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- Title
- PLASMA TEMPERATURE MEASUREMENTS IN THE CONTEXT OF SPECTRAL INTERFERENCE.
- Creator
-
Seesahai, Brandon, Baudelet, Matthieu, University of Central Florida
- Abstract / Description
-
The path explored in this thesis is testing a plasma temperature measurement approach that accounts for interference in a spectrum. The Atomic Emission Spectroscopy (AES) technique used is called Laser Induced Breakdown Spectroscopy (LIBS) and involves focusing a laser pulse to a high irradiance onto a sample to induced a plasma. Spectrally analyzing the plasma light provides a "finger print" or spectrum of the sample. Unfortunately, spectral line broadening is a type of interference...
Show moreThe path explored in this thesis is testing a plasma temperature measurement approach that accounts for interference in a spectrum. The Atomic Emission Spectroscopy (AES) technique used is called Laser Induced Breakdown Spectroscopy (LIBS) and involves focusing a laser pulse to a high irradiance onto a sample to induced a plasma. Spectrally analyzing the plasma light provides a "finger print" or spectrum of the sample. Unfortunately, spectral line broadening is a type of interference encountered in a LIBS spectrum because it blends possible ionic or atomic transitions that occur in plasma. To make use of the information or transitions not resolved in a LIBS spectrum, a plasma temperature method is developed. The basic theory of a LIBS plasma, broadening mechanisms, thermal equilibrium and distribution laws, and plasma temperature methods are discussed as background support for the plasma temperature method tested in this thesis. In summary, the plasma temperature method analyzes the Full Width at Half the Maximum (FWHM) of each spectral line for transitions provided from a database and uses them for temperature measurements. The first implementation of the temperature method was for simulated spectra and the results are compared to other conventional temperature measurement techniques. The temporal evolution of experimental spectra are also taken as a function of time to observe if the newly developed temperature technique can perform temporal measurements. Lastly, the temperature method is tested for a simulated, single element spectrum when considering interferences from all the elements provided in an atomic database. From stimulated and experimental spectra analysis to a global database consideration, the advantages and disadvantages of the temperature method are discussed.
Show less - Date Issued
- 2016
- Identifier
- CFH2000140, ucf:46057
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000140
- Title
- Qualitative and Quantitative Elemental Composition Analysis of the Surrounding Pollen Coating via ICP-MS.
- Creator
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Voyer, Brandy, Baudelet, Matthieu, Rex, Matthew, Sigman, Michael, University of Central Florida
- Abstract / Description
-
Pollen evidence has proven to be a powerful forensic tool to trace a suspect or item to a victim or a crime scene. This is possible because it is microscopic, abundant in nature, resistant to degradation and decay; it presents dispersal patterns that can be used to generate a 'fingerprint' within specific areas, and has illustrated a unique morphology that can be used to classify species. While the pollen grain morphology has been extensively used to characterize the specific species, not...
Show morePollen evidence has proven to be a powerful forensic tool to trace a suspect or item to a victim or a crime scene. This is possible because it is microscopic, abundant in nature, resistant to degradation and decay; it presents dispersal patterns that can be used to generate a 'fingerprint' within specific areas, and has illustrated a unique morphology that can be used to classify species. While the pollen grain morphology has been extensively used to characterize the specific species, not much has been investigated as pertains to the coating that surrounds the pollen grain aside from it being categorized as waste. This Master thesis focuses on the qualitative and quantitative determination of the elemental composition of this coating surrounding pollen via Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Two methodologies for sample preparation were compared: a complete digestion and analysis of (i) the entire pollen and (ii) the surrounding pollen coating alone removed from the pollen grain by Soxhlet extraction in ethanol. The goal was to discern the elemental composition of the coating and its specific elemental composition in comparison with the whole pollen grain. The results of both F-test and T-test performed for three pollen species indicated that, of the 19 elements investigated, B, Mg, Mn, K, Ti, and Cs resulted in significant differences between the whole grain and the coating alone; while Se, V, Pb, Cr, Al, and Zn can be recognized as being characteristic of the coating surrounding the pollen grain.
Show less - Date Issued
- 2018
- Identifier
- CFE0007261, ucf:52189
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007261
- Title
- Methodological Improvements in the mRNA Profiling Assays for Incorporation into DNA Casework Workflows.
- Creator
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Volk, Paris, Ballantyne, John, Gerasimova, Yulia, Baudelet, Matthieu, University of Central Florida
- Abstract / Description
-
Currently, DNA profiling is the gold standard to identify an individual. However, determining body fluid origin is important in criminal investigations, offering additional information surrounding the circumstances of a crime. However, crime labs can only definitively identify blood and semen and presumptively saliva using techniques that consume time and sample and do not simultaneously identify all forensically relevant body fluids. This causes many crime labs to want to bypass body fluid...
