aging grade of T91 steel and spectral characteristics of the laser-induced plasma Applied Surface Science 346: 302–310 33 Yu, Z., Liu, J., Wang, Z et al (2007) Analysis on ripening of carbides during service of T91 steel Zhuzao Jishu (Foundry Technology) 28 (5): 635–638 (in Chinese) 34 Wang, X., Zhang, X., Zhan, L et al (2012) Microstructure degradation behavior and its influence on high temperature stress rupture limit of T 91 steel Zhongguo Dianji Gongcheng Xuebao(Proceedings of the Chinese Society of Electrical Engineering) 32 (29): 137–142 (in Chinese) 35 Zhang, D., Liu, Z., Mao, L et al (2008) Microstructure and properties of T91 steel after accelerated aging Heat Treatment of Metals 33 (6): 88–90 (in Chinese) 36 Abdel-Salam, Z., Galmed, A., Tognoni, E et al (2007) Estimation of calcified tissues hardness via calcium and magnesium ionic to atomic line intensity ratio in laser induced breakdown spectra Spectrochimica Acta Part B: Atomic Spectroscopy 62 (12): 1343–1347 37 Jeong, S., Greif, R., and Russo, R (1999) Shock wave and material vapour plume propagation during excimer laser ablation of aluminium samples Journal of Physics D: Applied Physics 32 (19): 2578 38 Yao, S., Lu, J., Chen, K et al (2011) Study of laser-induced breakdown spectroscopy to discriminate pearlitic/ferritic from martensitic phases [J] Applied Surface Science 257 (7): 3103–3110 39 Zhou, Y., Wu, B., Tao, S et al (2011) Physical mechanism of silicon ablation with long nanosecond laser pulses at 1064 nm through time-resolved observation Applied Surface Science 257 (7): 2886–2890 40 Zhou, X., Imasaki, K., Furukawa, H et al (2001) A study of the surface products on zinc-coated steel during laser ablation cleaning Surface and Coatings Technology 137 (2–3): 170–174 935 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License References 45 Application of LIBS for the Failure Characteristics Prediction of Heat-Resistant Steel 41 Lasemi, N., Pacher, U., Zhigilei, L.V et al (2018) Pulsed laser ablation and incubation of nickel, iron and tungsten in liquids and air Applied Surface Science 433 (3): 772–779 42 Martin, M.Z., Labbé, N., Rials, T.G et al (2005) Analysis of preservative-treated wood by multivariate analysis of laser-induced breakdown spectroscopy spectra Spectrochimica Acta Part B: Atomic Spectroscopy 60 (7–8): 1179–1185 43 Munson, C., De Lucia, F., Piehler, T et al (2005) Investigation of statistics strategies for improving the discriminating power of laser-induced breakdown spectroscopy for chemical and biological warfare agent simulants Spectrochimica Acta Part B: Atomic Spectroscopy 60 (7–8): 1217–1224 44 Sirven, J., Salle, B., Mauchien, P et al (2007) Feasibility study of rock identification at the surface of Mars by remote laser-induced breakdown spectroscopy and three chemometric methods Journal of Analytical Atomic Spectrometry 22 (12): 1471–1480 45 Judge, E., Heck, G., Cerkez, E.B et al (2009) Discrimination of composite graphite samples using remote filament-induced breakdown spectroscopy Analytical Chemistry 81 (7): 2658–2663 46 Hilbk-Kortenbruck, F., Noll, R., Wintjens, P et al (2001) Analysis of heavy metals in soils using laser-induced breakdown spectrometry combined with laser-induced fluorescence Spectrochimica Acta Part B: Atomic Spectroscopy 56 (6): 933–945 47 Lu, S., Dong, M., Huang, J et al (2018) Estimation of the aging grade of T91 steel by laser-induced breakdown spectroscopy coupled with support vector machines Spectrochimica Acta Part B: Atomic Spectroscopy 140: 35–43 48 Vapnik, V (1998) Statistical Learning Theory New York: Wiley 49 Tan, P., Steinbach, M., and Kumar, V (2016) Introduction to Data Mining India: Pearson Education 50 Zhang, T., Wu, S., Dong, J et al (2015) Quantitative and classification analysis of slag samples by laser induced breakdown spectroscopy (LIBS) coupled with support vector machine (SVM) and partial least square (PLS) methods Journal of Analytical Atomic Spectrometry 30 (2): 368–374 51 Liang, L., Zhang, T., Wang, K et al (2014) Classification of steel materials by laser-induced breakdown spectroscopy coupled with support vector machines Applied Optics 53 (4): 544–552 52 Huang, J., Dong, M., Lu, S et al (2018) Estimation of the mechanical properties of steel via LIBS combined with canonical correlation analysis (CCA) and support vector regression (SVR) Journal of Analytical Atomic Spectrometry 33 (5): 720–729 53 Dingari, N., Barman, I., Myakalwar, A et al (2012) Incorporation of support vector machines in the LIBS toolbox for sensitive and robust