Download or read book Applications of Infrared Laser Spectroscopy to Breath Analysis written by Beth L. Cummings and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this thesis is concerned with development of spectroscopic detection methods based on absorption spectroscopy using semiconductor lasers, with particular ref- erence to the field of medical diagnostics through breath analysis. The first part of this thesis deals with the design and testing of a prototype analyser for simultaneous monitoring of the exchange gases 02, C02 and H20 in breath. The aim of this analyser is to provide information required to monitor respiration, with potential use in intensive care monitoring or during anaesthesia. The relatively high concentrations of these gases in breath and read- ily available diode laser sources make detection in the near-infrared (NIR) ideal. However, the relatively weakly absorbing A-band 02 transitions at 760 nm require the application of a sensitive spectroscopic method, cavity enhanced absorption spectroscopy (CEAS). In contrast, CO2 and H20 are monitored using direct single pass absorption spectroscopy, with transitions arising from the 21/1 + 1/3 band at 2 uu: and 1/1 + 1/3 band at 1.3 p,m, re- spectively. It has been demonstrated that these gases can be detected simultaneously over a short pathlength (2.74 - 4 cm) in the respiratory flow by combining various spectroscopic methodologies and real-time data analysis. This analyser is shown to offer a viable alter- native for monitoring respiration, exhibiting absolute detection limits of changes of 0.26 % O2, 0.02 % CO2 and 0.003 % H20 with a 10 ms time resolution, which are comparable to current mass spectrometry based methods, but without their inherent delays. Following this, investigations into the detection of the main gas constituents in breath in the NIR employing noise-reduction modulation based spectroscopic techniques, namely wavelength and frequency modulation (WMS and FMS respectively) are also reported. The described WMS studies on water at 1.37 ust: provide a demonstration of conventional WMS detection, as well as a "proof-of-principle" example of a relatively new approach to calibrat- ing the non-absolute information obtained from a WMS absorption signal. Typically WMS spectra are calibrated using mixtures of known gas concentrations or an absolute direct absorption spectrum where possible. In this work however, a self-calibrating method, the phasor decomposition method (PDM), is employed and the returned concentration from this ~alibration is compared to direct absorption measurement. From this, the calculated concentration using the PDM is found to differ by 9 % from the concentration value ob- tained by direct absorption, providing an alternative method of calibration for when direct absorption measurements are not possible. The use of FMS in the NIR is also demon- strated as a potential alternative to CEAS for monitoring O2 at 760 nm. FMS detection is performed on atmospherically broadened 02 and a time-normalised O!min(t) of 2.45x10-6 cm-1 s~ is obtained, which is two orders of magnitude less sensitive than the value of 1 O!min(t) = 2.35x10-8 cm "! S2 obtained with CEAS. This combined with the experimental I requirements of an FMS system, make its use for detection of 02 a less practicable option compared to CEAS for real-time breath analysis. The latter work in this thesis involves a change in focus to detection of trace gases in breath in the mid-infrared (MlR). The move of spectroscopic detection to the MlR exploits the larger absorption cross-sections available in this region, and to achieve this, a relatively new form of semiconductor laser, the quantum cascade laser (QCL) is used. The design of a continuous wave QCL spectrometer at 8 usx: and its operating characteristics are demon- strated and improvements in its performances are also discussed. This QCL system is then utilised to demonstrate the potential of monitoring species in breath, namely the narrow- band absorber methane and the broadband absorber acetone, taking into consideration the potential interference from other absorbing species in breath and the different spectroscopic characteristics exhibited by these molecules. Finally, the potential to further improve the sensitive detection of trace gases in breath in the MlR is also investigated with studies on the use of CEAS and multipass cells. In this work, the molecule of interest is the biomarker OGS, using transitions of the 2V2 band at 1031 cm-I, that are probed using a 10 usx: QCL. The application of CEAS in the MlR is not as well developed as in the NIR, and the experimental consequences of using optical cavities at these wavelengths, where equipment tends to be more limited, are investigated and sensitivities discussed in the context of other literature. The experimental procedure of optimising a cavity for CEAS using the off-axis alignment method is also studied in detail, as well as the addition ofWMS to further improve the signal quality. An effective absorption pathlength of ,....., 100 m was achieved in the cavity, with a bandwidth reduced O!min(BW) 1 of 1.7x10-7 cm"? HZ-2 using WMS CEAS achieved. With the poorer quality optics and limitations in equipment in the MlR for CEAS experiments, the use of a multipass cell, a 238 m Herriott cell, is also investigated as an alternative to the use of an optical cavity at 10 tui". Detection of OCS using direct absorption and WMS is demonstrated in the 1 Herriott cell, achieving O!min(BW) = 2.03xlO-8 cm "! HZ-2 using WMS. This shows an improvement in sensitivity compared to WMS CEAS, and also shows the potential for future work on biomarker detection, as it approaches the r-- ppb levels required for breath analysis.
