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- ItemAccurate Laboratory Wavelengths of the A1Π(υ' = 0-5)-X1Σ+(υ'' = 0) Vibronic Bands of 12C17O and 12C18O(IOP Science, 2006) Du Plessis, Anton; Rohwer, Erich G.; Steenkamp, Christine M.
Show more Twenty nine rovibronic lines of 12C17O for which laboratory wavelengths were previously unavailable were detected in laser-induced fluorescence excitation spectra of the six vibronic bands A1Π(υ' = 0-5)-X1Σ+(υ'' = 0). Rovibronic lines of 12C16O, 13 C16O, 12C17O, and 12C 18O were detected in each band, allowing accurate determination of the unknown wavelengths using neighboring 12C16O and 13C16O lines as reference. The new wavelength data yield consistent heliocentric velocity values when applied to vacuum ultraviolet observations of 12C17O and 12C 18O in the interstellar medium.Show more - ItemAccurate laboratory wavelengths of the e 3 Σ–(ν' = 5) – X 1 Σ+(ν'' = 0) band of 12C16O(IOP Science, 2010) Dickenson, G. D.; Nortje, A. C.; Steenkamp, C. M.; Rohwer, E. G.; Du Plessis, A.
Show more The forbidden singlet-triplet transitions of carbon monoxide (CO) are important in the interpretation of vacuum ultraviolet interstellar absorption spectra and in particular for the measurement of large CO column densities. Twenty rovibronic lines of the e 3Σ–(ν' = 5) – X 1Σ+(ν'' = 0) band of 12 C 16O for which laboratory wavelengths were previously unavailable were identified in laser-induced fluorescence excitation spectra. Wavelengths were assigned to five rovibronic transitions to an average accuracy of 0.0028 Å. A further 15 lines could not be fully resolved and average wavelengths were measured for these groups of closely spaced lines. A wavelength difference of 0.011 ± 0.0028 Å between the measured wavelengths and the calculated wavelengths in the atlas of Eidelsberg & Rostas demonstrates the need for more experimental data on CO.Show more - ItemAccurate laboratory wavelengths of the vacuum ultraviolet A(v'=3)-X(v''=0) band of 12C17O and 12C18O(IOP Science, 2003) Steinmann, Christine M.; Rohwer, Erich G.; Stafast, Herbert
Show more Six individual rotational lines (J'' ≤ 3) of 12C17O, as well as four of 12C18O, were detected in the A 1Π(v' = 3)-X 1Σ+(v'' = 0) vibronic band, and their wavelengths determined using neighboring 12C16O and 13C16O lines as reference. The measurements (fluorescence excitation spectra) were performed in a pulsed supersonic jet (Ar or Ne as carrier gas) employing a tunable pulsed vacuum ultraviolet radiation source with a narrow bandwidth (~5 GHz). The new spectral data on 12C17O and 12C18O are applied to the interpretation of recent vacuum ultraviolet observations of 12C17O and 12C18O in the interstellar medium.Show more - ItemAdvancing X-ray micro computed tomography in Africa : going far, together(Elsevier, 2019) Du Plessis, Anton; Le Roux, Stephan G.; Tshibalanganda, Muofhe
Show more X-ray micro computed tomography (microCT) is a high resolution non-destructive materials imaging technology and is emerging as a powerful tool for industrial and scientific research applications. The aim of this review paper is to present the capabilities and potential of this technique within an African context. This is done using a representative sample: all work done at the Stellenbosch CT facility during 2018 is used as an overview of the type of work done at such a facility in Africa. Besides the plethora of academic research topics, the most important industrial applications are also discussed, which assisted to keep the Stellenbosch CT facility financially operational. This provides a wider understanding of the opportunities and capabilities of this technique and how it can benefit African researchers and local industries. The question “what is it used for?”, and more specifically “what is it used for in Africa?” is therefore answered. The availability of such X-ray tomography facilities helps to fast-track research by providing local expertise and support in Africa for advancing African science. This model is not only applicable to microCT but applies to any collaborative scientific endeavor in Africa, with success rates depending on the efficient sharing of resources, providing expert skills and advancing African science in Africa. There is an African proverb “if you want to go fast – go alone; if you want to go far – go together”. Clearly, African science will go far by working together in such facilities.Show more - ItemAlpha-cluster structure in the ground state of 40Ca displayed in a (p,pa) knockout reaction(IOP Publishing, 2013) Cowley, A. A.