classification amidst unexpected sample and system variability Analytical Chemistry 84 (6): 2686–2694 54 Vítková, G., Prokeš, L., Novotný, K et al (2014) Comparative study on fast classification of brick samples by combination of principal component analysis and linear discriminant analysis using stand-off and table-top laser-induced breakdown spectroscopy Spectrochimica Acta Part B: Atomic Spectroscopy 101: 191–199 55 Poˇrízka, P., Klus, J., Hrdliˇcka, A et al (2017) Impact of laser-induced breakdown spectroscopy data normalization on multivariate classification accuracy Journal of Analytical Atomic Spectrometry 32 (2): 277–288 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 936 56 Castro, J and Pereira-Filho, E (2016) Twelve different types of data normalization for the proposition of classification, univariate and multivariate regression models for the direct analyses of alloys by laser-induced breakdown spectroscopy (LIBS) Journal of Analytical Atomic Spectrometry 31 (10): 2005–2014 57 Hardoon, D., Szedmak, S., and Shawe-Taylor, J (2004) Canonical correlation analysis: an overview with application to learning methods Neural Computation 16 (12): 2639–2664 58 Lu, S., Shen, S., Huang, J et al (2018) Feature selection of laser-induced breakdown spectroscopy data for steel aging estimation Spectrochimica Acta Part B: Atomic Spectroscopy 150: 49–58 59 Friedman, J.H (1997) On bias, variance, 0/1-loss, and the curse-of-dimensionality Data Mining and Knowledge Discovery 1: 55–77 60 Martens, H and Naes, T (1992) Multivariate Calibration New Jersey: Wiley 61 Myakalwar, A., Spegazzini, N., Zhang, C et al (2015) Less is more: avoiding the LIBS dimensionality curse through judicious feature selection for explosive detection Scientific Reports (1): 1–10 62 Nørgaard, L., Saudland, A., Wagner, J et al (2000) Interval partial least-squares regression (iPLS): a comparative chemometric study with an example from near-infrared spectroscopy Applied Spectroscopy 54 (3): 413–419 63 Leardi, R and Nørgaard, L (2004) Sequential application of backward interval partial least squares and genetic algorithms for the selection of relevant spectral regions Journal of Chemometrics: A Journal of the Chemometrics Society 18 (11): 486–497 64 Lu, P., Zhuo, Z., Zhang, W et al (2020) Accuracy improvement of quantitative LIBS analysis of coal properties using a hybrid model based on a wavelet threshold de-noising and feature selection method Applied Optics 59 (22): 6443–6451 65 Wang, T., Jiao, L., Yan, C et al (2019) Simultaneous quantitative analysis of four metal elements in oily sludge by laser induced breakdown spectroscopy coupled with wavelet transform-random forest (WT-RF) Chemometrics and Intelligent Laboratory Systems 194 (11): 103854 66 Duan, H., Ma, S., Han, L et al (2017) A novel denoising method for laser-induced breakdown spectroscopy: improved wavelet dual threshold function method and its application to quantitative modeling of Cu and Zn in Chinese animal manure composts Microchemical Journal 134 (9): 262–269 67 Lu, Y., Guo, H., Shen, T et al (2019) Quantitative analysis of cadmium and zinc in algae using laser-induced breakdown spectroscopy Analytical Methods 11 (48): 6124–6135 68 Patel, D., Singh, R., and Thareja, R (2014) Craters and nanostructures with laser ablation of metal/metal alloy in air and liquid Applied Surface Science 288 (1): 550–557 69 Corsi, M., Cristoforetti, G., Hidalgo, M et al (2005) Effect of laser-induced crater depth in laser-induced breakdown spectroscopy emission features Applied Spectroscopy, 59 (7): 853–860 937 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License References 46 Scope for Future Development in Laser-Induced Breakdown Spectroscopy Yoshihiro Deguchi Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Japan 46.1 Introduction In recent years, technologies that can measure the elemental composition of materials in real time have been eagerly awaited in various industrial and biomedical fields In industrial processes, for example, it is necessary to measure the composition of components in the manufacturing processes to control the quality of raw materials and products However, there is no practical technology or equipment that can measure the elemental composition in real time and online in multidiscipline industrial processes Laser-induced breakdown spectroscopy (LIBS) has been one of the cutting-edge technologies for the challenges mentioned above, and it is an in situ, real-time measurement method for elemental composition in gases, liquids, and