Show moreCurrently, DNA profiling is the gold standard to identify an individual. However, determining body fluid origin is important in criminal investigations, offering additional information surrounding the circumstances of a crime. However, crime labs can only definitively identify blood and semen and presumptively saliva using techniques that consume time and sample and do not simultaneously identify all forensically relevant body fluids. This causes many crime labs to want to bypass body fluid identification altogether. Therefore, advances into more definitive molecular-based body fluid methods are necessary. One such technique is mRNA profiling because it provides a highly sensitive and specific approach to definitively identifying all relevant body fluids in parallel. Although advancements have been made, improvements to mRNA profiling methodologies still need to be researched such as 1) possible mRNA recovery from established DNA workflows and 2) possible integration of mRNA profiling into an upfront male DNA screening assay for triaging sexual-assault evidence likely to contain male DNA and reduce/eliminate a significant bottleneck in the standard DNA workflow of microscopic sperm identification. This study was designed to address these two issues by evaluating a novel way to recover RNA, for body fluid identification, from the waste fractions of a PrepFiler(TM) DNA extraction, and from the DNA extracts directly. Next, this study aimed to provide a relatively quick molecular-based approach for screening sexual-assault evidence. It involves extraction of RNA using the Dynabeads(TM) mRNA DIRECT(TM) Kit, while saving the extraction waste fractions for downstream male-DNA quantitation and STR profiling. The RNA is then used in a rapid and sensitive 1-step combined reverse transcription-HRM assay to positively detect the presence of sperm. Both non-conventional co-extraction methods successfully addressed current body fluid identification challenges and allowed for easy integration into existing workflows when single sourced, mixture and mock casework samples were analyzed.
Show less - Date Issued
- 2019
- Identifier
- CFE0007551, ucf:52627
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007551
- Title
- Filament Wavefront Evolution.
- Creator
-
Thul, Daniel, Richardson, Martin, Shah, Lawrence, Baudelet, Matthieu, University of Central Florida
- Abstract / Description
-
Filamentation is a complex process that gives rise to many nonlinear interactions. However, the fundamentals of filament formation and propagation can be explained in terms of two dominant mechanisms: Kerr self-focusing and plasma defocusing. The first to occur, self-focusing, is responsible for an increase in irradiance through beam collapse. This process requires sufficient initial peak power, on the order of gigawatts for near infrared beams in air. Plasma defocusing then arrests the...
Show moreFilamentation is a complex process that gives rise to many nonlinear interactions. However, the fundamentals of filament formation and propagation can be explained in terms of two dominant mechanisms: Kerr self-focusing and plasma defocusing. The first to occur, self-focusing, is responsible for an increase in irradiance through beam collapse. This process requires sufficient initial peak power, on the order of gigawatts for near infrared beams in air. Plasma defocusing then arrests the collapse process once the irradiance reaches the ionization threshold of the medium. These two pro-cesses balance each other in an extended plasma channel known as a filament. A beam's collapse behavior is strongly influenced by the initial beam conditions, espe-cially in applications that require power scaling to terawatt levels where the Kerr effect is more pronounced. Therefore, understanding and controlling the collapse process is essential in this regime. For this reason, an exploration of the wavefront evolution of filamenting beams is of great interest and the topic of this thesis, which has three parts. First, it reviews the filamentation process and describes characteristics of filaments. Next, experimental measurements of the wavefronts of filamenting beams are given in two separate regimes. The first regime is the Kerr self-focusing that takes place before beam collapse is arrested. This data is then contrasted with wavefront measurements within a filament after collapse has occurred.
Show less - Date Issued
- 2017
- Identifier
- CFE0006808, ucf:51804
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006808
- Title
- Enhanced Ablation by Femtosecond and Nanoseond Laser Pulses.
- Creator
-
Kerrigan, Haley, Richardson, Martin, Baudelet, Matthieu, Shivamoggi, Bhimsen, University of Central Florida
- Abstract / Description
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Laser ablation of GaAs by a combination of femtosecond and nanosecond pulses is investigated as a means of enhancing material removal by a femtosecond pulse in the filamentation intensity regime. We demonstrate for the first time increased ablation of GaAs by ultrafast laser pulse plasmas augmented by nanosecond pulse radiation from a secondary laser. Material removal during laser ablation is a complex process that occurs via multiple mechanisms over several timescales. Due to different pulse...