Show more The analyzing power is very sensitive to details of the reaction mechanism of (p, pα) knockout reactions in the incident energy range of approximately 100 MeV and higher. Whereas distorted wave impulse approximation calculations in the past proved to give an excellent reproduction of analyzing power angular distributions for quasifree (p, pα) reactions on light targets such as 6Li, 9Be and 12C, the situation for 40Ca was not as simple. It is now shown that the theory also offers good agreement with the experimental distribution of the heaviest target nucleus if care is taken to use proper distorted waves which treat α−36Ar properly as a system for which α–elastic scattering is anomalous. Thus it is shown that 40Ca reveals its ground state α–cluster structure in an unambiguous way similar to the light target nuclei.Show more - ItemAnalysis and applications of the generalised Dyson mapping(Stellenbosch : Stellenbosch University, 2004-12) Snyman, Izak; Geyer, H. B.; Scholtz, Frederik G.; Stellenbosch University. Faculty of Science. Dept. of Physics.
Show more ENGLISH ABSTRACT: In this thesis, generalized Dyson boson-fermion mappings are considered. These are techniques used in the analysis of the quantum many-body problem, and are instances of so-called boson expansion methods. A generalized Dyson boson-fermion mapping, or a Dyson mapping for short, is a one-to-one linear but non-unitary operator that can be applied to vectors representing the states of a many-fermion system. A vector representing a fermion system maps onto a vector that is most naturally interpreted as representing a state of a many-body system that contains both bosons and fermions. The motivation for doing such a mapping is the hope that the mapping will reveal some property of the system that simplifies its analysis and that was hidden in the original form. The aims of this thesis are 1. to review the theory of generalized Dyson boson-fermion mappings, 2. by considering a tutorial example, to demonstrate that it is feasible to implement the theory and 3. to find a useful application for a generalized Dyson boson-fermion mapping, by considering a non-trivial model, namely the Richardson model for superconductivity. The realization of the first two aims mainly involve the collecting together of ideas that have already appeared in the literature, into one coherent text. Some subtle points that were treated only briefly due to space restrictions in the journal publications where the theory was first expounded, are elaborated on in the present work. On the other hand, the analysis of the Richardson Hamiltonian that uses a Dyson mapping, goes beyond what has already appeared in the literature. It is the first time that a boson expansion technique is implemented for a system where the roles of both collective and non-collective fermion pairs are important. (The Dyson mapping associates bosons with Cooper pairs, while the fermions not bound in Cooper pairs result in fermions being present in the mapped system as well.) What is found is that the Dyson mapping uncovers non-trivial properties of the system. These properties aid the construction of time-independent perturbation expansions for the stationary states of the system, as well as time-dependent expansions for transition amplitudes between states. The time-independent expansions agree with results that other authors obtained through methods other than boson expansions. The time-dependent expansions, that one would be hard-pressed to develop without a Dyson mapping, might in future prove useful in understanding aspects of the dynamics of ultracold fermi gases, when time-dependent magnetic fields are used to vary the atom-atom interaction strenght.Show more - ItemThe analysis of multi-clustering in heavy nuclei(Stellenbosch : Stellenbosch University., 2020-04) Carolus, Timothy Gary; Wyngaardt, Shaun M.; Malaza, Vusi D.; Stellenbosch University. Faculty of Science. Dept. of Physics.
Show more ENGLISH ABSTRACT: The binary cluster model is the simplest mathematical model which is used to describe a system of strongly interacting, and highly correlated nuclear matter. This study will serve as a means to better understand the phenomenon of nuclear clustering beyond a 208P b-alpha cluster core system. Theoretically predicted observables, such as the cluster decay half-life, positive parity cluster states, and the reduced electric dipole transition (B(E2)) are compared to the available experimentally observed quantities. The results show that the tested systems for various cluster-core configurations, of both a fixed parent nuclei and fixed stable core favoured the phenomenological description of their interaction. A numerical optimization procedure is applied to the core- cluster potential of the binary cluster formalism and is then used as an analytical tool in order to predict the possibility of higher modes of cluster decay in 216Rn.Show more - ItemAngular correlation measurement with the iThemba LABS segmented clover detector(Jagellonian University, 2019) Shirinda, O.; Lawriea, E. A.; Buchera, T. D.; Mthembua, S. H.; Dinoko, T. R. S.; Easton, J. L.; Mtshali, W. X.; Noncolela, S. P.; Duprez, D.; Lawrie, J. J.