solids by focusing a laser beam on targets and measuring the emission spectra from a plasma-formed sample LIBS has the advantage of simple equipment configuration and can detect elemental compositions in a wide range of concentrations from ppb to percentage in gases, liquids, and solids In recent years, the miniaturization and longevity of laser devices have been progressing, and this technological development has been one of the driving forces behind the development of devices using the LIBS principle, further accelerating the development of LIBS applications In LIBS, a plasma of tens of thousands of degrees Celsius is formed in a nanosecond time scale following laser irradiation to an object, and the plasma temperature decreases while interacting with the surrounding environment The elemental emissions generated during this process are detected to identify and quantify the elemental compositions of the object These physical properties complicate LIBS as an analytical method The plasma generated is not uniform in space and time, and there are many cases where local thermodynamic equilibrium is not established Therefore, it is rather difficult to correct the changes in signal intensity influenced by the plasma conditions, and improvement of quantification is one of the important issues in LIBS One of the major drawbacks of LIBS is the difficulty involved in quantitative analysis There are several technical fields for the future development of LIBS both in basic and application viewpoints Thinking about the merits and drawbacks of LIBS, the development of quantitative measurement techniques is one of the most important challenges for future Laser Induced Breakdown Spectroscopy (LIBS): Concepts, Instrumentation, Data Analysis and Applications, Volume 2, First Edition Vivek K Singh, Durgesh K Tripathi, Yoshihiro Deguchi and Zhenzhen Wang © 2023 John Wiley & Sons Ltd Published 2023 by John Wiley & Sons Ltd Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 939 46 Scope for Future Development in Laser-Induced Breakdown Spectroscopy LIBS progress The basic techniques of LIBS are mainly summarized in Chapters 1–6, 8–12, 14–13, and the applications of LIBS are exemplified in Chapters 7, 13, 16–21, and 24–45 There are two categories for the practical realization of LIBS for the future One is the development of the LIBS technique to overcome its drawbacks and develop its merits The other is the hybridization of LIBS with other methods to meet the demand of measurement specifications The applications of LIBS have been widely expanding from the utilization on Earth to outer space (Chapter 43), and the expected LIBS performance has created a lot of expectations for the coming digital transformation age 46.2 Development of LIBS Techniques As discussed in Chapter 22, there are several conventional methods to compete with LIBS as an elemental analysis method Inductively coupled plasma atomic emission spectroscopy (ICP-AES), inductively coupled plasma-mass spectrometry (ICP-MS), and X-ray fluorescence analysis (XRF) are typical methods that have been applied to similar fields as LIBS applications In real-time monitoring applications of elemental composition, XRF often competes with LIBS The merits of LIBS include fast response and excellent spatial resolution with a wide range of measurement conditions, including in situ measurement It is rather rare for LIBS to compete with other laser diagnostics because LIBS is an elemental (and sometimes molecular) analytical method using laser breakdown phenomena The future of LIBS relies extensively on the development of the fundamental technology of LIBS and its applications Figure 46.1 shows the evolution of LIBS signals according to the delay time from laser irradiation LIBS signal appears during the plasma cooling process, and this process is usually unstable because of the complicated physical phenomena containing the plasma physics and flow dynamics Several important basic characteristics Laser-induced plasma Emission Laser Laser Intensity 106 Noise (Black body) 104 102 Atomic emission 100 Time Noise Noise Wavelength Figure 46.1 LIBS signal evolution ×10000 Atomic emissions Wavelength Intensity ×100 Intensity ×1 Atomic emissions Noise Wavelength Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 940 affect LIBS performances as shown below from (1)–(5) Among them, the advancement of data-processing algorithms will widen the applicability of LIBS to many fields as discussed in Chapters 12 and 15 1) Stability of plasma As mentioned above, the