Show moreLaser ablation of GaAs by a combination of femtosecond and nanosecond pulses is investigated as a means of enhancing material removal by a femtosecond pulse in the filamentation intensity regime. We demonstrate for the first time increased ablation of GaAs by ultrafast laser pulse plasmas augmented by nanosecond pulse radiation from a secondary laser. Material removal during laser ablation is a complex process that occurs via multiple mechanisms over several timescales. Due to different pulse durations, ablation by femtosecond and nanosecond pulses are dominated by different mechanisms. Ablation can be enhanced by optimally combining a femtosecond and nanosecond pulse in time. In this work, the craters generated by combinations of pulses are investigated for inter-pulse delays ranging from -50ns to +1?s, with the fs pulse preceding the ns pulse corresponding to a positive delay. The Ti:Sapph Multi-Terawatt Femtosecond Laser (MTFL) in the Laser Plasma Laboratory (LPL) provides 50fs pulses at 800nm with intensities of 1014W/cm^2 at the sample. An Nd:YAG laser (Quantel CFR200) provides 8ns pulses at 1064nm with intensities of 109W/cm^2. Crater profilometry with white-light interferometry and optical microscopy determine the structure and surface features of the craters and the volume of material removed. Ultrafast shadowgraphy of the ejected plasma provides insight to the dual-pulse ablation dynamics. Sedov-Taylor analysis of the generated shockwave reveals the energy coupled to the sample or preceding plasma. It was found that inter-pulse delays between +40 and +200ns yielded craters 2.5x greater in volume than that of the femtosecond pulse alone, with a maximum enhancement of 2.7x at +100ns. Shadowgraphy of -40 to +40ns delays revealed that enhancement occurs when the nanosecond pulse couples to plasma generated by the fs pulse. This work provides a possible means of enhancing ablation by femtosecond filaments, which propagate long distances with clamped intensity, advancing long-range stand-off ablation
Show less - Date Issued
- 2017
- Identifier
- CFE0006889, ucf:51734
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006889
- Title
- An Assessment of Trace Elements Distribution in Teeth Utilizing a Sample Group from Postclassic Lamanai: The Application of LA-ICP-MS in Bioarchaeology and Forensics.
- Creator
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Hawkins, Michelle, Schultz, John, Williams, Lana, Baudelet, Matthieu, University of Central Florida
- Abstract / Description
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Trace element analysis of skeletal remains and teeth is a common research technique in biological and forensic anthropology. In particular, LA-ICP-MS has become a widely-accepted tool for analyzing and mapping the distribution of trace elements in teeth. Investigation into the relative spectral intensities and spatial distribution of thirteen trace isotopes (13C, 24Mg, 27Al, 31P, 44Ca, 47Ti, 52Cr, 55Mn, 56Fe, 66Zn, 88Sr, 138Ba, 208Pb) within teeth was undertaken using LA-ICP-MS. The total...
Show moreTrace element analysis of skeletal remains and teeth is a common research technique in biological and forensic anthropology. In particular, LA-ICP-MS has become a widely-accepted tool for analyzing and mapping the distribution of trace elements in teeth. Investigation into the relative spectral intensities and spatial distribution of thirteen trace isotopes (13C, 24Mg, 27Al, 31P, 44Ca, 47Ti, 52Cr, 55Mn, 56Fe, 66Zn, 88Sr, 138Ba, 208Pb) within teeth was undertaken using LA-ICP-MS. The total archaeological sample of teeth (N=26) was comprised of four tooth types (UCI, ULI, UPM1, and UPM2) and 18 individuals from a Postclassic Lamanai site. In preparation for analysis, teeth sectioned down the center using a low-speed saw. Maps were created using the laser ablation system and MATLAB(&)#174; software. The frequency of each isotope detected at low, moderate, and high intensities at each of the six defined tooth locations was calculated. The inner dentine and the outer root border were the two areas that most commonly exhibited the highest intensities of isotopes. Detection of major structural isotopes (44Ca and 31P) was similar in both spatial locations and relative intensity across all teeth. In comparison, detection of more minor isotopes, while similar in spatial locations across all teeth, varied in relative intensity per individual sample. The frequency that each isotope was detected also varied by tooth type. These findings demonstrate the disparities between different types of dental tissue for retaining trace elements and serve to illuminate possible sources of external exposure and internal bioavailability influencing interindividual variation within the Lamanai sample population. Variation in isotope frequency based on tooth type may be due to developmental properties and/or changes in diet during early life. Ultimately, teeth act as storehouses of trace elements, and maps of isotopic distribution in teeth help reveal how individuals are influenced by both biological processes and cultural activities.
