Bibliographies thématiques / Terahertz, Spectroscopy, Nonlinear Optics

Littérature scientifique sur le sujet « Terahertz, Spectroscopy, Nonlinear Optics »

Auteur : Grafiati

Publié le 10 mars 2023

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Articles de revues sur le sujet "Terahertz, Spectroscopy, Nonlinear Optics"

SHAN, JIE, AJAY NAHATA et TONY F. HEINZ. « TERAHERTZ TIME-DOMAIN SPECTROSCOPY BASED ON NONLINEAR OPTICS ». Journal of Nonlinear Optical Physics & ; Materials 11, n^o 01 (mars 2002) : 31–48. http://dx.doi.org/10.1142/s0218863502000845.

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We present a brief review of the use of nonlinear optics for broadband terahertz (THz) time-domain spectroscopy with femtosecond laser pulses. The generation of THz pulses is accomplished by optical rectification and coherent detection by electro-optic sampling or field-induced second-harmonic generation. The approach permits exceptional time response, as well as the possibility for multichannel detection schemes.

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Rasekh, Payman, Akbar Safari, Murat Yildirim, Ravi Bhardwaj, Jean-Michel Ménard, Ksenia Dolgaleva et Robert W. Boyd. « Terahertz Nonlinear Spectroscopy of Water Vapor ». ACS Photonics 8, n^o 6 (25 mai 2021) : 1683–88. http://dx.doi.org/10.1021/acsphotonics.1c00056.

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Pan, Shubao, Huo Zhang, Zhi Li, Tao Chen et Xianhua Yin. « Quantitative Determination of Sucrose Adulterated in Red Ginseng by Terahertz Time-Domain Spectroscopy (THz-TDS) with Monte Carlo Uninformative Variable Elimination (MCUVE) and Support Vector Regression (SVR) ». Journal of Spectroscopy 2022 (27 février 2022) : 1–10. http://dx.doi.org/10.1155/2022/5847819.

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This paper introduces a method to detect the content of sucrose, an adulterant of red ginseng, based on terahertz spectroscopy. Experiments were carried out on red ginseng with 6 levels of adulterated concentrations using terahertz time-domain spectroscopy (THz-TDS). We separately extracted the information of the terahertz spectral curve by principal component analysis (PCA) and Monte Carlo uninformative variable elimination (MCUVE) and then separately performed quantitative analysis by partial least squares regression (PLSR) and support vector regression (SVR). Because the nonlinear line factor in the terahertz spectral curve of red ginseng samples is considered, the MCUVE-SVR has high correlation coefficient (>0.99) and ratio prediction to deviation (>7.4), low root means square error of deviation (<1.2%), and Bias (<0.05%). The results prove that MCUVE-SVR can be regarded as an ideal quantitative analysis method in the detection of sucrose incorporation in red ginseng by terahertz spectroscopy.

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Partini, Juliasih, Kamsul Abraha, Arief Hermanto, Satoshi Tomita et Matsui Takahiro. « Kajian Gejala Penyearahan Optik pada Metamaterial Chiral ». INDONESIAN JOURNAL OF APPLIED PHYSICS 4, n^o 02 (10 février 2017) : 149. http://dx.doi.org/10.13057/ijap.v4i02.4980.

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<p>Chiral metamaterial is a new breakthrough in the fabrication of a metamaterial because of the capability of providing different refractive index values for each circular polarization angle. This provides opportunities to obtain negative refractive index values, without the necessity to have simultaneously negative values for both permittivity and permeability. This study investigated the optical rectification, which is the phenomenon of second order non-linear optics in the chiral metamaterial. This relates to the testing of the new designs of square structure chiral metamaterial. Optical rectification is often used to 'rectify' femtoseconds laser from the realm of visible light into the terahertz domain. Nonlinear response of metamaterial was observed by terahertz emission spectroscopy. The results showed that the obtained terahertz signal is proportional to the square of the laser power used. This suggests that in the<br />incoherent optical rectification, there is a mixture of optical rectification with the second harmonic wave generation. Development of square-structured chiral metamaterials is expected to be an alternative source of material due to the lack of non-linear material that can be used in the terahertz domain.</p>

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George, Deepu K., Andreas V. Stier, Chase T. Ellis, Bruce D. McCombe, John Černe et Andrea G. Markelz. « Terahertz magneto-optical polarization modulation spectroscopy ». Journal of the Optical Society of America B 29, n^o 6 (25 mai 2012) : 1406. http://dx.doi.org/10.1364/josab.29.001406.

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Vitiello, Miriam S., Luigi Consolino, Massimo Inguscio et Paolo De Natale. « Toward new frontiers for terahertz quantum cascade laser frequency combs ». Nanophotonics 10, n^o 1 (7 octobre 2020) : 187–94. http://dx.doi.org/10.1515/nanoph-2020-0429.