signal intensity of LIBS depends on several factors, including plasma temperature, plasma density, pressure, and so on as shown in Chapter The fluctuation of its signal is an intrinsic characteristic in LIBS The signal correction techniques can reduce this fluctuation of LIBS signal to some extent as discussed in Chapter Since the correction technique can be applied within limited experimental conditions, experimental parameters, such as laser fluence and measured material conditions have to be controlled within defined values In solid material analysis, it is also important to measure the target with a fresh (or controlled) surface in each laser shot because the laser–target surface interaction is the initiation of the LIBS physical phenomena 2) Non uniformity of plasma The laser-induced plasma has a structure to it In the plasma generation process, the plasma structure depends largely on the laser density pattern and measured material conditions After plasma generation, the induced plasma expands rapidly into an ambient environment Therefore, the core of the plasma is usually hotter than its edge, and the LIBS signal depends on the measurement area across the plasma In this sense, the correction method mentioned above also includes the effects of plasma non uniformity in it The self-absorption effect is also induced by the non uniformity of plasma, which often causes the degradation of the quantitative detection ability of LIBS 3) Matrix effects Matrix effects are the combined effects of all components that existed in plasma Changes in these components may cause the alteration of LIBS signal intensity even if the number density of the measured species is the same in each sample Matrix effects intrinsically exist in LIBS as shown in Chapter 5, and they are usually corrected by experimental calibration and/or data processing 4) Signal enhancement Signal enhancement methods are important to improve the detection limit of LIBS There are several methods to improve the LIBS signal intensity, which include the multiple pulses LIBS technique (Chapter 4) and nanoparticle-enhanced LIBS (Chapters and 9) Signal enhancement methods should be employed in consideration of application conditions 5) Data processing The data-processing technique is one of the most important key technologies for quantitative LIBS analysis Because of the recent advancement of computing speed and data-processing methods, such as machine-learning algorithm, as discussed in Chapter 15, the data-processing technique has played a key role in achieving the quantitative capability of LIBS Its advancement will give us a specific answer to the academic challenges of LIBS LIBS applications are summarized in Chapters 7, 13, 16–21, and 24–45, and their requirements for LIBS devices depend on each application There are important factors for 941 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 46.2 Development of LIBS Techniques 46 Scope for Future Development in Laser-Induced Breakdown Spectroscopy LIBS applications and the common factors that affect the LIBS device performances are shown below 1) Performance of laser and detector The key components of LIBS are the laser and its detector Many of the LIBS applications have used pulsed yttrium–aluminum garnet lasers and intensified charge-coupled device detectors; however, the demands for these two components have been rapidly increasing Compactness, high-performance, cost-competitiveness, and ruggedness are always required for LIBS applications The gating performance is also an important factor of LIBS detectors Now portable and standoff LIBS systems have been developed and applied to various fields, and the performance of laser and detector becomes a key factor for many LIBS applications 2) Cleanliness of measurement windows and optics In LIBS, contamination of measurement windows is less critical than other laser diagnostics because the signal intensity ratio is usually used for elemental composition analyses The attenuation of LIBS signals by windows is automatically canceled if its influence is the same for each LIBS signal Considering the measurement stability and soundness of windows, however, the cleanness of windows and LIBS optics has to be maintained as much as possible, especially in practical applications 3) Autofocus technology Laser fluence is one of the most important factors for LIBS plasma formation Therefore, it is important to focus the laser beam appropriately on the target The autofocus technology is necessary to maintain the appropriate laser fluence