Show less - Date Issued
- 2017
- Identifier
- CFE0006881, ucf:51722
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006881
- Title
- Coupling of Laser Beams for Filament Propagation.
- Creator
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Kepler, Daniel, Richardson, Martin, Baudelet, Matthieu, Christodoulides, Demetrios, University of Central Florida
- Abstract / Description
-
Laser filamentation is a nonlinear process involving high-energy, ultrashort pulses that create narrow, non-diffracting structures over many times the Raleigh length. While many of the characteristics of filaments can vary greatly depending on the physical parameters used to create them, they share several defining features: a high intensity core, a lower intensity cladding of photons that serves as an energy reservoir to the core, and spectral broadening into a supercontinuum. While there...
Show moreLaser filamentation is a nonlinear process involving high-energy, ultrashort pulses that create narrow, non-diffracting structures over many times the Raleigh length. While many of the characteristics of filaments can vary greatly depending on the physical parameters used to create them, they share several defining features: a high intensity core, a lower intensity cladding of photons that serves as an energy reservoir to the core, and spectral broadening into a supercontinuum. While there have been many studies on the creation and control of multiple filaments from one laser pulse and a few studies on the interaction of two single filaments, many fundamental questions concerning the nature of this interaction still exist.This thesis seeks to explore the correlation between ultrashort pulses involving spatial separation, temporal delay, and relative degree of polarization using an interferometric approach. Evaluating the beam profiles and spectrum that result from varying those parameters.
Show less - Date Issued
- 2016
- Identifier
- CFE0006531, ucf:51374
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006531
- Title
- LASER FILAMENT INTERACTION WITH AEROSOLS AND CLOUDS.
- Creator
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Jeon, Cheonha, Richardson, Martin, Vanstryland, Eric, Baudelet, Matthieu, Sigman, Michael, University of Central Florida
- Abstract / Description
-
A high powered ultrashort laser pulse can propagate as a diffraction-free self-channeled structure called a filament, created by a combination of nonlinear processes. With its ability to convey extremely high intensity beams to distant targets, many applications such as remote sensing, cloud seeding, and discharge guiding are potentially possible. However, one of the main challenges of outdoor field applications is the laser propagation through the atmosphere where pressure fluctuations and...
Show moreA high powered ultrashort laser pulse can propagate as a diffraction-free self-channeled structure called a filament, created by a combination of nonlinear processes. With its ability to convey extremely high intensity beams to distant targets, many applications such as remote sensing, cloud seeding, and discharge guiding are potentially possible. However, one of the main challenges of outdoor field applications is the laser propagation through the atmosphere where pressure fluctuations and concentrations of aerosols may be present. The rationale behind the work presented in this dissertation is to evaluate the robustness of the filamentation, measure the interaction losses as well as understanding the modifications to (i) filament length (ii) supercontinuum generation, and (iii) the beam profile along propagation through perturbed media.Detailed studies of the interaction of a single filament with a single water droplet are presented. In addition, preliminary results on filament propagation through a cloud of aerosols are discussed. The effect of pressure on the beam profile along propagation and on the supercontinuum generated by the filament is studied. This document provides valuable insight into the complex nonlinear processes affecting the formation, propagation and post propagation of filaments under adverse atmospheric conditions.
Show less - Date Issued
- 2016
- Identifier
- CFE0006530, ucf:51368
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006530
- Title
- Femtosecond Filament Interaction as a Probe for Molecular Alignment.
- Creator
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McKee, Erik, Richardson, Martin, Baudelet, Matthieu, Chang, Zenghu, University of Central Florida
- Abstract / Description
-
Femtosecond laser filamentation is a highly nonlinear propagation mode. When a laser pulse propagates with a peak power exceeding a critical value Pcr (5 GW at 800 nm in air), the Kerr effect tends to collapse the beam until the intensity is high enough to ionize the medium, giving rise to plasma defocusing. A dynamic competition between these two effects takes place leaving a thin and weakly ionized plasma channel in the trail of the pulse. When an ultrafast laser pulse interacts with...
Show moreFemtosecond laser filamentation is a highly nonlinear propagation mode. When a laser pulse propagates with a peak power exceeding a critical value Pcr (5 GW at 800 nm in air), the Kerr effect tends to collapse the beam until the intensity is high enough to ionize the medium, giving rise to plasma defocusing. A dynamic competition between these two effects takes place leaving a thin and weakly ionized plasma channel in the trail of the pulse. When an ultrafast laser pulse interacts with molecules, it will align them, spinning them about their axis of polarization. As the quantum rotational wave packet relaxes, the molecules will experience periodic field-free alignment. Recent work has demonstrated the effect of molecular alignment on laser filamentation of ultra-short pulses. Revival of the molecular alignment can modify filamentation parameters as it can locally modify the refractive index and the ionization rate. In this thesis, we demonstrate with simulations and experiments that these changes in the filament parameters (collapse distance and filament plasma length) can be used to probe molecular alignment in CO2.