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AbstractBroadband, quantum-engineered, quantum cascade lasers (QCLs) are the most powerful chip-scale sources of optical frequency combs (FCs) across the mid-infrared and the terahertz (THz) frequency range. The inherently short intersubband upper state lifetime spontaneously allows mode proliferation, with large quantum efficiencies, as a result of the intracavity four-wave mixing. QCLs can be easily integrated with external elements or engineered for intracavity embedding of nonlinear optical components and can inherently operate as quantum detectors, providing an intriguing technological platform for on-chip quantum investigations at the nanoscale. The research field of THz FCs is extremely vibrant and promises major impacts in several application domains crossing dual-comb spectroscopy, hyperspectral imaging, time-domain nanoimaging, quantum science and technology, metrology and nonlinear optics in a miniaturized and compact architecture. Here, we discuss the fundamental physical properties and the technological performances of THz QCL FCs, highlighting the future perspectives of this frontier research field.

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Bostak, J. S., D. W. van der Weide, D. M. Bloom, B. A. Auld et E. Özbay. « All-electronic terahertz spectroscopy system with terahertz free-space pulses ». Journal of the Optical Society of America B 11, n^o 12 (1 décembre 1994) : 2561. http://dx.doi.org/10.1364/josab.11.002561.

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Matsunaga, Ryusuke, et Ryo Shimano. « Nonlinear terahertz spectroscopy of Higgs mode in s-wave superconductors ». Physica Scripta 92, n^o 2 (9 janvier 2017) : 024003. http://dx.doi.org/10.1088/1402-4896/aa5327.

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Begušić, Tomislav, Xuecheng Tao, Geoffrey A. Blake et Thomas F. Miller. « Equilibrium–nonequilibrium ring-polymer molecular dynamics for nonlinear spectroscopy ». Journal of Chemical Physics 156, n^o 13 (7 avril 2022) : 131102. http://dx.doi.org/10.1063/5.0087156.

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Two-dimensional Raman and hybrid terahertz-Raman spectroscopic techniques provide invaluable insight into molecular structures and dynamics of condensed-phase systems. However, corroborating experimental results with theory is difficult due to the high computational cost of incorporating quantum-mechanical effects in the simulations. Here, we present the equilibrium–nonequilibrium ring-polymer molecular dynamics (RPMD), a practical computational method that can account for nuclear quantum effects on the two-time response function of nonlinear optical spectroscopy. Unlike a recently developed approach based on the double Kubo transformed (DKT) correlation function, our method is exact in the classical limit, where it reduces to the established equilibrium-nonequilibrium classical molecular dynamics method. Using benchmark model calculations, we demonstrate the advantages of the equilibrium–nonequilibrium RPMD over classical and DKT-based approaches. Importantly, its derivation, which is based on the nonequilibrium RPMD, obviates the need for identifying an appropriate Kubo transformed correlation function and paves the way for applying real-time path-integral techniques to multidimensional spectroscopy.

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Sharma, G., L. Razzari, F. H. Su, F. Blanchard, A. Ayesheshim, T. L. Cocker, L. V. Titova et al. « Time-Resolved Terahertz Spectroscopy of Free Carrier Nonlinear Dynamics in Semiconductors ». IEEE Photonics Journal 2, n^o 4 (août 2010) : 578–92. http://dx.doi.org/10.1109/jphot.2010.2050873.

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Thèses sur le sujet "Terahertz, Spectroscopy, Nonlinear Optics"

Peter, F. « Advanced emitters and detectors for terahertz time-domain spectroscopy ». Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-61479.

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The idea of terahertz-time-domain spectroscopy (THz-TDS) is to exploit a single cycle, spectrally broad THz radiation pulse to gain insight into the response of matter. Photoconductive devices and nonlinear crystals are utilized in both the generation as well as the coherent detection of THz radiation. The relatively high cost and the complexity of commonly used titanium-sapphire lasers hinder a more widespread use of pulsed THz systems for commercial applications. Er-doped femtosecond fiber lasers operating at 1.55 μm could offer a viable alternative. In this thesis nonlinear crystals and photoconductive emitters are discussed for excitation in the near infrared (NIR) window of between 800 nm to 1550 nm. The main focus of this thesis is a detailed study of substrate materials for an interdigitated photoconductive antenna. Photoconductive antennas with microstructured electrodes provide high electric acceleration fields at moderate voltages because of small electrode separations. The scalability of these devices allows for large active areas in the mm^2 range, which are sufficient for excitation at large optical powers. In comparison with conventional emitter structures, these antennas have more favourable characteristics regarding THz power, spectral properties, and ease of handling. Depending on the utilized substrate material, photoconductive antennas can then be operated using different excitation wavelengths. By employing substrates with short carrier trapping times these antennas can be operated as THz-detectors. Moreover the design of electrode structures for generating radially and azimuthally polarized THz waves are presented. A second topic deals with the signal analysis and signal interpretation of THz pulses transmitted through several material systems. These experiments show the potential for tomographic and spectroscopic applications. The third part deals with THz emission by frequency mixing in nonlinear organic and inorganic crystals. Hereby the focus is on polaritonic phase matching in GaAs. Furthermore, indications of THz tunability by the excitation wavelength were found by utilizing waveguide structures. However, the observed tuning range is much lower then theoretically predicted. Specific reasons for this are discussed.