for plasma formation in case the distance between the LIBS device and the measured sample changes Autofocus technologies are developed in many fields and the employment of autofocus technology with LIBS will widen the applicability of LIBS to many applications 46.3 Hybrid Method of LIBS and Other Methods The hybrid technology of LIBS and other methods has been one of the prospective solutions for the future development of LIBS LIBS is an elemental analytical method, and hybridization of LIBS with other methods will solve some of the challenges posed by LIBS applications As shown in Chapter 23, Raman spectroscopy has been intensively combined with LIBS to cover elemental and molecular analyses Compared with non optical methods, optical measurement methods will have a favorable and appealing aspect to expand the applicable scope of LIBS Table 46.1 shows the optical measurement technologies that can be combined with LIBS for the enhancement of analytical performances Raman spectroscopy, laser-induced fluorescence, and absorption spectroscopy can be combined with LIBS to simultaneously analyze the molecular (or chemical-bonding state) information Mass spectrometry can be used to enhance the detectability of elements and molecules [1] As one of the absorption spectroscopy techniques, terahertz (THz) technology can be used with LIBS Terahertz (THz) technology is not the name of a specific measurement technology, but the collective term describing methods employing terahertz waves Terahertz waves are electromagnetic waves with a frequency of around THz (wavelength: 300 μm) One of the attractive characteristics of terahertz waves for advanced Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 942 Characteristics of optical measurement technologies that can be combined with LIBS Method Measurement item Measurement Reliability dimension System cost of laser LIBS ● Concentration (elemental composition) Point (2D: scanning) Medium Raman spectroscopy ● Temperature Concentration Point (1D, 2D: scanning) Optical coherence tomography ● Distance 3D structure Laser-induced fluorescence ● Absorption spectroscopy ● Mass spectrometry Calibration based on theories Multi-species detection Insitu LowHighDetection measurement pressure pressure limit Excellent Difficult (calibration curve, matrix effect) Excellent Medium Medium Ppb% Low–medium Medium– excellent Easy Excellent Excellent Poor Excellent % 3D Low–medium Excellent — Poor Excellent — — — Temperature Concentration 2D Medium–high Poor Difficult Poor Excellent Excellent Medium Ppm% Temperature Concentration Line of sight (2D using CT) Low Excellent Easy (selfcalibration) Poor Excellent Excellent Poor Ppm% ● ● Concentration Point High Poor Easy (internal standardization) Excellent Based on sampling Based on sampling Based on sampling Ppt–ppb% ● ● ● Medium Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Table 46.1 46 Scope for Future Development in Laser-Induced Breakdown Spectroscopy applications is that terahertz waves can penetrate many nonmetals [2, 3] Using this feature of terahertz waves, it is possible to see through objects Papers, cardboard, plastics, and clothing materials are transparent in the range of terahertz waves, and there have been extensive studies in security [4, 5], pharmaceutical applications [6], and medical applications [7, 8] The combination of LIBS with THz technology can provide a wealth of information on the measurement object because LIBS can analyze the surface of solid materials Optical coherence tomography (OCT) can be a good partner with LIBS OCT is an interferometric technology that detects a backscattered light from an object using low interference laser light OCT provides information of the backscattered light intensity as a function of depth from the object’s surface and the object’s surface structure (distance) [9] Light from a low coherence broad bandwidth light source is split into two beams that are used as sample and reference light Sample light entering the object is backscattered with different time delays according to the object structure, i.e the depth from the object surface The backscattered light and reference light are recombined to form an interference pattern by moving the mirror of the reference light The interference pattern only arises when the path difference of signal and reference lies within the coherence length of light Though OCT is a 1D measurement technology, it is easy to construct a 3D image of the object structure by a two-dimensional scanning of the light The axial and