Show less - Date Issued
- 2013
- Identifier
- CFE0005033, ucf:50000
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005033
- Title
- Investigating The Late Woodland Climate Of Old Tampa Bay, Florida.
- Creator
-
Rogers, Jaime, Barber, Sarah, Williams, Lana, Baudelet, Matthieu, Starbuck, John, University of Central Florida
- Abstract / Description
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Tampa Bay and the broader Central Gulf Coast region of Florida bear evidence of site reduction and population decline during the onset of the Late Woodland period (AD 500-1000). Concomitantly, Weeden Island culture flourished to the north, while climatic instability loomed to the south. It is unclear if the site abandonments in the area between the two are related to social or cultural change, an unstable climate, or a combination thereof. Interdisciplinary research has provided evidence for...
Show moreTampa Bay and the broader Central Gulf Coast region of Florida bear evidence of site reduction and population decline during the onset of the Late Woodland period (AD 500-1000). Concomitantly, Weeden Island culture flourished to the north, while climatic instability loomed to the south. It is unclear if the site abandonments in the area between the two are related to social or cultural change, an unstable climate, or a combination thereof. Interdisciplinary research has provided evidence for climate change and sea level regression during the sixth and seventh centuries in Southwest Florida, but these variables have yet to be investigated in Tampa Bay. This study implements a multi-scalar sclerochronological analysis to better understand how the climate of Tampa Bay has changed through time. Analyses of low-resolution stable isotopes (13C and 18O) paired with high-resolution trace elements (Mg, Na, Li, Sr) from 50 eastern oyster (Crassostrea virginica) specimens supports climatic instability during the Late Woodland period in Tampa Bay.
Show less - Date Issued
- 2019
- Identifier
- CFE0007902, ucf:52749
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007902
- Title
- Preliminary Investigation into Biological Sex Estimation Using Trace Element Analysis in Human Hair.
- Creator
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Woltering, Abigail, Dupras, Tosha, Williams, Lana, Schultz, John, Starbuck, John, Baudelet, Matthieu, University of Central Florida
- Abstract / Description
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In forensic anthropology the estimation of biological sex of unidentified human remains is critical, as it essentially halves the number of potential identities. Sex estimation is also important in bioarchaeology, because the creation of the biological profile is critical to the interpretation of different sociocultural aspects of past populations. Furthermore, certain aspects of the biological profile are sex specific, so it is important to be able to accurately determine biological sex ...
Show moreIn forensic anthropology the estimation of biological sex of unidentified human remains is critical, as it essentially halves the number of potential identities. Sex estimation is also important in bioarchaeology, because the creation of the biological profile is critical to the interpretation of different sociocultural aspects of past populations. Furthermore, certain aspects of the biological profile are sex specific, so it is important to be able to accurately determine biological sex (France 1998). Typically, biological sex is estimated by assessing sexually dimorphic differences within the pelvis and skull. However, because sexually dimorphic differences arise during puberty it is difficult, and oftentimes impossible, to use these traditional techniques on juveniles. Recently, human hair has gained prominence in anthropological research. This is particularly evident in bioarchaeology, where hair can be used to discern information concerning health, toxicology, culture, and diet of past populations. This study focuses on the relationship between the content of trace elements in hair and biological sex to determine if biological sex can be assessed from the content of trace elements in human head hair. Hair was collected from three human sample groups: modern living individuals, modern cadavers, and archaeological remains. Data on trace elements was collected using laser-induced breakdown spectroscopy (LIBS). The statistical relationship between the content of trace elements and sex was then analyzed using a multivariate analysis of variance (MANOVA), post-hoc analysis of variance (ANOVAs), and stepwise binary logistic regression. The MANOVA revealed a statistically significant multivariate main effect for sample group using mean values (p-value (<) 0.0001) and mean variance values (MVs) (p-value = 0.018). Given the significant results of the MANOVA test, the univariate main effects were examined with post-hoc ANOVA tests. Significant univariate main effects were obtained for mean values for C/Mg (p-value (<) 0.0001), C/Fe (p-value (<) 0.0001), C/Ca (p-value (<) 0.0001), and C/Sr (p-value (<) 0.0001). Significant univariate main effects were obtained for MVs for C/Mg (p-value = 0.016), C/Fe (p-value = 0.010), and C/Sr (p-value = 0.042). These preliminary results demonstrate that biological sex of humans can be accurately estimated through trace elemental analysis approximately 85% of the time in living samples, and 79% of the time overall. The results also demonstrate the viability of this technique for sex estimation in juvenile remains with approximately 83% success in predicting juvenile biological sex. This sets the stage establishing trace elemental analysis of hair as a technique for estimating biological sex which is critical to forensic individuation and identification as well as further contextualization of archaeological remains.
