Laser-Induced Breakdown spectroscopy (LIBS) and Laser-Induced Thermal Emission (LITE) emission based laser remote sensing were investigated with the application to the remote measurements of trace chemical species. In particular, UVvisible LIBS and Mid-IR LITE systems were developed and measurements of remote targets and chemical surfaces were studied. The propagation through the atmosphere of the multi-wavelength backscattered LIBS and LITE optical spectrum with atmospheric absorption effects on the returned lidar signal was investigated. An enhanced model of the atmospheric effects on emission-based laser-remote sensing was developed and found to be consistent and in agreement with our experimental results. LITE measurements were performed which involved heating a remote hard target and recording the vibrational band emission spectra produced. Sample heating was carried out using a 1.5W cw-CO2 10.6 μm wavelength laser, and a 9W cw-diode laser operating at 809nm. The emission spectra over the wavelength range of 8 to 14 μm was observed which can be potentially used to detect and identify chemical composition of the target. LITE spectra of DMMP and DIMP (chemical agent simulants), paints, and energetic materials on various substrates were measured for the first time. A LIBS study was carried out with a 1.064 μm Nd:YAG laser (10 ns pulses, 50mJ per pulse) and remote LIBS measurements were performed for aluminum, copper, steel and plastics over the spectral range of 200 – 1000nm. LIBS measurements as a function of range were studied, and compared to a modified lidar equation suitable for emission based lidar remote sensing. A computer simulation model was developed for emission-based LIDAR remote sensing such as LIBS and LITE. This involved the development and modification of atmospheric transmission modeling programs which use the HITRAN, PNNL and other atmospheric spectral databases to model the transmission of the atmosphere over a wide range of wavelengths from the deep-UV near 200 nm to the mid-IR near 14 microns. A comparison of HITRAN simulations with the PNNL database calculated spectra was carried out and used for the first time for improvements of the HITRAN database line intensities. In addition, a Principal Component Analysis (PCA) of the LIBS and LITE lidar return signal as a function of range was performed. This PCA analysis showed, for the first time, the degradation of the chemical selectivity (i.e. identification capability) of the emission lidar system as the range was increased and the effect of atmospheric absorption spectral lines on the propagated LIBS and LITE lidar multi-wavelength spectral signal.

The absorption due to pairs of H₂ molecules is an important opacity source in the atmospheres of various types of planets and cool stars, such as late stars, low mass main sequence stars, brown dwarf stars, cool white dwarf stars, the ambers of the smaller, burnt out main sequence stars, exoplanets, etc., and therefore of special astronomical interest. Astronomers are interested in the outer planets as they still contain primordal matter. Furthermore, recent observations by the Hubble space telescope (in operation since 1990) have revealed several thousand cool white dwarf stars with temperatures of several thousand Kelvin. It is surprising that none of them has temperatures lower than roughly 4000 K. This means that the white dwarf stars have not had enough time to cool down to the temperature of the cosmic background radiation. Astrophysicists believe that this information can be used for an alternative and more accurate method of cosmochronology. However, the emission spectra of cool white dwarf stars differ significantly from the expected blackbody spectra of their cores, largely due to collision-induced absorption by collisional complexes of residual hydrogen and helium in the stellar atmospheres. In order to model the radiative processes in these atmospheres, which have temperatures of several thousand kelvin, one needs accurate knowledge of the induced dipole and potential energy surfaces of the absorbing collisional complexes, such as H₂--H₂, H₂--He, and H₂--H. These come from quantum-chemical calculations, which, for the high temperatures and high photon energies under consideration in this work, need to take into account that the H₂ bonds can be stretched or compressed far from equilibrium length. Since no laboratory measurements for these high temperatures and photon energies exist, one has to undertake \textit{ab initio} calculations which take into account the high vibrational and rotational excitation of the involved hydrogen molecules. However, before one attempts to proceed to higher temperatures and photon energies where no laboratory measurements exist it is good to check that the formalism is correct and reproduces the results at temperatures and photon energies where laboratory measurements exist, that is, at and below room temperature and for photon energies up to about 1.5 eV. In this work a formalism is developed to compute the binary collision-induced absorption of simple molecular complexes up to temperatures of thousands of kelvin and photon energies up to 2.5 eV, properly taking into account vibrational and rotational dependencies of the induced dipole and potential energy surfaces. In order to make the computational effort feasible, the isotropic potenial approximation is employed. The formalism is applied to collisional complexes of H₂--H₂, D₂--D₂, H₂--He, D₂--He, T₂--He, and H₂--H, and compared with existing laboratory measurements. / text