Download or read book Laser based Mid infrared Sources and Applications written by Konstantin L. Vodopyanov and published by John Wiley & Sons. This book was released on 2020-06-25 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important guide to the major techniques for generating coherent light in the mid-infrared region of the spectrum Laser-based Mid-infrared Sources and Applications gives a comprehensive overview of the existing methods for generating coherent light in the important yet difficult-to-reach mid-infrared region of the spectrum (2–20 μm) and their applications. The book describes major approaches for mid-infrared light generation including ion-doped solid-state lasers, fiber lasers, semiconductor lasers, and laser sources based on nonlinear optical frequency conversion, and reviews a range of applications: spectral recognition of molecules and trace gas sensing, biomedical and military applications, high-field physics and attoscience, and others. Every chapter starts with the fundamentals for a given technique that enables self-directed study, while extensive references help conduct deeper research. Laser-based Mid-infrared Sources and Applications provides up-to-date information on the state-of the art mid-infrared sources, discusses in detail the advancements made over the last two decades such as microresonators and interband cascade lasers, and explores novel approaches that are currently subjects of intense research such as supercontinuum and frequency combs generation. This important book: • Explains the fundamental principles and major techniques for coherent mid-infrared light generation • Discusses recent advancements and current cutting-edge research in the field • Highlights important biomedical, environmental, and military applications Written for researchers, academics, students, and engineers from different disciplines, the book helps navigate the rapidly expanding field of mid-infrared laser-based technologies.
Download or read book Mid Infrared Coherent Sources and Applications written by Majid Ebrahim-Zadeh and published by Springer Science & Business Media. This book was released on 2008-01-02 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering fundamental principles and the state of the art, this is a collection of reviews from experts in mid-infrared (mid-IR) coherent sources. Among the sources covered are optical parametric oscillators, difference frequency generators, and the most recent broadband crystalline, quantum cascade, and fiber lasers. The authors show how advances in mid-IR science and technology make these sources indispensable for a variety of applications.
Download or read book State of the Art Laser Spectroscopy and its Applications Volume II written by Yufei Ma and published by Frontiers Media SA. This book was released on 2023-02-09 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser in Environmental and Life Sciences written by Peter Hering and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive reference work illustrates the state of the art of laser-induced analytical methods in environmental and life sciences via an interdisciplinary approach. Ky techniques for remote sensing in the atmosphere as well as diagnostic methods for soil, water and air contamination and exhaled breath are described. Each a prominent scientist, the authors report on their current research; demonstrate that multi-disciplinary applications are possible; and employ examples on how existing environmental diagnostic methods have found their way into the life sciences.
Download or read book Mid infrared Semiconductor Optoelectronics written by Anthony Krier and published by Springer. This book was released on 2007-05-22 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optoelectronic devices operating in the mid-infrared wavelength range offer applications in a variety of areas from environmental gas monitoring around oil rigs to the detection of narcotics. They could also be used for free-space optical communications, thermal imaging applications and the development of "homeland security" measures. Mid-infrared Semiconductor Optoelectronics is an overview of the current status and technological development in this rapidly emerging area; the basic physics, some of the problems facing the design engineer and a comparison of possible solutions are laid out; the different lasers used as sources for mid-infrared technology are considered; recent work in detectors is reviewed; the last part of the book is concerned with applications. With a world-wide authorship of experts working in many mid-infrared-related fields this book will be an invaluable reference for researchers and graduate students drawn from physics, electronic and electrical engineering and materials science.