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Rasekh, Payman. « Kerr Effect at the THz Frequencies ». Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41085.

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This doctoral dissertation focuses on the nonlinear optical response of water vapour as well as some solids at terahertz (THz) frequencies. In this study, the propagation of broadband single-cycle THz pulses through a medium with the third-order nonlinear optical response is theoretically investigated. Also, a technique to measure the nonlinear response of transparent materials based on the time-domain THz spectroscopy is developed, which provides frequency dispersion curves of the nonlinear Kerr coefficient (n₂). A numerical model is used to simulate the THz pulse propagation. This model takes into account non-paraxial effects, self-focusing, and diffraction, as well as dispersion, in both the linear and nonlinear optical regimes. The contribution of non-instantaneous Kerr-type nonlinearity to the overall instantaneous and delayed Kerr effect at the THz frequencies is investigated. It is shown how increasing the nonlinear relaxation time and its dispersion modifies the THz pulse after the propagation through a transparent medium. The effect of linear dispersion on self-action during pulse propagation is also discussed. Moreover, the nonlinear spectroscopy of water vapour at THz frequencies is reported. Atmospheric water vapour has a rich spectrum with several strong resonances at frequencies below 3 THz, falling within the range of operation of most existing THz sources. An extremely large nonlinear response to THz radiation is observed at the positions of these resonances. Using the optical Kerr model for the nonlinear response, a minimum nonlinear refractive index of the order of 10² m²/W is estimated. The results provide insight into the energy levels of the water molecule and give a more accurate picture of its response to electromagnetic radiation, paving the way to more accurate THz spectroscopy, imaging, and sensing systems, and thereby facilitating future emerging THz technologies. Finally, the nonlinear response of solids at THz frequencies is studied. It has been shown that a phonon-induced THz Kerr effect can result in a larger nonlinear refractive index than the nonlinear refractive index at the visible or near-infrared range (optical Kerr effect). This pronounced nonlinear optical behavior is verified using a time-domain characterization approach. The results indicate a large delay occurred to the THz fields as they transmit through some of the material samples. In the frequency domain, the induced nonlinear phase shift of the intense THz field is shown to be relatively large of the order of 0.1 rad. From the phase information, the nonlinear phase is extracted by which the dispersion profile of n₂ is obtained.

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Bernerd, Cyril. « Génération d'ondes TeraHertz par Différence de Fréquence ». Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT061/document.

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Le domaine des ondes TeraHertz (THz) s’étend de l’infrarouge lointain (15 μm / 20 THz) aux ondes radios (3000 μm / 0.1 THz). La couverture spectrale des sources actuelles, qu’elles soient thermique (lampes à mercure…), électronique (diode Gunn…) ou optique (laser, antennes…), ne permet pas de répondre à l’ensemble des applications en spectroscopie et en imagerie. Une alternative à ces sources est l’optique non linéaire paramétrique, qui permet de générer des ondes THz à partir du processus de Différence de Fréquences (DFG), et qui consiste à injecter un ou deux lasers dans un cristal non linéaire. Afin de couvrir au mieux le très large domaine THz, il est nécessaire de déterminer un ensemble de cristaux dont les propriétés optiques permettent de générer ces ondes avec de forts rendements de conversion.Le travail présenté dans ce manuscrit de thèse décrit l’étude de ces propriétés pour un ensemble de cristaux non linéaires, ainsi que des résultats expérimentaux de génération THz à partir de la DFG entre deux lasers monochromatiques en régime nanoseconde et picoseconde, ou entre deux composantes de Fourier au sein d’une impulsion laser femtoseconde. Nous avons sélectionné vingt nouveaux cristaux jamais étudiés dans le domaine THz auparavant, ainsi que le nouveau cristal organique de BNA. Nous avons mesuré leurs spectres de transmission du visible au THz, ainsi que les propriétés optiques non linéaires incluant les conditions d’accord de phase et le rendement de conversion
THz-waves extend from the far InfraRed (15 μm – 20 THz) to radio waves (3000 μm – 0.1 THz). Current sources based on thermal (Mercury lamps…), electronics (Gunn diode...) or optics (laser, antennas…) technologies can’t cover this wide spectral range for applications in spectroscopy and imaging. An alternative is provided by parametric nonlinear optics, which leads to the generation of THz waves from Difference Frequency Generation (DFG) by injecting one or two lasers in a nonlinear crystal. To better cover the wide THz domain, it is necessary to determine nonlinear crystals with optical properties leading to the generation of such waves with high conversion efficiencies.This PhD thesis is devoted to the study of these properties for a panel of nonlinear crystals, along with experimental results of THz generation from DFG between two monochromatic lasers in the nanosecond and picosecond regimes, or between two Fourier components within a femtosecond laser. We selected twenty new crystals never studied before in the THz domain, along with the organic crystal of BNA. We measured their transmission spectra from visible to THz, and their nonlinear properties including phase-matching conditions and conversion efficiency