Show more Measurements of the angular correlation function W(θ) were performed with the iThemba LABS segmented clover detector. A set of measurements with radioactive sources and irradiated targets was carried out to check the performance of the detector. At short detector-to-source distance, the detector covers the whole range of angles needed for precise angular correlation measurements. Preliminary results show that our detector can measure precisely angular correlation functions, including for transitions with large multipole order such as E3, M4, E4, etc., and deliver mixing ratios δ of mixed magnetic and electric nature.Show more - ItemAnomalous scaling of dynamical large deviations(American Physical Society, 2018) Nickelsen, Daniel; Touchette, Hugo
Show more The typical values and fluctuations of time-integrated observables of nonequilibrium processes driven in steady states are known to be characterized by large deviation functions, generalizing the entropy and free energy to nonequilibrium systems. The definition of these functions involves a scaling limit, similar to the thermodynamic limit, in which the integration time τ appears linearly, unless the process considered has long-range correlations, in which case τ is generally replaced by τξ with ξ≠1. Here, we show that such an anomalous power-law scaling in time of large deviations can also arise without long-range correlations in Markovian processes as simple as the Langevin equation. We describe the mechanism underlying this scaling using path integrals and discuss its physical consequences for more general processes.Show more - ItemAspects of femtosecond pulse shape transfer via difference frequency mixing(Stellenbosch : Stellenbosch University, 2015-12) Botha, Gerda Nicolene; Uys, Hermann; Schwoerer, Heinrich; Stellenbosch University. Faculty of Science. Dept. of Physics.
Show more ENGLISH ABSTRACT: We investigate the generation of shaped femtosecond pulses in the infrared spectral regime via a nonlinear process called di erence frequency mixing. First we develop a detailed model of the process, incorporating pulse propagation during di erence frequency mixing, in the slowly varying envelope approximation. Di erence frequency mixing (DFM) is numerically simulated for several wavelengths, nonlinear crystals and Type I and Type II frequency mixing. The di erent factors in uencing the shape transfer e ciency of a shaped pulse to a di erent wavelength regime, as well as the conversion e ciency, is identi ed and investigated thoroughly by doing a parametric study. The numerical modeling demonstrates that the e ciency, with which a shaped pulse in the near-infrared is transferred to another wavelength regime, depends strongly on the refractive index of the nonlinear medium for the interacting pulses and is optimal when the velocity of the generated pulse equals that of the shaped input pulse. We show that it is possible to control the temporal pulse duration of the generated pulse by using speci c input angles and so manipulating the e ective refractive index of the nonlinear material for the input and generated pulses. It was found that it is possible to temporally broaden or narrow the generated pulse relative to the input pulses. We compare the developed numerical model to experimental measurements. A liquid crystal spatial light modulator (SLM), inserted in a 4f setup, is used to generate the shaped pulses. Experimentally we demonstrate high- delity shape transfer by mixing 795 nm and 398 nm femtosecond pulses in a BBO crystal. The temporal broadening and narrowing of the generated pulse is also shown and compared to the numerical simulations showing excellent agreement with measured results.Show more - ItemAspects of quantum field theories(Stellenbosch : Stellenbosch University, 1997) Van Biljon, Andrew; Scholtz, Frederik G.; Stellenbosch University. Faculty of Science. Department of Physics.