Download or read book Laser Spectroscopy and its Applications written by Richard W. Solarz and published by Routledge. This book was released on 2017-11-22 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bringing together scattered literature from a range of sources, Laser Spectroscopy and ItsApplications clearly elucidates the tools and concepts of this dynamic area, and providesextensive bibliographies for further study.Distinguished experts in their respective fields discuss resonance photoionization, laser absorption,laser-induced breakdown, photodissociation, Raman scattering, remote sensing,and laser-induced fluorescence. The book also incorporates an overview of the semiclassicaltheory of atomic and molecular spectra.Combining background at an intermediate level with an in-depth discussion of specifictechniques, Laser Spectroscopy and Its Applications is essential reading for laser and opticalscientists and engineers; analytical chemists; health physicists; researchers in optical,chemical, pharmaceutical, and metallurgical industries. It will also prove useful for upperlevelundergraduate and graduate students of laser spectroscopy and its applications, andin-house seminars and short courses offered by firms and professional societies.
Download or read book Laser Spectroscopy for Sensing written by Matthieu Baudelet and published by Elsevier. This book was released on 2014-02-15 with total page 601 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser spectroscopy is a valuable tool for sensing and chemical analysis. Developments in lasers, detectors and mathematical analytical tools have led to improvements in the sensitivity and selectivity of spectroscopic techniques and extended their fields of application. Laser Spectroscopy for Sensing examines these advances and how laser spectroscopy can be used in a diverse range of industrial, medical, and environmental applications. Part one reviews basic concepts of atomic and molecular processes and presents the fundamentals of laser technology for controlling the spectral and temporal aspects of laser excitation. In addition, it explains the selectivity, sensitivity, and stability of the measurements, the construction of databases, and the automation of data analysis by machine learning. Part two explores laser spectroscopy techniques, including cavity-based absorption spectroscopy and the use of photo-acoustic spectroscopy to acquire absorption spectra of gases and condensed media. These chapters discuss imaging methods using laser-induced fluorescence and phosphorescence spectroscopies before focusing on light detection and ranging, photothermal spectroscopy and terahertz spectroscopy. Part three covers a variety of applications of these techniques, particularly the detection of chemical, biological, and explosive threats, as well as their use in medicine and forensic science. Finally, the book examines spectroscopic analysis of industrial materials and their applications in nuclear research and industry. The text provides readers with a broad overview of the techniques and applications of laser spectroscopy for sensing. It is of great interest to laser scientists and engineers, as well as professionals using lasers for medical applications, environmental applications, military applications, and material processing. Presents the fundamentals of laser technology for controlling the spectral and temporal aspects of laser excitation Explores laser spectroscopy techniques, including cavity-based absorption spectroscopy and the use of photo-acoustic spectroscopy to acquire absorption spectra of gases and condensed media Considers spectroscopic analysis of industrial materials and their applications in nuclear research and industry
Download or read book Breath Analysis written by Stefan Weigl and published by Springer Nature. This book was released on 2022-11-14 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume highlights the potentials as well as the limits and challenges of human breath analysis and describes the current efforts made to advance this promising technology from bench to bed. Human breath analysis is a young, interdisciplinary and innovative research field aiming to provide a smart and non-invasive diagnostic tool, which can be used for screening, detecting and monitoring of diseases or metabolic disorders. This book presents different approaches for breath analysis including real-time and offline mass spectrometry as well as optical and semiconductor gas sensing methods. Besides, the role of smart algorithms to improve the performance of those technologies and the importance of pulmonary function diagnostics for more reliable and meaningful breath analysis are highlighted. Finally, current application scenarios and future perspectives of breath analysis and pulmonary functioning tests are addressed. The volume is useful for researchers, who are new in the field, to easily get an overview of the current status and the challenges present in human breath analysis. Topics from fundamental research over targeted sensor development and application scenarios are described. Thus, this volume covers all development stages providing support and inspiration for engineers, medical doctors and scientists from various fields.