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Nguyen, Alisée. « Contrôle de rayonnements térahertz intenses produits par lasers femtosecondes et applications à la détection de molécules ». Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS020/document.

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Les ondes térahertz (THz), situées entre l'infrarouge et les micro-ondes dans le spectre électromagnétique, correspondent aux fréquences caractéristiques de nombreux mouvements moléculaires et permettent ainsi de caractériser des molécules complexes par spectroscopie dans le domaine temporel. Cette thèse a pour objectif d'étudier les champs THz émis par une source constituée d'une impulsion laser à deux couleurs générant un plasma par ionisation de l'air. En raison de l'asymétrie temporelle du champ laser, un courant électronique présentant une composante basse-fréquence dans la gamme THz est formé dans le plasma par conversion non linéaire et produit un champ secondaire comprenant une composante THz. Les effets non linéaires intervenant dans la génération du rayonnement THz sont l'effet Kerr à basse intensité (< 10¹³ W/cm²) et les photocourants à plus haute intensité (> 10¹³ W/cm²), au-dessus du seuil d'ionisation. Ce dernier mécanisme, qui génère le plus de rayonnement THz, est principalement étudié dans ce manuscrit. Si la puissance crête de l'impulsion laser est suffisamment élevée, des filaments de lumière peuvent être formés par combinaison de l'effet Kerr focalisant et de la formation d'un plasma défocalisant. Le phénomène de filamentation laser permet ainsi de créer des ondes THz à distance. En modulant l'impulsion laser, il est aussi possible de modifier les champs et spectres THz associés. En particulier, nous étudions les effets d'une dérive de fréquence et de la combinaison de multi-impulsions sur l'efficacité de conversion laser-THz. Nous consacrons en outre une large part de nos études à l'influence de l'augmentation de la longueur d'onde laser sur le rendement en énergie de l'émission THz
The terahertz waves (THz), located between the infrared and the microwaves in the electromagnetic spectrum, correspond to the characteristic frequencies of numerous molecular motions and thus make it possible to characterize complex molecules by time-domain spectroscopy. This thesis aims to study the THz fields emitted by a source formed by a two-color laser pulse generating a plasma by air ionization. Due to the time asymmetry of the laser field, an electric current having a low-frequency component in the THz range is formed in the plasma by nonlinear conversion, generating a secondary field including a THz component. The nonlinear effects involved in the generation of THz radiation are the Kerr effect at low intensity (< 10¹³ W/cm²) and the photocurrents at higher intensity (> 10¹³ W/cm²), above the ionization threshold. This latter mechanism, which generates the most THz radiation, is mainly studied in this manuscript. If the peak power of the laser pulse is sufficiently high, light filaments can be created by combining the focusing Kerr effect and the defocusing action of the plasma. So, the filamentation process can produce THz waves remotely. By modulating the laser pulse, it is possible to modify the associated THz fields and spectra. In particular, we study the effects of pulse chirping and multi-pulse combination. We also devote a large part of our studies to the influence of increasing the laser wavelength on the THz energy yield

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Singh, Rohit. « Modulated orientation sensitive terahertz spectroscopy ». Thesis, State University of New York at Buffalo, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3565883.

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The energies of protein correlated motions lie in the far infrared or THz frequency range (λ = 1 cm – 50 mm, f = 0.03 – 6 THz). The existence of correlated motions has been confirmed by neutron and inelastic x-ray scattering measurements. These techniques require large sample volumes and specialized facilities, limiting their application to systematic studies of changes in correlated motions with functional state and allosteric interactions. Standard terahertz time domain spectroscopy measurements have shown sensitivity to protein-ligand binding, oxidation state, conformation, temperature and hydration. However, the response is broad, in part from the large vibrational density of states and in part from the dielectric response contribution from surface water and side-chains.

As an overall strategy to measure the correlated structural motions in protein, we use anisotropic and birefringent behavior of molecular crystals to develop a new technique called MOSTS (Modulated Orientation Sensitive Terahertz Spectroscopy). We achieve high sensitivity and mode separation, by using single molecular crystal such as sucrose and oxalic acid, and rapid modulation of the relative alignment of the terahertz polarization and the crystal axes by rotating the sample. By locking into the signal at the rotation frequency, we determine the polarization sensitive signal and map out the optically active vibrational resonances. To illustrate the technique, we compare our measured spectra with the calculated, and find a close agreement.