Show more ENGLISH ABSTRACT: In this study project we give a general introduction to quantum field theories. In the first chapter we revise the operator formalism of quantum mechanics as well as the second quantization scheme that is used to describe many-particle systems. In the second chapter we develop the idea of path integrals within a quantum mechanics framework. We then apply path integral formalism developed in chapter two to introduce quantum field theories. We describe a field theory for scalar fields in chapter three and then a field theory for fermion fields in chapter four as well as the renormalization techniques in chapter five. In chapter six we show how scattering amplitudes are related to Green's functions which are derived from the path integral formalism. In the last chapter we give a brief introduction to gauge field theories.Show more - ItemAtmospheric heavy metal deposition in North Macedonia from 2002 to 2010 studied by Moss biomonitoring technique(MDPI, 2020-08-30) Barandovski, Lambe; Stafilov, Trajce; Sajn, Robert; Frontasyeva, Marina; Andonovska, Katerina Baceva
Show more Moss biomonitoring technique was used for a heavy-metal pollution study in Macedonia in the framework of the International Cooperative Program on Effects of Air Pollution on Natural Vegetation and Crops (UNECE IPC Vegetation). Moss samples (n = 72) were collected during the summers of 2002, 2005, and 2010. The contents of 41 elements were determined by neutron activation analysis, atomic absorption spectrometry, and inductively coupled plasma atomic emission spectrometry. Using factor and cluster analyses, three geogenic factors were determined (Factor 1, including Al, As, Co, Cs, Fe, Hf, Na, Rb, Sc, Ta, Th, Ti, U, V, Zr, and rare-earth elements–RE; Factor 4 with Ba, K, and Sr; and Factor 5 with Br and I), one anthropogenic factor (Factor 2, including Cd, Pb, Sb, and Zn), and one geogenic-anthropogenic factor (Factor 3, including Cr and Ni). The highest anthropogenic impact of heavy metal to the air pollution in the country was from the ferronickel smelter near Kavadraci (Ni and Cr), the lead and zinc mines in the vicinity of Makedonska Kamenica, Probištip, and Kriva Palanka in the eastern part of the country (Cd, Pb, and Zn), and the former lead and zinc smelter plant in Veles. Beside the anthropogenic influences, the lithology and the composition of the soil also play an important role in the distribution of the elements.Show more - ItemBayesian parameter estimation for discrete data spectra(Stellenbosch : Stellenbosch University, 2017-12) Wang, Li; Eggers, H. C.; Stellenbosch University. Faculty of Science. Dept. of Physics.
Show more ENGLISH ABSTRACT : Discrete spectra are ubiquitous in physics; for example nuclear physics, laser physics and experimental high energy physics measure integer counts in the form of particles in dependence of angle, wavelength, energy etc. Bayesian parameter estimation ( tting a function with free parameters to the data) is a sophisticated framework which can handle cases of sparse data as well as input of pertinent background information into the data analysis in the form of a prior probability. Bayesian comparison of competing models and functions takes into account all possible parameter values rather than just the best t values. We rst review the general statistical basis of data analysis, focusing in particular on the Poisson, Negative Binomial and associated distributions. After introducing the conceptual shift and basic relations of the Bayesian approach, we show how these distributions can be combined with arbitrary model functions and data counts to yield two general discrete likelihoods. While we keep an eye on the asymptotic behaviour as useful analytical checks, we then introduce and review the theoretical basis for Markov Chain Monte Carlo numerical methods and show how these are applied in practice in the Metropolis-Hastings and Nested Sampling algorithms. We proceed to apply these to a number of simple situations based on simulation of a background plus two or three Gaussian peaks with both Poisson and Negative Binomial likelihoods, and discuss how to select models based on numerical outputs.Show more - ItemBiofilament interacting with molecular motors(Stellenbosch : Stellenbosch University, 2015-12) Meylahn, Janusz Martin; Muller-Nedebock, Kristian K.; Touchette, Hugo; Stellenbosch University. Faculty of Science. Dept. of Physics.
Show more ENGLISH ABSTRACT: We study molecular motors moving along a filament or polymer using two different mathematical models in which motors are idealised as springs. In the first model we study the average and the fluctuations of the motor stretch by modelling the motion of the motors along the filament using a simple stochastic differential equation with linear friction. We use the notion of stochastic resetting to explicitly include the attachment and detachment dynamics of the motors to and from the filament and study the fluctuations around the most probable value of the mean stretch using methods from large deviation theory. The second model uses methods from field theory to model a dynamic network consisting of a single polymer and many molecular motors. In this case, we develop techniques to include the bias motion of the molecular motors in a weighting factor for the formation of specific networks rather than in the dynamical constraints of the partition function which allows us to study the steady-state of the network using a self-consistency argument and a saddlepoint approximation.Show more - ItemBound states near the interface of a distorted graphene sheet and a superconductor(Stellenbosch : Stellenbosch University, 2011-12) Van Zyl, Hendrik Jacobus Rust; Snyman, Izak; Scholtz, Frederik G.; Stellenbosch University. Faculty of Science. Dept. of Physics.