Le travail présenté dans ce mémoire concerne le cadre global de la connaissance de notre atmosphère. L'exploitation des spectres atmosphériques requiert une bonne connaissance des paramètres de raies des molécules qui la composent. En particulier de la vapeur qui en est l'absorbant principal. Des spectres ont été enregistrés avec le spectromètre par transformation de Fourier construit au laboratoire et ceux ci ont été traités en ajustement multi-spectres avec le logiciel MultiFiT. Ce travail se focalise sur la mesure précise des intensités de raie dans deux régions spectrales. A 10 µm, région d'intérêt atmosphérique pour l'instrument IASI, deux études sur les intensités sont présentées. Pour l'isotopologue principal de 1200 à 1400 cm-1, 300 transitions ont pu être mesurées et comparées aux données de la littérature. Le but de ce travail était de déterminer la meilleure base de données pour l'exploitation des spectres IASI. De 1000 à 2300 cm-1, les isotopologues H218O et HD18O ont été étudié à partir de spectres enrichis en 18O. Ce travail a permis de mesurer et d'attribuer un ensemble de 2500 transitions. Enfin ce mémoire propose une révision complète des intensités de la région 1.25µm, qui présentent un important problème dans les bases de données. 39 spectres ont été enregistrés pour cette région avec des échantillons d'eau naturelle. Plus de 11000 transitions ont pu être mesurées et sont comparées aux données de la littérature. Une partie de ces intensités, publiées en 2010, a été exploité par L. Tallis de l'université de Reading. Enfin ce mémoire présente le début d'une exploitation des coefficients d'élargissement obtenus dans la région de 1.25µm. / The work presented in this manuscript concern the knowledge of our atmosphere. In fact, the analysis of atmospheric spectra needs a good understanding of atmospheric molecular species. In particular the water vapor plays a special role as the first absorbent of earth's atmosphere. Spectra were recorded by Fourier transform spectrometer designed in the laboratory and lines parameters fitted with multi-spectra procedure named MultiFiT. The spectroscopic studies focus on lines intensity measurements for two different spectral ranges. The first presented is 10 µm, were two studies have been done. For the H216O isotopologue in the 1200 – 1400 cm-1 range, 300 transitions were measured and compared with literature data. The aim of this work was to determine the best spectroscopic database for IASI recording analysis. In 1000 to 2300 cm-1, H218O and HD18O isotopologue were measured with enriched 18O spectra. Over 2500 transitions were measured and assigned. Also this manuscript presents a huge work done in the 1.25µm region. This range appears in database with an important discrepancy for line intensities. 39 spectra were recorded with water vapor sample in natural abundance. Over 11000 transitions were measured and assigned, comparison to literature data are also presented. A part of this work were published in 2010 and used by L.Tallis, form University of Reading, for atmospheric application. At the end of this manuscript is presented the first comparisons with calculated data done for self broadening coefficients in the 1.25µm region.