Download or read book New Enhanced Sensitivity Infrared Laser Spectroscopy Techniques Applied to Reactive Plasmas and Trace Gas Detection written by Stefan Welzel and published by Logos Verlag Berlin GmbH. This book was released on 2009 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Infrared laser absorption spectroscopy (IRLAS) employing both tuneable diode and quantum cascade lasers (TDLs, QCLs) has been applied with both high sensitivity and high time resolution to plasma diagnostics and trace gas measurements. TDLAS combined with a conventional White type multiple pass cell was used to detect up to 13 constituent molecular species in low pressure Ar/H2/N2/O2 and Ar/CH4/N2/O2 microwave discharges, among them the main products such as H2O, NH3, NO and CO, HCN respectively. The hydroxyl radical has been measured in the mid infrared (MIR) spectral range in-situ in both plasmas yielding number densities of between 1011 ... 1012 cm-3. Strong indications of surface dominated formation of either NH3 or N2O and NO were found in the H2-N2-O2 system. In methane containing plasmas a transition between deposition and etching conditions and generally an incomplete oxidation of the precursor were observed. The application of QCLs for IRLAS under low pressure conditions employing the most common tuning approaches has been investigated in detail. A new method of analysing absorption features quantitatively when the rapid passage effect is present is proposed. If power saturation is negligible, integrating the undisturbed half of the line profile yields accurate number densities without calibrating the system. By means of a time resolved analysis of individual chirped QCL pulses the main reasons for increased effective laser line widths could be identified. Apart from the well-known frequency down chirp non-linear absorption phenomena and bandwidth limitations of the detection system may significantly degrade the performance and accuracy of inter pulse spectrometers. The minimum analogue bandwidth of the entire system should normally not fall below 250 MHz. QCLAS using pulsed lasers has been used for highly time resolved measurements in reactive plasmas for the first time enabling a time resolution down to about 100 ns to be achieved. A temperature increase of typically less than 50 K has been established for pulsed DC discharges containing Ar/N2 and traces of NO. The main NO production and depletion reactions have been identified from a comparison of model calculations and time resolved measurements in plasma pulses of up to 100 ms. Considerable NO struction is observed after 5 ... 10 ms due to the impact of N atoms. Finally, thermoelectrically cooled pulsed and continuous wave (cw) QCLs have been employed for high finesse cavity absorption spectroscopy in the MIR. Cavity ring down spectroscopy (CRDS) has been performed with pulsed QCLs and was found to be limited by the intrinsic frequency chirp of the laser suppressing an efficient intensity build-up inside the cavity. Consequently the accuracy and advantage of an absolute internal absorption calibration is not achievable. A room temperature cw QCL was used in a complementary cavity enhanced absorption spectroscopy (CEAS) configuration which was equipped with different cavities of up to 1.3 m length. This spectrometer yielded path lengths of up to 4 km and a noise equivalent absorption down to 4 x 10-8 cm-1Hz-1/2. The corresponding molecular concentration detection limit (e.g. for CH4, N2O and C2H2 at 1303 cm-1/7.66 Aem) was generally below 1 x 1010 cm-3 for 1 s integration times and one order of magnitude less for 30 s integration times. The main limiting factor for achieving even higher sensitivity is the residual mode noise of the cavity. Employing a 0.5 m long cavity the achieved sensitivity was good enough for the selective measurement of trace atmospheric constituents at 2.2 mbar.
Download or read book Infrared Laser Spectroscopy Systems for Measurement Applications in Industrial Environments written by Henrik Ahlberg and published by . This book was released on 1986 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Breath Analysis For Clinical Diagnosis Therapeutic Monitoring With Cd rom written by David Smith and published by World Scientific. This book was released on 2005-05-09 with total page 557 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes how the analysis of the trace gases in exhaled breath can be used for non-invasive clinical diagnosis of disease and for monitoring the effectiveness of therapy. This approach offers an important addition to the diagnostic techniques available to medicine, having the advantage that on-line breath analysis can provide information to the clinician immediately and thus facilitate rapid diagnosis and treatment. The book is a compilation of contributions to a conference held in Dornbirn, Austria, 23-26 September 2004 on various aspects of this new topic. Written by the foremost workers in the field, it will provide clinicians and others in the medical fraternity with an up-to-date summary of the status of the subject. The wide scope of the chapters ranges from descriptions of the analytical methods that are available, through the use of breath analysis in the study of physiological phenomena, to the identification of biomarkers of particular injury and disease.The proceedings have been selected for coverage in:
Download or read book Solid State Mid Infrared Laser Sources written by Irina T. Sorokina and published by Springer Science & Business Media. This book was released on 2003-07-10 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book describes the most advanced techniques for generating coherent light in the mid-infrared region of the spectrum. These techniques represent diverse areas of photonics and include heterojunction semiconductor lasers, quantum cascade lasers, tunable crystalline lasers, fiber lasers, Raman lasers, and optical parametric laser sources. Offering authoritative reviews by internationally recognized experts, the book provides a wealth of information on the essential principles and methods of the generation of coherent mid-infrared light and on some of its applications. The instructive nature of the book makes it an excellent text for physicists and practicing engineers who want to use mid-infrared laser sources in spectroscopy, medicine, remote sensing and other fields, and for researchers in various disciplines requiring a broad introduction to the subject.