transverse resolutions of OCT are in the micrometer range There have been extensive studies of OCT in medical applications [9–11], and it has also been applied to industrial fields [12–14] Since OCT can measure the object’s surface structure (distance), the 3D structure of the object is a function of depth from the object’s surface at high speeds OCT can provide precious information for LIBS, such as the distance information to the target, and the combination of LIBS with THz technology can provide deeper analytical data References Wang, Z., Deguchi, Y., Yan, J., and Liu, J (2015) Comparison of the detection characteristics of trace species using laser-induced breakdown spectroscopy and laser breakdown time-of-flight mass spectrometry Sensors 15: 5982–6008 Kawase, K., Shibuyaa, T., Hayash, S., and Suizu, K (2010) THz imaging techniques for nondestructive inspections Comptes Rendus Physique 11 (7–8): 510–518 Sizov, F.F (2010) THz radiation sensors Opto-Electronics Review 18 (1): 10–36 Leahy-Hoppa, M.R., Miragliotta, J., Osiander, R et al (2010) Ultrafast laser-based spectroscopy and sensing: applicationsin LIBS, CARS, and THz spectroscopy Sensors 10: 4342–4372 Leahy-Hoppa, M.R., Fitch, M.J., Zheng, X et al (2007) Wideband terahertz spectroscopy of explosives Chemical Physics Letters 434 (4–6): 227–230 Wu, H., Heilweil, E.J., Hussain, A.S., and Khan, M.A (2007) Process analytical technology (PAT): quantification approaches in terahertz spectroscopy forpharmaceutical application Journal of Pharmaceutical Sciences 97 (2): 970–984 Ashworth, P.C., Pickwell-MacPherson, E., Provenzano, E et al (2009) Terahertz pulsed spectroscopy of freshly excised human breast cancer Optics Express 17 (15): 12444–12454 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 944 Nishizawa, J., Sasaki, T., Suto, K et al (2005) THz imaging of nucleobases and cancerous tissue using a GaP THz-wave generator Optics Communications 244 (1–6): 469–474 Bouma, B.E., Yun, S.-H., Vakoc, B.J et al (2009) Fourier-domain optical coherence tomography: recent advances toward clinical utility Current Opinion in Biotechnology 20 (1): 111–118 10 Sowa, M.G., Popescu, D.P., Werner, J et al (2007) Precision of Raman depolarization and optical attenuation measurements of sound tooth enamel Analytical and Bioanalytical Chemistry 387 (5): 1613–1619 11 Na, J., Baek, H.J., Ryu, S.Y et al (2009) Tomographic imaging of incipient dental-caries using optical coherence tomography and comparison with various modalities Optical Review 16 (4): 426–431 12 Serrels, K.A., Renner, M.K., and Reid, D.T (2010) Optical coherence tomography for non-destructive investigation of silicon integrated-circuits Microelectronic Engineering 87 (9): 1785–1791 13 Prykaeri, T., Czajkowski, J., Alarousu, E., and Myllylae, R (2010) Optical coherence tomography as an accurate inspection and quality evaluation technique in paper industry Optical Review 17 (3): 218–222 14 Wiesner, M., Ihlemann, J., Muller, H.H et al (2010) Optical coherence tomography for process control of laser micromachining The Review of Scientific Instruments 81 (3): 033705 945 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License References Index a Ablation 3–16, 22–24, 39, 69–76, 91–94, 141–145, 278, 358–360, 534–536, 863–865 Acetaminophen 214, 218–222, 224 Aerosol 5, 58, 89, 147, 156, 476, 567, 755–762 AES 89, 91, 177, 338–389, 394–396, 461 Alloy 21, 65, 105, 106, 141, 147, 153, 193, 254, 333, 397, 404, 421, 625–627, 832, 858 Ambient gases 462, 652 Amended methods 100, 101 Anthropogenic 781 APXS 853 Archaeological artifacts 539 Artificial neural network 230, 236, 243, 340, 587, 598, 676 Artificial neuron 314, 315 Aspirin 214, 218–222, 224 Atmospheric pressure 56, 67, 93, 113, 141, 163, 466, 571, 668, 858 Atomic orbital 167 Avalanche ionization 6, b Bacteria 21, 58, 431–434, 437, 496, 512, 702, 705–710, 745–750 Bacterial pathogens 747, 749, 750, 754 Baseline 257–258, 280, 875, 928 Biofouling 431, 432, 434, 437–444 Bioimaging 729–740 Biomass 331, 334, 335, 338, 340, 342, 344, 346–350 Bremsstrahlung 7, 11, 34, 129, 355, 551, 617, 757, 893, 903 Broadband LIBS 598, 601, 605, 648, 749 c Calcified tissues 57, 58, 715, 737 Cavitation bubbles 55 CCD 139, 146, 155, 455, 464, 476, 495, 503, 673, 826, 852, 893, 928, 930 ChemCam 513–515, 646, 852, 856, 857 Chemical hazards 701, 703 Chemometric analysis 21, 594, 596, 598, 749 Chemometric methods 241–242, 277, 281, 594, 600, 687, 772, 795–798, 855 Coal 319, 331, 334–336, 340, 342, 347–350, 418, 424, 457, 465, 581–588 Collinear DP-LIBS 67, 68, 73, 