La spectroscopie est un outil puissant et non-destructif permettant, d’après les spectres, de remonter à des grandeurs physiques importantes telles que la concentration, la température, la pression, … du gaz en question.Les travaux présentés dans ce manuscrit sont consacrés à l’analyse des spectres infrarouges et Raman à très haute résolution de l’éthylène pour des applications atmosphériques et planétologiques.Cette thèse a été effectuée au sein du Groupe de Spectrométrie Moléculaire et Atmosphérique (GSMA) de l’Université de Reims Champagne- Ardenne. En collaboration avec l’équipe (SMPCA) au sein du laboratoire Interdisciplinaire Carnot de Bourgogne (ICB) à Dijon, l’équipe (CQP) au sien du service de Chimie Quantique et Photophysique à Bruxelles, l’Instituto de Estructura de la Materia (CSIC) à Madrid et les membres de la ligne AILES du centre de rayonnement synchrotron SOLEIL à Saint-Aubin.Cette thèse est structurée en 4 chapitres. Le premier chapitre est consacré sur les généralités de la molécule étudiée. Le second chapitre présente l’aspect théorique de la spectroscopie. Le troisième chapitre portant sur l’explication du modèle théorique qui nous avons utilisé pour effectuer l’analyse et le traitement des spectres. Dans le quatrième chapitre, nous présentons les résultats de l’analyse du spectre de la molécule de l’éthylène en différentes régions spectral.Ces résultats alimenteront des bases de données internationales telles que HITRAN (L. Rothmann) et GEISA (M. Rotger et le CNES) mais aussi peuvent servir de données modèle pour la start-up AEROVIA initiée par G. Durry, directeur de notre laboratoire. Avec ces données, nous alimenterons également la base de données européenne VAMDC. / The spectroscopy is a powerful analytical technique capable of providing Important Information physical quantities such as concentration, temperature, pressure, ... and other questions about gas.The work presented in this manuscript is devoted to analysis of high resolution infrared and Raman spectroscopy of the ethylene for atmospheric, astrophysical and planetological applications.The work described in this thesis was performed within the "Groupe de Spectrométrie Moléculaire et Atmosphérique" (GSMA) in the university of Reims Champagne-Ardenne in Reims. In national collaboration with the team (SMPCA) In collaboration in the laboratory "Interdisciplinaire Carnot de Bourgogne" (ICB) in Dijon, the team (CQP) in the service de "chimie quantique et photophysique" in Brussels. l’Instituto de Estructura de la Materia (CSIC) in Madrid and the members of the line AILES of the Synchrotron SOLEIL in Saint-Aubin.The thesis is structured into 4 main chapters. The first chapter deals with the generality of molecule studied. The second chapter represents the theoretical aspects of the spectroscopy. The third chapter dealing with the explanation of the theoretical model that we used for the analysis and processing of spectra. In the fourth chapter, we present the results of the analysis of the spectrum of the molecule of ethylene in different spectral regions.These results will feed the international databases such as HITRAN (L. Rothmann) and GEISA (Mr. Rotger and CNES), and it can also serve as a data for modeling the start-up AEROVIA initiated by G. Durry, the director of the laboratory. with these data, we can also feed the European database VAMDC.

The Optical Frequency Comb Spectroscopy (OFCS) Group at the Department of Physics at Umeå University develops new techniques for extremely high sensitivity trace gas detection, non invasive temperature measurements, and other applications of OFCS. Their setup used primarily for trace gas detection contains several components that have been developed in-house, including a Fourier Transform Spectrometer (FTS) and an auto-balancing detector. This is the one used in this thesis work and it includes a high frequency data acquisition card (DAC) recording interferograms in excess of 10^7 double-precision floating point samples per sweep of the FTS's retarder. For acquisition and analysis to be possible in both directions of the retarder the interferograms needs to be analysed in a sub-second timeframe, something not possible with the present software. The aim of this thesis work has thus been to develop a system with optimized analysis implementations in MATLAB. The latter was a prerequisite from the group to ensure maintainability, as all members are well acquainted with it.Fulfilling its primary purpose MATLAB performs vector and matrix computations quite efficiently, has mostly fully mutable datatypes, and with recent just-in-time (JIT) compilation optimizations vector resizing performance has improved to what in many instances is perceived as equivalent to preallocated variables. This memory management abstraction, however, also means that explicit control of when arguments are passed by value or by reference to a function is not officially supported. The following performance ramifications naturally increase with the size of the data sets (N) passed as arguments and become quite noticeable even at moderate values of N when dealing with data visualization, a key function in system. To circumvent these problems explicit data references were implemented using some of the undocumented functions of MATLAB's libmx library together with a custom data visualization function.The main parts of the near real time interferogram analysis are resampling and a Fourier transformation, both of which had functionally complete but not optimized implementations. The minimal requirement for the reimplementation of these were simply to improve efficiency while maintaining output precision.On experimentally obtained data the new system's (DAQS) resampling implementation increased sample throughput by a factor of 19 which in the setup used corresponds to 10^8 samples per second. Memory usage was decreased by 72% or in terms of the theoretical minimum from a factor 7.1 to 2.0. Due to structural changes in the sequence of execution DAQS has no corresponding implementation of the reference FFT function as the computations performed in it have been parallelized and/or are only executed on demand, their combined CPU-time can however in a worst-case scenario reach 75% of that of the reference. The data visualization performance increase (compared to MATLAB's own, as the old system used LabVIEW) depends on the size in pixels of the surface it is visualized on and N, decreasing with the former and increasing with the latter. In the baseline case of a default surface size of 434x342 pixels and N corresponding to one full sweep of the FTS's retarder DAQS offers a 100x speed-up to the Windows 7 version of MATLAB R2014b's plot.In addition to acquiring and analyzing interferograms the primary objectives of the work included tools to configure the DAC and controlling the FTS's retarder motor, both implemented in DAQS.Secondary to the above was the implementation of acquisition and analysis for both directions of the retarder, a HITRAN reference spectra generator, and functionality to improve the user experience (UX). The first, though computation time allows for it, has not been implemented due to a delay in the DAC-driver. To provide a generic implementation of the second, the HITRAN database was converted from the text-based format it is distributed in to a MySQL database, a wrapper class providing frequency-span selection and the absorption spectra generation was developed together with a graphical front-end. Finally the improved UX functionality mainly focused on providing easy-access documentation of the properties of the DAC.In summation, though the primary objectives of optimizing the data analysis functions were reached, the end product still requires a new driver for the DAC to provide the full functionality of the reference implementation as the existing one is simply too slow. Many of DAQS' components can however be used as stand-alone classes and functions until a new driver is available. It is also worth mentioning that National Instruments (NI), the DAC vendor, has according to their technical support no plans to develop native MATLAB drivers as MathWorks will not sell them licenses.