Show less - Date Issued
- 2016
- Identifier
- CFE0006705, ucf:51928
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006705
- Title
- Design and Engineering Criteria for Optical Parametric Chirped Pulse Amplifier Systems.
- Creator
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Bodnar, Nathan, Richardson, Martin, Delfyett, Peter, Likamwa, Patrick, Baudelet, Matthieu, Shah, Lawrence, University of Central Florida
- Abstract / Description
-
The generation of a quasi-single-cycle laser light pulse is a goal in many laser applications experiments. Some involve in High Harmonic Generation (HHG) and Attosecond Sciences. The demand for ultrafast laser facilities has grown; the techniques and availability of materials have changed; thereby posing new design challenges in building Optical Parametric Chirped Pulse Amplification (OPCPA) laser facilities. The concepts and challenges are discussed in detail in the development of two laser...
Show moreThe generation of a quasi-single-cycle laser light pulse is a goal in many laser applications experiments. Some involve in High Harmonic Generation (HHG) and Attosecond Sciences. The demand for ultrafast laser facilities has grown; the techniques and availability of materials have changed; thereby posing new design challenges in building Optical Parametric Chirped Pulse Amplification (OPCPA) laser facilities. The concepts and challenges are discussed in detail in the development of two laser systems within the Laser Plasma Laboratory, HERACLES and PhaSTHEUS. This dissertation also gives insight to the challenges that are encountered in other cutting edge OPCPA laser facilities. An overview of the design challenges that need to be addressed in any OPCPA laser facility either high energy or high average power that is suitable for high intensity laser physics is discussed in this dissertation.
Show less - Date Issued
- 2018
- Identifier
- CFE0007158, ucf:52300
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007158
- Title
- Quantitative Line Assignment in Optical Emission Spectroscopy.
- Creator
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Chappell, Jessica, Baudelet, Matthieu, Hernandez, Florencio, Campiglia, Andres, Ni, Liqiang, Sigman, Michael, University of Central Florida
- Abstract / Description
-
Quantitative elemental analysis using Optical Emission Spectroscopy (OES) starts with a high level of confidence in spectral line assignment from reference databases. Spectral interferences caused by instrumental and line broadening decrease the resolution of OES spectra creating uncertainty in the elemental profile of a sample for the first time. An approach has been developed to quantify spectral interferences for individual line assignment in OES. The algorithm calculates a statistical...
Show moreQuantitative elemental analysis using Optical Emission Spectroscopy (OES) starts with a high level of confidence in spectral line assignment from reference databases. Spectral interferences caused by instrumental and line broadening decrease the resolution of OES spectra creating uncertainty in the elemental profile of a sample for the first time. An approach has been developed to quantify spectral interferences for individual line assignment in OES. The algorithm calculates a statistical interference factor (SIF) that combines a physical understanding of plasma emission with a Bayesian analysis of the OES spectrum. It can be used on a single optical spectrum and still address individual lines. Contrary to current methods, quantification of the uncertainty in elemental profiles of OES, leads to more accurate results, higher reliability and validation of the method. The SIF algorithm was evaluated for Laser-Induced Breakdown Spectroscopy (LIBS) on samples with increasing complexity: from silicon to nickel spiked alumina to NIST standards (600 glass series and nickel-chromium alloy). The influence of the user's knowledge of the sample composition was studied and showed that for the majority of spectral lines this information is not changing the line assignment for simple compositions. Nonetheless, the amount of interference could change with this information, as expected. Variance of the SIF results for NIST glass standard was evaluated by the chi-square hypothesis test of variance showing that the results of the SIF algorithm are very reproducible.
Show less - Date Issued
- 2018
- Identifier
- CFE0007564, ucf:52575
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007564
- Title
- Precision Metrology of Laser Plasmas in the XUV Band.