81, 535 Continuum emission 6, 9, 50, 108, 114, 390, 418, 481, 495, 498 Continuum radiation 39, 355 Coulomb explosion 3, 4, 8, 198 Covariance 252, 432, 620 Cross-validation 262–268, 281–282, 284, 307, 423, 620, 870, 920, 922 Cultivation 730, 777, 781, 796 Cultural heritage 15, 70, 81, 141, 171, 176, 453, 487, 496, 510, 521, 539, 554, 623, 632, 863 Czerny–Turner spectrographs 494, 499 Laser Induced Breakdown Spectroscopy (LIBS): Concepts, Instrumentation, Data Analysis and Applications, First Edition Vivek K Singh, Durgesh K Tripathi, Yoshihiro Deguchi and Zhenzhen Wang © 2023 John Wiley & Sons Ltd Published 2023 by John Wiley & Sons Ltd Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 947 Index d g Degenerate 887 Diamond 214, 218, 287, 288, 291, 297, 298, 300, 595 Dichroic mirrors 152, 517, 560, 561, 570 Directionality 11, 356, 360, 362, 374 Doppler broadening 469, 758 Doppler effect 40, 41, 462 Dual-pulse LIBS 20, 422, 481, 672, 798 Garnets 598, 687 Gated 139, 452, 454, 488, 489, 495, 498, 499, 510, 521, 617, 720 Gaussian profile 40, 110 Gem stones 287–289 Geochemical fingerprinting 683–690 Geometries and configurations 67 Geoscience 608, 685 Glasses 56, 388–395, 400, 418, 419, 647, 746, 824 Grains 216, 217, 488, 507, 795, 809, 816, 817 Ground state 98, 185, 191, 355, 363, 366–368, 375, 466, 851 e Echelle spectrometers 111, 113, 114, 149, 494 Electron temperature 49, 50, 129, 187, 192, 202, 553, 585, 654 Elemental mapping 137, 202, 437, 440, 594, 608, 647, 658, 827 Emerald 218, 287–288, 292, 298–300, 687 Energy-dispersive X-ray 389, 398, 402, 462, 472, 520, 784 Energy level 39, 53, 185, 367, 374, 448, 469, 534, 562, 584 Explosives 81, 83, 141, 150, 153–160, 382, 416, 667–679, 701, 748, 878 h Haemangioma 736 Heat resistant steel 883–887, 893, 902, 919, 921, 927, 933 Herbal products 808 High energy materials 149, 669, 670, 677, 864, 873 HMX 150, 153, 668–669, 674, 678 Humification 768–770 Hyphenated 5, 447, 450–453, 456, 562 f Femtosecond pulses 138, 150, 153, 155, 158, 183, 203, 863, 873 Femtoseconds 72, 138, 534 Filamentation 14–17, 142, 144, 153, 154, 498, 748 Fingerprint 58, 147, 457, 601, 645, 683, 684, 747, 748, 903 Fluorescence spectroscopy 447, 450, 462, 495 Flux 34–35, 89, 387 Food science 781, 784 Free-bound transitions 45 Fruits 202, 794, 811–813 FTIR 456–457, 588 Fuel retention 651–654 Full-spectrum multivariate 213, 215, 217–218 FWHM 193–194, 196, 469, 759, 762, 825, 844, 864 i ICCD 12–13, 139, 141, 143, 158, 184, 361, 452, 489, 495, 503–506, 815, 852, 896–897 Impurities 18, 108, 175, 290, 388–390, 392, 395, 407, 416, 598, 646, 649, 651, 657, 716, 772, 834 Infrared spectroscopy 150, 214, 257, 288, 510, 796 Integrated Raman 490, 493–496, 498, 499, 501, 507, 514, 519–521, 857 Internal standard 233, 258, 259, 419, 420, 563, 869–871, 931 Inverse bremsstrahlung 7, 73, 102, 129, 355, 551 Irradiance 7, 46, 73, 74, 125, 129, 143, 171, 201, 461, 566, 756, 826 Isotopic 16, 17, 278–279, 283, 285, 289, 643–45, 650 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 948 j Joules 159, 382 Jupiter 520, 861 k Keldysh parameter 183, 198 K-means clustering 318, 600, 607 l Laser fluence 7, 9, 91, 100, 155, 170, 185, 190, 198, 259, 278, 400, 651, 755 Laser micromachining 453, 629 Lasing 355–361, 363, 366–368, 373–376, 382 LIBS sensor 150, 157, 334, 511, 560, 569, 748 LIDAR 16, 27, 505, 506, 520 Limitations 5, 6, 48, 51, 176, 249, 251, 448, 450, 677, 798, 807, 859, 863 Limit of detection (LoD) 18, 52, 141, 184, 251, 267, 388, 419, 457, 462, 567, 623, 782, 844 Linear stark broadening 48 Line strength 893, 895 LIP 18, 19, 33, 39, 125–33, 355–62, 382, 519, 534, 553, 617, 618, 866 Local field enhancement 168 Lorentzian profile 41, 110 LTE 38–40, 47, 49, 52–55, 89–98, 108, 111, 112, 389–393, 466, 759, 762, 867 m Machine learning 149, 151, 154, 158, 229, 233, 266, 586, 616, 619, 673–677, 772, 911 Mahalanobis distance 596 Marine 141, 290, 431, 437, 444 Mars 141, 146, 147, 252, 498, 506, 513–516, 772, 851–858 Mars rover curiosity 856 Mars science laboratory 852 Matrix effect 5, 48, 49, 215, 242, 250, 349, 551, 582–586, 673, 783, 855, 873 Meat 738, 784, 786, 792, 793, 809 Metastable phases 755 Meteorite samples 854 Microanalysis 420, 424, 488, 824–826 Milk 252, 784, 786, 791, 793, 794, 798, 809, 810 Mode-locking 138 Molecular formation in LIP 126, 127 Moon 519, 520, 855, 856, 858 Multi-elemental analysis 417, 467, 487, 623 Multiphoton absorption 6, 562 Multiple linear regression 250, 251 Multiple pulse LIBS 65, 75, 535 Multivariate analysis 213–15, 217–18, 224, 241–242, 248, 287, 289–298, 