The design of a photonics-based multi-gas sensor is presented. Absorption spectroscopy theory has been analyzed to derive key requirements for effective gas concentration measurements. HITRAN spectral analyses have determined appropriate ranges for single and multi-gas sensing. A discussion of two setups (large-scale setup and portable prototype) outlines relevant results for the development of innovative data processing algorithms (floating-point technique (FPT)). Eight absorption lines were experimentally detected (761 nm range), facilitating the recognition of oxygen spectra with surety. The FPT was used to measure oxygen concentration with an approx. 2.5% error when scanning one absorption line. Strategies to reduce the error to below 0.1% and to improve the prototype are presented. The sensor is expected to operate in an inhomogeneous network. The network utilizes different sensors capable of cross-using information to achieve high reliability and accuracy, in order to predict, prevent, and recognize man-made and natural threats.

The design of a photonics-based multi-gas sensor is presented. Absorption spectroscopy theory has been analyzed to derive key requirements for effective gas concentration measurements. HITRAN spectral analyses have determined appropriate ranges for single and multi-gas sensing. A discussion of two setups (large-scale setup and portable prototype) outlines relevant results for the development of innovative data processing algorithms (floating-point technique (FPT)). Eight absorption lines were experimentally detected (761 nm range), facilitating the recognition of oxygen spectra with surety. The FPT was used to measure oxygen concentration with an approx. 2.5% error when scanning one absorption line. Strategies to reduce the error to below 0.1% and to improve the prototype are presented. The sensor is expected to operate in an inhomogeneous network. The network utilizes different sensors capable of cross-using information to achieve high reliability and accuracy, in order to predict, prevent, and recognize man-made and natural threats.

The aim of this diploma thesis is to get acquainted with modern technological elements currently used in shell-and-tube heat exchanger in the shell-side and tube-side, thermal-hydraulic calculation of selected elements and comparison of thermal-hydraulic properties with classically used competing technological elements. The work deals mainly with EM baffle in the tube-side and tube inserts like the twisted tape type (and its modifications) and coiled wire in the tube-side. The theoretical part is focused on acquaintance with classical technological elements in shell-and-tube heat exchanger and with basic thermal-hydraulic calculations, practical part then on acquaintance with modern elements and thermal-hydraulic calculation of selected elements. These calculations are then compared with the results of the thermo-hydraulic calculation of similar elements.