Show more ENGLISH ABSTRACT: The goal of this thesis is to investigate the effects of distorting a graphene lattice and connect- ing this distorted graphene sheet to a superconductor. At low energies the possible excitation states in graphene are restricted to two distinct regions in momentum space called valleys. Many electronic applications are possible if one can design a graphene system where excitations can be forced to occupy a single valley in a controllable way. Investigating the spectrum of the distorted graphene sheet reveals that, if the chemical potential is chosen to coincide with a bulk Landau level, the normal-superconductor interface always supports propagating modes in both directions. Excitations from opposite valleys travel in opposite directions along the interface. The spectrum of a distorted graphene sheet terminated by an armchair edge, in contrast, is dis- persionless. We verify this insulating nature of the armchair edge for finite samples by numerical means. Furthermore, we verify previous analytical results pertaining to a graphene sheet with NS interface and an applied perpendicular real magnetic field numerically. In the process, it is shown that considering graphene sheets of perfect width is not necessary, as long as the width a few magnetic lengths away from the interface is well-defined. By then considering a finite graphene sheet, terminated by armchair edges, that is distorted and connected to a superconductor, we find bound states near the NS interface that can be changed by distorting the graphene lattice further.Show more - ItemCalculation of a complete set of spin observables for proton elastic scattering from stable and unstable nuclei(American Physical Society, 2018) Yahya, W. A.; Van Der Ventel, B. I. S.; Kaya, B. C. Kimene; Bark, R. A.
Show more A microscopic study of proton elastic scattering from unstable nuclei at intermediate energies using a relativistic formalism is presented. We have employed both the original relativistic impulse approximation (IA1) and the generalized impulse approximation (IA2) formalisms to calculate the relativistic optical potentials, with target densities derived from relativistic mean field (RMF) theory using the NL3 and FSUGold parameter sets. Comparisons between the optical potentials computed using both IA1 and IA2 formalisms and the different RMF Lagrangians are presented for both stable and unstable targets. The comparisons are required to study the effect of using IA1 versus IA2 optical potentials, with different RMF parameter sets, on elastic scattering observables for unstable targets at intermediate energies. We also study the effect of full-folding form versus the factorized form of the optical potentials on elastic scattering observables. As with the case for stable nuclei, we found that the use of the full-folding optical potential improves the scattering observables (especially spin observables) at low intermediate energy (e.g., 200MeV). No discernible difference is found at a projectile incident energy of 500MeV. To check the validity of using localized optical potential, we calculate the scattering observables using nonlocal potentials by solving the momentum space Dirac equation. The Dirac equation is transformed to two coupled Lippmann-Schwinger equations, which are then numerically solved to obtain elastic scattering observables. The results are discussed and compared to calculations involving local coordinate-space optical potentials.Show more - ItemCave front tracking experiment(Stellenbosch : Stellenbosch University, 2016-12) Green, Mark; Muller-Nedebock, Kristian; Boonzaaier, Leandro; Lynch, Richard; Stellenbosch University. Faculty of Science. Department of Physics
Show more ENGLISH ABSTRACT : Seismic tomography, a procedure to trace seismic wave velocity variation, has been used for more than 100 years to “see through rock”. Initially the recording of seismic waves from natural sources (earthquakes) using seismographs, provided the first evidence of the crust - mantle boundary. Further development of recording techniques and use of explosive seismic sources were employed for the delineation of the geological structures of mineral deposits (primarily oil and gas) as well as detailing the earth - mantle location and geometry. Ultra sonic techniques have been applied in the laboratory experiments to characterise rock sample velocities and its relationship to changes in temperature and stress. Active seismic tomography for hydrocarbon resources determination as well as for the earth structure utilized both reflection and refraction techniques. During the early 60’s seismic techniques were employed in active mines to investigate rock properties for geotechnical purposes. The objective of the Cave Front Tracking Experiment was to investigate whether active seismic tomography could potentially be used to track the cave back progression of a block cave mine. A small scale experiment was conducted to study the variations in seismic travel times associated with ray path refraction caused by stress changes and changes in the rock fabric induced by sub-level mining. A piezoelectric transducer was employed as an active seismic source and a seismic recording system was installed to monitor a volume of rock through which sub-level mining was propergated. Implementation involved the deployment of 11 seismic detectors and the recording of pre-stacked data. The experimental details and hardware characteristics are discussed, which includes technical problems encountered, the process and techniques of significant data stacking in order to recover weak signals generated by a piezoelectric seismic source and travel time variation calculation using signal cross-correlation. Signal travel time variation measurements were made over the course of a year and a half (2013-14), however only five months are investigated in detail and related to mining activities. Finite difference numerical modelling was also employed in order to create a better understanding of the sub-level mining process and its effect on seismic signal delay change. Technical problems associated with the signal processing and signal behavior interacting with an advancing mining front were identified and a number of techniques were employed to overcome problems faced by routine cave front estimation in a working mine environment. The field testing of a prototype impact source that is pneumatically driven and an eccentric rotating mass device is discussed.Show more - ItemCharacterization of the pre-eminent 4-α cluster state candidate in 16O(Stellenbosch : Stellenbosch University, 2015-12) Li, Kevin Ching Wei; Papka, Paul; Neveling, Retief; Adsley, Philip; Stellenbosch University. Faculty of Sciences. Dept. of Physics.