Download or read book Human Respiration in Wavelenghts written by Cristina Popa and published by LAP Lambert Academic Publishing. This book was released on 2014-09-30 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present book focuses on the capabilities of laser photoacoustic spectroscopy method in high impact and new frontier of modern applications: medical diagnosis based on exhaled breath analysis with special importance on the theory, application of the simultaneous measurements of ethylene and ammonia absorptions and the study of exhaled respiration of subjects with renal failure together with breath test analysis of one prevention domain: smoking. This book consists of 4 chapters plus appendices, the first two chapters are focussed on general introduction to human breath biomarkers and the instrumental aspects of the techniques which makes it useful to readers whose main interest is photoacoustic spectroscopy and particularly breath air analysis. The technique developed in this book ensuring the advantages of health state assessment by monitoring the evolution of gaseous biomarkers in human body, impossible to achieve with current techniques. The book also, represents a potentially interesting to researchers and specialists with the application of biomedical optics domain and particularly life sciences area.
Download or read book Solid State Mid Infrared Laser Sources written by Irina T. Sorokina and published by Springer Science & Business Media. This book was released on 2003-09-04 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: This collection of authoritative reviews by leading experts provides a broad and instructive introduction to the most advanced techniques for generating coherent light in the mid-infrared region of the spectrum. With a wealth of up-to-date references – also available online.
Download or read book Semiconductor Lasers written by Alexei Baranov and published by Elsevier. This book was released on 2013-04-23 with total page 671 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor lasers have important applications in numerous fields, including engineering, biology, chemistry and medicine. They form the backbone of the optical telecommunications infrastructure supporting the internet, and are used in information storage devices, bar-code scanners, laser printers and many other everyday products. Semiconductor lasers: Fundamentals and applications is a comprehensive review of this vital technology. Part one introduces the fundamentals of semiconductor lasers, beginning with key principles before going on to discuss photonic crystal lasers, high power semiconductor lasers and laser beams, and the use of semiconductor lasers in ultrafast pulse generation. Part two then reviews applications of visible and near-infrared emitting lasers. Nonpolar and semipolar GaN-based lasers, advanced self-assembled InAs quantum dot lasers and vertical cavity surface emitting lasers are all considered, in addition to semiconductor disk and hybrid silicon lasers. Finally, applications of mid- and far-infrared emitting lasers are the focus of part three. Topics covered include GaSb-based type I quantum well diode lasers, interband cascade and terahertz quantum cascade lasers, whispering gallery mode lasers and tunable mid-infrared laser absorption spectroscopy. With its distinguished editors and international team of expert contributors, Semiconductor lasers is a valuable guide for all those involved in the design, operation and application of these important lasers, including laser and telecommunications engineers, scientists working in biology and chemistry, medical practitioners, and academics working in this field. Provides a comprehensive review of semiconductor lasers and their applications in engineering, biology, chemistry and medicine Discusses photonic crystal lasers, high power semiconductor lasers and laser beams, and the use of semiconductor lasers in ultrafast pulse generation Reviews applications of visible and near-infrared emitting lasers and mid- and far-infrared emitting lasers
Download or read book Mid infrared Optoelectronics written by Eric Tournié and published by Woodhead Publishing. This book was released on 2019-10-19 with total page 750 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mid-infrared Optoelectronics: Materials, Devices, and Applications addresses the new materials, devices and applications that have emerged over the last decade, along with exciting areas of research. Sections cover fundamentals, light sources, photodetectors, new approaches, and the application of mid-IR devices, with sections discussing LEDs, laser diodes, and quantum cascade lasers, mid-infrared optoelectronics, emerging research areas, dilute bismide and nitride alloys, Group-IV materials, gallium nitride heterostructures, and new nonlinear materials. Finally, the most relevant applications of mid-infrared devices are reviewed in industry, gas sensing, spectroscopy, and imaging. This book presents a key reference for materials scientists, engineers and professionals working in R&D in the area of semiconductors and optoelectronics. Provides a comprehensive overview of mid-infrared photodetectors and light sources and the latest materials and devices Reviews emerging areas of research in the field of mid-infrared optoelectronics, including new materials, such as wide bandgap materials, chalcogenides and new approaches, like heterogeneous integration Includes information on the most relevant applications in industry, like gas sensing, spectroscopy and imaging