338, 508, 594, 669, 748 n Nanoaerosols 755, 762 Nanoparticles 55, 155, 158, 171, 192–197, 202–205, 481, 512, 541, 709, 755–759, 811 Nanoseconds 33, 39, 56, 72, 489–91, 495, 518, 905 NASA 498, 499, 515, 519, 852, 856, 857 NELIBS 155, 158, 165, 170–179, 481, 541, 706, 731 NIR spectroscopy 447–450 Nonlinear stark broadening 47 Normalization 41, 52, 233, 242, 251, 258–261, 268, 338, 344, 584, 718, 815, 929 Nuclear fission 277, 645 Nuclear waste 423, 646, 648 o Optical breakdown 141 Optical fiber 146, 177, 184, 242, 334, 560, 570, 649, 723–725 Optical multichannel analyzer 774 Optical surface 387, 396, 407 Orange software 279, 283 Orthogonal DP-LIBS 68–70 Oscillator strength 39, 102 Osteoporosis 781 949 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Index Index p Parallel DP-LIBS 70, 71 Partial least square regression (PLSR) 215, 223, 595 Partial least squares discriminant analysis 255, 256, 282, 518, 616, 619, 632, 673, 688, 748, 812, 855 Paschen–Runge spectrometer 826, 832 Persistent spectral lines 463–464 PETN 147, 157, 668, 669, 673, 676 Pharmaceuticals 213, 215, 218, 229, 236, 703, 863 Phase explosion 3, 11, 91 Picosecond 3, 34, 198, 201, 504, 534, 634, 792 Pixel 688, 730, 896, 905 Plasma emissions 46, 138, 139, 146, 155, 184, 187, 333, 355, 361, 432, 933 Plasma ignition 723, 782 Plasma shielding 7, 73, 128, 130, 534, 535, 562 Plasma temperature 46–52, 73–74, 101, 173, 185, 192, 397, 465–467, 535, 553, 583–585, 721, 939, 941 Plasmon coupling 167, 172 Plastic 157, 215, 229, 311, 431, 449, 452, 513, 615 Polarization 356, 360, 362, 370–377, 382 Principal component analysis (PCA) 149, 184, 202, 215, 230–234, 244, 432, 453, 518, 618, 705, 902 Process optimization 397 Proton-induced X-ray 289, 461, 473 q Quantum number 56 Quasi-static approximation 167, 168, 170 r Radiative recombination 36–40, 45, 51, 54–56, 108, 561 Raman spectroscopy 18, 165, 259, 447, 448, 450, 456, 487–502, 507, 510–514, 520, 615, 649, 669–672, 705, 706 Rare earth 289, 297, 415, 416, 418, 456, 562, 606, 647, 648, 658, 683 RDX 147, 150, 153, 156, 668, 669, 673, 676, 678, 876 Recycling 538, 615, 823, 824, 829, 832 Resonance lines 402, 467, 718 R-LIBS 154 Rolling mill 537, 827 RSD 190, 250, 282, 721, 913, 914 Ruby 65, 195, 198, 218, 287, 289–291, 294–300, 415, 595 s Salts 56, 420, 715–722, 725, 793 Sapphire 289–291, 294–298, 595, 864 S/B ratio 481 Scaling 251, 252, 259–262, 280, 307, 565 Scanning microanalysis 825 Scope 6, 309, 319, 690, 873, 939, 942 Sedimentary 196, 199, 216, 291, 565, 581, 601, 603–607, 687 Selection rules 113 Self-absorption 39, 90, 95, 100–101, 113–116, 259, 338, 389, 402, 407, 466, 585, 718, 809 Shock wave 11, 13, 17, 56, 172, 199, 562, 565, 749, 893 Signal enhancement 17, 19, 65, 67, 70, 72, 75–80, 195, 200, 421, 561, 651, 941 Simulated emission 356 S/N ratio 6, 144, 452, 863, 865 Space exploration 851–859 Spectrometers 111–114, 139, 149, 156, 158, 230, 466, 496, 515, 559, 650 Spontaneous emission 36, 99, 114, 356, 361, 381, 853 Standoff LIBS 137–150, 154–158, 416, 566, 748, 854 Stark broadening 47, 48, 55, 99, 111, 114, 121, 402, 405, 466, 491, 553, 654, 758 Stoichiometry 129, 176 Submerged 57, 542, 560, 562–566 Support vector machines 183, 281, 305, 311, 598, 707 Surface ablation 456 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 950 t w Tag-LIBS 729, 738, 739 Tea 795, 811, 815 Teramobile 14 Thin films 382, 387–389, 395–397, 400, 404, 407, 791 Time-gating 515 Time-of-flight mass spectroscopy 461, 476 TNT 147, 148, 150, 153, 156–157, 668, 676–478 Transition probability 48–52, 109, 113, 331, 467, 468, 719, 758, 868, 925 Tunneling ionization Wavefunction 167 Wavelength ranges 243, 599, 903–905 Whole spectra 146, 185, 244, 258, 539, 769 u Ultraviolet 8, 90, 101, 112, 141, 401, 488, 669, 670, 717 Underwater LIBS 554, 561–567, 572 Underwater samples 80 Uranium 144, 148, 150, 157, 277–280, 646, 647, 650, 656–658, 772 v Vacuum pump 476, 645 Vegetables 202, 786, 794–795, 798, 809, 811 Venus 505, 519, 520, 552, 857 x X-ray computed tomography (HRXCT) data 601 X-ray diffraction 510, 595, 610, 853 X-ray fluorescence 289, 299, 338, 388, 424, 474, 510, 581, 617, 781, 808, 839, 853 X-ray photoelectron spectroscopy 388, 729 y Yield 9, 18, 19, 133, 199, 294, 307, 876, 885 Yttrium 417, 418, 424, 652, 739, 864, 942 z Zeolites 598, 599 Zinc 105, 157, 189, 196, 387, 402, 477 Zwitterionic gold nanoclusters 743 951 Downloaded from https://onlinelibrary.wiley.com/doi/ by THU VIEN - Fiji - Hinari access , Wiley Online Library on [30/03/2023] See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Index