We measure dielectric properties of oxalic acid, sucrose and protein crystals and polycarbonate sheet using standard terahertz time domain spectroscopy. We determine the absorbances in oxalic acid and sucrose crystals, using MOSTS technique. We compare the resonances in these two distinct methods. Then, we develop a protein model sample by sticking together two thin plates of sucrose and polycarbonate. We carry out standard THz-TDS and MOSTS measurements on the protein model sample. We show that we are able to isolate the vibrational modes from glassy background in protein model sample by using MOSTS.

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Brandt, Nathaniel Curran. « Developments and advances in nonlinear terahertz spectroscopy ». Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91110.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references.
Nonlinear terahertz (THz) spectroscopy is a rapidly developing field, which is concerned with driving and observing nonlinear material responses in the THz range of the electromagnetic spectrum. In this thesis, I present several advances in nonlinear THz spectroscopy that expand the range of systems in which responses may be driven, the types of responses that may be initiated, and the way in which these responses may be observed. Sufficiently strong THz pulses are generated using the tilted-pulse-front technique, and are collected, focused, and detected using a THz spectrometer specifically designed for maximum peak THz electric field strength and maximum flexibility, allowing for a wide range of experimental geometries to be implemented. Further enhancement in the peak THz electric field strength is obtained through the use of metamaterial structures, which concentrate free-space THz fields in their antenna gaps. Impact ionization was observed in high-resistivity silicon, a material in which no nonlinear THz response had been previously seen, using metamaterial structures to enhance free space THz electric fields. Using three-dimensional metamaterial structures, the THz magnetic field is shown to also be capable of driving ionization processes both in high-resistivity silicon as well as air. Using metamaterial structures with open gaps, the THz electric field is shown to induce breakdown in air at both high and low pressures due to field ionization processes involving the gold metamaterial antennas. Furthermore, THz-driven electromigration of the gold metamaterial antennas is observed. Probing of THz-driven structural changes in both vanadium dioxide and perovskite ferroelectrics is demonstrated using femtosecond Xray pulses from the LCLS facility at the SLAC National Accelerator Laboratory. Finally, ongoing results involving energetic materials, stimulated Raman measurements, and Stark effect measurements are discussed. This work, coupled with the ongoing expansion of nonlinear THz techniques and potential applications demonstrates the continued development of nonlinear THz spectroscopy into a robust and valuable method for investigating fundamental processes in a multitude of systems.
by Nathaniel Curran Brandt.
Ph. D.

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Kühn, Wilhelm. « Nonlinear terahertz spectroscopy in one and two dimensions ». Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2011. http://dx.doi.org/10.18452/16286.

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Die vorliegende Dissertation behandelt Grundlagen und Anwendungen der nichtlinearen Terahertzspektrospie (THz). Diese Arbeit zeigt erstmalig, dass sich die Inversion des Quantenkaskadenlasers nach einer Störung schon innerhalb von hundert Femtosekunden wieder erholt. Außerdem wurde der exakte Generationsprozess von THz Impulsen in einem Laser-induzierten zwei-Farben Plasma untersucht. Durch Vergleich mit Simulationen wird eindeutig der Ionisationsstrom im Plasma als Quelle der THz Strahlung identifiziert. Neue Spektroskopiemethoden in ein und zwei Zeitdimensionen werden entwickelt und auf verschiedene Halbleiterstrukturen angewendet. So wird das elektrische Feld des THz-Impulses für Hochfeld-Transportexperimente genutzt. Im quanten-kinetischen Regime entkoppelt die Elektronbewegung von den Phononmoden des Kristalls, und quasi-ballistischer Transport wird möglich. Wir entwickeln ein dynamisches Polaronmodell, welches sowohl die experimentellen Ergebnisse auf kurzen Zeitskalen als auch Literaturwerte auf langen Zeitskalen zuverlässig reproduziert. Bei niedrigen Temperaturen von 80 K tritt zusätzlich THz-induziertes Interbandtunneln in GaAs auf. Die temperaturabhängige Tunnelrate hängt dabei wesentlich von der Dekohärenzrate des induzierten Prozesses ab. Desweiteren wird eine kollineare 2D THz Spektroskopiemethode entwickelt und erstmals an Quantentrogstrukturen angewendet. Eine komplizierte, nichtkollineare Strahlgeometrie ist prinzipiell nicht notwendig. Die eingeführten Frequenzvektoren erklären das zugrundeliegende N-Wellen Mischen analog zum Raum auch in der Zeit. So werden mit einer kollinearen Strahlgeometrie alle nichtlinearen Signale simultan gemessen werden. Mit diesem Konzept wurden Rabi-Oszillationen an Intersubbandübergängen in Signale verschiedener nichtlinearer Ordnung zerlegt. Die ersten 2D Korrelationsspektren im THz-Bereich demonstrieren die energetischen Kopplungen zwischen verschiedenen polaronischen Zuständen in einer Doppel-Quantentrogstruktur.
The presented thesis concerns fundamentals and applications of nonlinear terahertz (THz) spectroscopy. It is demonstrates that the a gain recovery time of a quantum cascade laser (QCL) amounts only to several hundred femtoseconds. We explored the generation process of THz pulses within a laser-induced two-color plasma and identified the ionisation current as the origin of the THz radiation. Novel methods of THz spectroscopy in one and in two dimensions are developed and applied to different semiconductor heterostructures. We use the electric field of THz pulses for high-field transport experiments. Within this quantum-kinetic regime, the electron velocity decouples from phonon modes of the crystal lattice and quasi-ballistic transport becomes feasible during the first hundreds of femtoseconds. We develop a dynamic polaron model, which reproduces the experimental results on short time scales as well as the published values on long time scales. At low temperatures of 80 K, we find additional THz-induced interband tunneling in GaAs. The temperature dependent tunneling rate depends essentially on the decoherence time of the induced process. Furthermore, a novel method of collinear 2D THz spectroscopy is developed and applied to quantum well structures. Frequency vectors are introduced to explain the underlying process of N-wave mixing not in space, but in time. This allows for a collinear beam geometry to measure all nonlinear signals simultaneously. We used this new method to decompose Rabi oscillations on intersubband transitions into nonlinear signals of different order. The first 2D correlation spectra in the THz frequency range demonstrate energetic couplings between polaronic states within an asymmetric double quantum well structure. Another experiment displays for the first time the 2D correlation spectrum of a 2pi Rabi flop on the intersubband transition of a multiple quantum well structure.