- Creator
-
Szilagyi, John, Richardson, Martin, Sundaram, Kalpathy, Abdolvand, Reza, Baudelet, Matthieu, Shivamoggi, Bhimsen, University of Central Florida
- Abstract / Description
-
The XUV band, a region of light spanning the wavelength range of 5 - 200 nm, is located between the Ultraviolet and X-ray regions of the electromagnetic spectrum. It is further divided into a 100 - 200 nm region called the Vacuum Ultraviolet (VUV), and a 5 (-) 100 nm region called the Extreme Ultraviolet (EUV). Applications of this light have been slow to develop due to the lack of suitable sources, efficient optics, and sensitive detectors. Recently, many industries such as the semiconductor...
Show moreThe XUV band, a region of light spanning the wavelength range of 5 - 200 nm, is located between the Ultraviolet and X-ray regions of the electromagnetic spectrum. It is further divided into a 100 - 200 nm region called the Vacuum Ultraviolet (VUV), and a 5 (-) 100 nm region called the Extreme Ultraviolet (EUV). Applications of this light have been slow to develop due to the lack of suitable sources, efficient optics, and sensitive detectors. Recently, many industries such as the semiconductor manufacturing industry, medical surgery, micromachining, microscopy, and spectroscopy have begun to benefit from the short wavelengths and the high photon energies of this light. At present, the semiconductor chip industry is the primary reason for the investment in, and development of, XUV sources, optics, and detectors. The demand for high power EUV light sources at 13.5 nm wavelength is driven by the development of the next generation of semiconductor lithography tools. The development of these tools enables the continued reduction in size, and the increase in transistor density of semiconductor devices on a single chip. Further development and investigation of laser produced plasma EUV light sources is necessary to increase the average optical power and reliability. This will lead to an increase in the speed of EUV lithographic processes, which are necessary for future generations of advanced chip design, and high volume semiconductor manufacturing. Micromachining, lithography, and microscopy benefit from improvements in resolution due to the shorter wavelengths of light in the VUV band. In order to provide adequate illumination for these applications, sources are required which are brighter and have higher average power. Laser produced plasma (LPP) VUV light sources are used extensively for lithography and defect detection in semiconductor manufacturing. Reductions in the wavelength and increases in the average power will increase the rate and yield of chip manufacture, as well as reduce the costs of semiconductor manufacture.The work presented in this thesis, describes the development of two laser plasma source facilities in the Laser Plasma Laboratory at UCF, which were designed to investigate EUV and VUV laser plasma sources. The HP-EUV-Facility was developed to optimize and demonstrate a high power 13.5 nm EUV LPP source. This facility provides high resolution spectroscopy across 10.5 - 20 nm, and absolute energy measurement of 13.5 nm +/- 2% in 2? sr. The VUV-MS-Facility was developed to investigate VUV emission characteristics of laser plasmas of various target geometries and chemistries. This facility provides absolute calibrated emission spectra for the 124 - 250 nm wavelength range, in addition to, at wavelength plasma imaging. Calibrated emission spectra, in-band power, and conversion efficiency are presented in this work for gas targets of Argon, Krypton, and Xenon and solid targets of Silicon, Copper, Molybdenum, Indium, Tantalum, Tin, and Zinc, across the laser intensity range of 8.0x10^6 (-) 3.2x10^12 W/cm2.
Show less - Date Issued
- 2017
- Identifier
- CFE0006805, ucf:51793
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006805
- Title
- Quantification of non-stoichiometry and impurities in transparent YAG ceramics by laser-induced breakdown spectroscopy (LIBS).
- Creator
-
Pandey, Sudeep, Gaume, Romain, Coffey, Kevin, Klemm, Richard, Baudelet, Matthieu, Curtarolo, Stefano, University of Central Florida
- Abstract / Description
-
Transparent ceramics are an important class of optical materials with applications in street-lighting, high-strength windows, electro- and magneto-optical isolators, high-power laser gain media and nuclear radiation detectors. Compared to single-crystal growth, ceramic processing enables size scalability, near net-shape forming and prevents issues associated with dopant segregation and inhomogeneity, such as stress-induced birefringence and wavefront distortions. The fabrication of high...