Show more ENGLISH ABSTRACT: Please see full text for abstractShow more - ItemCharacterization of the proposed 4−α cluster state candidate in ¹⁶O(American Physical Society, 2017) Li, K. C. W.; Neveling, R.; Adsley, P.; Papka, P.; Smit, F. D.; Brummer, J. W.; Diget, C. Aa.; Freer, M.; Harakeh, M. N.; Kokalova, Tz.; Nemulodi, F.; Pellegri, L.; Rebeiro, B.; Swartz, J. A.; Triambak, S.; Van Zyl, J. J.; Wheldon, C.
Show more The 0¹⁶O(α,α′) reaction was studied at θlab=0∘ at an incident energy of Elab=200 MeV using the K600 magnetic spectrometer at iThemba LABS. Proton decay and α decay from the natural parity states were observed in a large-acceptance silicon strip detector array at backward angles. The coincident charged-particle measurements were used to characterize the decay channels of the 0⁺₆ state in ¹⁶O located at Ex=15.097(5) MeV. This state is identified by several theoretical cluster calculations to be a good candidate for the 4−α cluster state. The results of this work suggest the presence of a previously unidentified resonance at Ex≈15 MeV that does not exhibit a 0⁺ character. This unresolved resonance may have contaminated previous observations of the 0⁺₆ state.Show more - ItemCharge carrier effects in free standing Si membranes investigated by linear and second harmonic optical techniques(Stellenbosch : Stellenbosch University, 2016-12) Ndebeka, Wilfrid Innocent; Rohwer, Erich G.; Neethling, Pieter N.; Steenkamp, Christine M.; Stafast, Herbert; Stellenbosch University. Faculty of Science. Dept. of Physics
Show more ENGLISH ABSTRACT : Silicon (Si) based materials have been of technological importance throughout the years and today silicon remains a leading material in microelectronics industries. The silicon/silicon dioxide (Si/SiO2) interface has been one of the most studied systems in the realms of material and condensed matter physics. Despite the great outpouring research and huge technological success, there has been little effort to construct a comprehensive, unified microphysical model of the Si/SiO2 interface. The optical properties, both linear and nonlinear, of the interface region are of interest since they vary considerably from those of the adjacent bulk phases. Second harmonic generation is used as a versatile tool to investigate surfaces and buried interfaces of centrosymmetric materials such as Si. Specifically, the electric field induced second harmonic (EFISH) generation process is used as a valuable technique to investigate the mechanisms of charge transfer and trap generation and population, both by electrons and holes being pumped across the interface. In this work, the transmission of the fundamental laser beam (90 fs pulse trains at 80MHz repetition rate, 800 nm) through 10 m to 30 m thick silicon (Si) membranes as well as simultaneous measurements of the electric field induced second harmonic (EFISH) generated in reflection from and transmission through the Si membranes are reported for the first time. The transmission of the laser power through Si membranes, irradiated at an incident angle of 45 , shows an increase with increased power, then reaches a maximum, and finally continues to decrease considerably as the incident power is increased. A similar behavior is observed with the EFISH signals in transmission of the Si membranes. The nonlinear behavior of the fundamental transmitted signal is attributed to free charge carrier absorption (FCA) in Si. The experimental setup and these results are discussed in this thesis.Show more