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Ould-Hamouda, Amine. « Étude des transitions de phase photo-induites dans des matériaux métalliques et organométalliques ». Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0112/document.

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Ces travaux de thèse portent sur l'étude des transitions de phases photo-induites dans différents matériaux métalliques et organométalliques. Les études présentées ont été guidées par la problématique liée à l'enregistrement et au stockage d'informations numériques. Tout d’abord, nous nous sommes intéressés à la spectroscopie THz et Raman de composés à transitions d'état de spin à base de Fe (II). Les spectres obtenus à l’aide de ces deux techniques sont confrontés aux résultats issus de simulations numériques (DFT). Nous avons également étudié la transition d’état de spin induite par des lasers CO2 dans des composés à transition de spin polymériques. Un dispositif expérimental simple permettant l'enregistrement d'information dans ce type de matériaux est proposé. Par la suite, nous avons étudié la transition réversible de la phase métallique (λ métastable à semiconductricer (β stable) dans des nanoparticules d'un oxyde de Titane (Ti3O5), soumis à des impulsions laser nanosecondes. Nous avons étudié plus particulièrement les aspects cinétiques de cette transition. Il apparaît alors que la transition λ→β se produit sur une échelle de plusieurs centaines de nanosecondes, tandis que la transition β→λ se fait en quelques dizaines de nanosecondes. Les mécanismes photoythermiques à l’origine de cette transition permettent de rendre compte de ces observations expérimentales. Enfin, nous avons étudié un complexe bimétallique analogue du bleu de Prusse Rb0.94Mn[Fe (CN)6]0.98.0.3H2O, bistable à température ambiante. Par génération de second et de troisième harmonique, nous avons mesuré les non-linéarités effectives d’ordre deux et trois de ce composé dans les phases basse et haute température. Nous montrons que l’on peut faire photo-commuter les propriétés optiques linéaires et non linéaires de ce composé. La spectroscopie et la génération d’onde THz dans ce matériau sont également présentées et discutées
This thesis is dedicated to the study of laser-induced phase transitions in metallic and metaly organic materials. The studies presented here are guided by the recording and storage of digital information. Firstly, we focused on THz and Raman spectroscopy of two different iron Fe (II) spin crossover complexes. The spectra we recorded using these two methods are compared to numerical simulations obtained with the DFT. We have also studied the spin state transition induced byCO2 lasers in polymeric spin crossover materials. A simple experimental setup allowing data recording in this type of materials is presented. Secondly, we studied the reversible metal (λ metastable to semiconductor (β stable) phasetransition in nanoparticles of a Titanium oxide (Ti3O5), excited with nanosecond laser pulses.More specifically, we studied the kinetic aspects of this transition. It appears that the λ→β transition occurs in hundreds of nanoseconds while the β→λ transition is achieved in a few tens of nanoseconds. The photothermal mechanisms leading to this transition accounts very well to these experimental observations. Finally, we present the study of Rb0.94Mn[Fe (CN)6]0.98.0.3H2O, a Prussian blue analogue which is bistable at room temperature. Using secondy and thirdyharmonic generation, we measured the effective secondy and thirdyorder nonlinearities of this compound in low and high temperature phases. We show that we can photo-switch the linear and nonlinear optical properties of this material. THz spectroscopy and generation in this material are also presented

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Graber, Benjamin. « HIGH POWER TIME DOMAIN TERAHERTZ SPECTROSCOPY ». Diss., Temple University Libraries, 2014. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/301211.