Show moreTransparent ceramics are an important class of optical materials with applications in street-lighting, high-strength windows, electro- and magneto-optical isolators, high-power laser gain media and nuclear radiation detectors. Compared to single-crystal growth, ceramic processing enables size scalability, near net-shape forming and prevents issues associated with dopant segregation and inhomogeneity, such as stress-induced birefringence and wavefront distortions. The fabrication of high optical grade ceramics by route of powder sintering, relies on a controlled set of techniques preventing the formation of scattering centers (pores and secondary phases) and harmful point defects (color centers, charge-carrier trapping sites). This thesis work investigates a novel approach in assisting the fabrication of yttrium aluminum garnet (YAG, Y3Al5O12) transparent ceramics, an important laser material, and minimizing the presence of these defects. As a line compound in the Al2O3-Y2O3 phase diagram, YAG has little tolerance for excess of either yttrium or aluminum oxides. What is more, the estimated compositional range of the garnet phase, (5/3-0.03)(<)Al/Y(<)(5/3+0.008), which is at the root of fabrication inconsistencies, challenges the sensitivity of most analytical techniques. We have evaluated the use of laser-induced breakdown spectroscopy (LIBS), a rapid, cost effective, non-destructive, and versatile technique, in the determination of stoichiometry and impurities at the various stages of the ceramic fabrication, i.e. in powders, green and sintered bodies. It was found that enough sensitivity and accuracy can be achieved on a custom-built system to discern 0.3 mole percent in the Al/Y ratio. To understand the influence of the plasma temperature on the ratio of the atomic emission lines of Al and Y species, simulations of YAG-based laser-induced plasmas were performed. The results have guided our experimental protocol by showing that above 12000 K, the Al/Y intensity ratio and thus the sensitivity of the measurement increases sharply with plasma temperature. In addition, we show that LIBS can be used to monitor the concentrations of unintentional trace impurities along those of sintering additives (SiO2) customarily used for the removal of porosity during firing. Hence, we reveal, for example, that less than 30% of SiO2 remains in the final ceramic due to evaporation during high temperature sintering. This work not only extends the range of capabilities of LIBS by showing how highly sensitive quantification of major elements can be performed in insulating materials, but also provides a new set of tools for estimating the range of solid-state solutions in advanced materials and understanding the densification of ceramics. We foresee that such capability will be invaluable for quality control purposes and in areas where fine and reproducible compositional tuning (defect engineering) is needed.
Show less - Date Issued
- 2017
- Identifier
- CFE0006774, ucf:51855
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006774
- Title
- The Characterization of Condom Lubricants and Personal Hygiene Products using DART-TOFMS and GC- MS and The Investigation of Gold Nanoparticle Behavior in Water and the Interaction with Blood Serum Proteins.
- Creator
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Moustafa, Yasmine, Huo, Qun, Bridge, Candice, Sigman, Michael, Baudelet, Matthieu, Popolan-Vaida, Denisia, Ni, Liqiang, University of Central Florida
- Abstract / Description
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This dissertation is divided into two independent research projects. First, condom lubricants, sexual lubricants, and personal hygiene products (PHPs) were studied using direct analysis in real time-time-of-flight-mass spectrometry (DART-TOFMS) and gas chromatography-mass spectrometry (GC-MS). The purpose addressed the concern of perpetrators resorting to new tactics, i.e. using condoms to remove seminal fluid that could provide a DNA link to a suspect, leading to the need of the...
Show moreThis dissertation is divided into two independent research projects. First, condom lubricants, sexual lubricants, and personal hygiene products (PHPs) were studied using direct analysis in real time-time-of-flight-mass spectrometry (DART-TOFMS) and gas chromatography-mass spectrometry (GC-MS). The purpose addressed the concern of perpetrators resorting to new tactics, i.e. using condoms to remove seminal fluid that could provide a DNA link to a suspect, leading to the need of the consideration of condom lubricants as pieces of sexual assault evidence. Due to condom lubricants having a chemical composition resembling PHPs, the investigation of both sample groups was analyzed to prevent false positives. Although past research has focused on the identification of major lubricant groups and additives, the discernment between such samples is insufficient. The discriminatory capability and rapid analysis of samples using DART-TOFMS was illustrated through resolution among the sample groups and higher classification rates. Here, lubricant analysis was introduced as a viable source of evidence, with a scheme detailing their discrimination from common hygiene products using DART-TOFMS as a robust tool for the analysis of sexual assault evidence. Second, gold nanoparticles (AuNPs) were characterized using dynamic light scattering (DLS), Ultraviolet-Visible spectroscopy (UV-VIS), dark field Imaging (DFM), and Transmission electron microscopy (TEM). Following characterization, AuNPs were used in protein adsorption study from blood serum concentration and to observe how the differences in their characterization affected their interactions with blood serum proteins. AuNPs are an interest in the bioanalytical sector due to their optical properties, scattering of light, and high surface-to-volume ratio. A common issue plagues the field: the difficulty of inter/intra laboratory reproducibility from one characterization technique. This further affects the understanding of how AuNPs may react for diagnostic and other applications. The importance of a comprehensive characterization protocol for AuNP products and the need for manufacturers to include product specifications is demonstrated in this study.
Show less - Date Issued
- 2019
- Identifier
- CFE0007842, ucf:52814
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007842