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Physics
Ph.D.
Terahertz (THz) has become a strong area for scientific research and commercial application in recent years. This research group has redesigned and optimized a THz photoconductive antenna, which currently operates with approximately 10x the power of a commercial antenna. It has been determined by this research that the THz signal emitted from a photoconductive antenna consists of coherent and incoherent signals. In addition to the improvement of the THz photoconductive antenna, I have optimized an electro optic THz detection system by characterizing the field dependency of an electro optic crystal, which enabled me to estimate the THz electric field strength. The high power THz source and optimized detection system were combined into a high power, high resolution time domain THz spectrometer. This spectrometer was used to conduct original measurements of the THz spectrum of water vapor, ionized air, and various chemical vapor including explosives. Most of these measurements were only possible with our improved THz spectrometer. In order to understand ionized air, an additional study was carried out to explore the ionization of several gases (e.g. N2, O2, Ar, CO2, and water vapor) which were ionized by radioactive isotopes. This unique study found that in addition to dose rate, the gamma energy of the radioactive isotopes and the sequential ionization levels of gases affect the equilibrium ion densities of these gases. This effect was especially pronounced for argon gas. The study of ion dynamics in gases has lead to the development of a prototype for stand-off detection and identification of radioactive isotopes. This prototype, despite being simple in design, can detect isotopes faster and more cheaply than a conventional gamma ray spectrometer. Throughout this thesis research I have successfully developed a high power, high resolution terahertz spectrometer and demonstrated that with the spectrometer I could identify characteristic resonances of water vapor, some chemicals including explosives, and even ionized air produced by nuclear isotopes. From the characteristic resonance frequencies one can understand the underlying physics or chemistry of molecules or atoms.
Temple University--Theses

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Yeh, Ka-Lo. « The generation of high field terahertz radiation and its application in terahertz nonlinear spectroscopy ». Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/49748.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2009.
Includes bibliographical references (p. 147-155).
In this thesis research, I implemented a terahertz generation scheme that enables high-field near-single-cycle terahertz (THz) pulse generation via optical rectification in a LiNbO3 (LN) crystal. I also developed a method for the non reconfigurable generation of high-intensity multiple-cycle THz fields aimed to more efficiently deliver THz energy to resonant samples. A novel free-space THz-pump/THz-probe setup enabled time-resolved measurement of ultrafast nonlinear electronic responses in doped bulk semiconductor samples. The ability to spectrally and temporally resolve the response of the semiconductor sample using a THz probe allowed us to uncover both the dynamics of impact ionization and interesting phonon-plasma interactions in indium antimonide (InSb) for the first time. Nonlinear vibrational responses in LN were ob-served first in a dual THz beam setup on an integrated LN waveguide platform with optical probing to reveal the generation of terahertz second harmonic signals and also in THz transmission measurements in cooled LN where THz intensity-dependent self-phase modulation and harmonic generation were observed. An outlook and preliminary results toward implementation and observation of high-field THz-driven responses in ferroelectric materials are given in the final chapter of this thesis.
by Ka-Lo Yeh.
Ph.D.

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Livres sur le sujet "Terahertz, Spectroscopy, Nonlinear Optics"

Peiponen, Kai-Erik. Terahertz Spectroscopy and Imaging. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013.

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Satoru, Kano, dir. Introduction to nonlinear laser spectroscopy. Boston : Academic Press, 1988.

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S, Radhakrishna, Tan B. C, University of Malaya. Institute of Advanced Studies. et Malaysian Institute of Physics, dir. Laser spectroscopy and nonlinear optics of solids. New Delhi : Springer-Verlag, 1991.

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Yehiam, Prior, Ben-Reuven Abraham et Rosenbluh Michael, dir. Methods of laser spectroscopy. New York : Plenum Press, 1986.

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1957-, Hunt Jeffrey H., dir. Selected papers on nonlinear optical spectroscopy. Bellingham, Wash : SPIE Optical Engineering Press, 2000.

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Principles of nonlinear optical spectroscopy. New York : Oxford University Press, 1995.

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Rautian, Sergeĭ Glebovich. Kinetic problems of non-linear spectroscopy. Amsterdam, Netherlands : North-Holland, 1991.

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1938-, Chebotaev V. P., dir. Nelineĭnai͡a︡ lazernai͡a︡ spektroskopii͡a︡ sverkhvysokogo razreshenii͡a︡. Moskva : "Nauka," Glav. red. fiziko-matematicheskoĭ lit-ry, 1990.

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1961-, Vartiainen E. M., et Asakura Toshimitsu 1934-, dir. Dispersion, complex analysis and optical spectroscopy : Classical theory. Berlin : Springer, 1999.

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Ultrafast optics. Hoboken, N.J : Wiley, 2009.

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Chapitres de livres sur le sujet "Terahertz, Spectroscopy, Nonlinear Optics"

Murphy, J. Anthony, et Créidhe O’Sullivan. « Terahertz Optics ». Dans Terahertz Spectroscopy and Imaging, 29–56. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-29564-5_2.

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Hoffmann, Matthias C. « Nonlinear Terahertz Spectroscopy ». Dans Terahertz Spectroscopy and Imaging, 355–88. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-29564-5_14.

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Demtröder, Wolfgang. « Nonlinear Optics ». Dans Laser Spectroscopy 1, 385–420. Berlin, Heidelberg : Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-53859-9_6.

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Singhal, Ravi. « Nonlinear Optics ». Dans An Introduction to Laser Spectroscopy, 149–69. Boston, MA : Springer US, 1995. http://dx.doi.org/10.1007/978-1-4613-0337-4_9.

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Wegener, Martin. « Carrier-Wave Nonlinear Optics ». Dans Frontiers of Optical Spectroscopy, 93–186. Dordrecht : Springer Netherlands, 2005. http://dx.doi.org/10.1007/1-4020-2751-6_4.

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Andrews, David L., et Stephen R. Meech. « Nonlinear Optics and Surface Applications ». Dans An Introduction to Laser Spectroscopy, 233–56. Boston, MA : Springer US, 2002. http://dx.doi.org/10.1007/978-1-4615-0727-7_8.

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Bloembergen, N. « Nonlinear Optics and Collective Excitations ». Dans Spectroscopy and Dynamics of Collective Excitations in Solids, 1–15. Boston, MA : Springer US, 1997. http://dx.doi.org/10.1007/978-1-4615-5835-4_1.

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Flytzanis, Ch, G. M. Gale et F. Vallée. « Non-local time-resolved spectroscopy tracking of polariton pulses in crystals ». Dans Frontiers in Nonlinear Optics, 107–35. Boca Raton : CRC Press, 2021. http://dx.doi.org/10.1201/9781003209638-7.

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Grischkowsky, D. « Nonlinear generation of sub-psec pulses of THz electromagnetic radiation by optoelectronics—applications to time-domain spectroscopy ». Dans Frontiers in Nonlinear Optics, 196–227. Boca Raton : CRC Press, 2021. http://dx.doi.org/10.1201/9781003209638-11.

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Blanchard, F., L. Razzari, F. H. Su, G. Sharma, Roberto Morandotti, T. Ozaki, M. Reid et F. A. Hegmann. « The Dawn of Ultrafast Nonlinear Optics in the Terahertz Regime ». Dans Springer Series in Optical Sciences, 297–323. New York, NY : Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-3538-9_11.

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Actes de conférences sur le sujet "Terahertz, Spectroscopy, Nonlinear Optics"

Shimano, Ryo. « Nonlinear terahertz spectroscopy of Higgs mode in superconductors ». Dans Nonlinear Optics. Washington, D.C. : OSA, 2015. http://dx.doi.org/10.1364/nlo.2015.nw3a.4.

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Koch, S. W., M. Kira, J. T. Steiner et D. Golde. « Nonlinear Terahertz Spectroscopy of Semiconductors ». Dans Conference on Lasers and Electro-Optics. Washington, D.C. : OSA, 2009. http://dx.doi.org/10.1364/cleo.2009.jtuc2.

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Hirori, Hideki. « Ultra-intense Terahertz Pulse Generation and Application to Nonlinear THz Spectroscopy ». Dans Nonlinear Optics. Washington, D.C. : OSA, 2013. http://dx.doi.org/10.1364/nlo.2013.nm3b.1.

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Razzari, L., F. Blanchard, F. H. Su, G. Sharma, A. Ayesheshim, T. L. Cocker, L. V. Titova et al. « Terahertz nonlinear spectroscopy of free-carriers in semiconductors ». Dans LEOS 2009 -22nd Annuall Meeting of the IEEE Lasers and Electro-Optics Society (LEO). IEEE, 2009. http://dx.doi.org/10.1109/leos.2009.5343386.

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Hayashi, M., et Y. Fujimura. « Origin of ultrafast dynamics in time-resolved impulsive stimulated Raman scattering (ISRS) from molecules in liquids. » Dans Nonlinear Optics. Washington, D.C. : Optica Publishing Group, 1992. http://dx.doi.org/10.1364/nlo.1992.tud3.

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1. One of the features in ultrashort time-resolved nonlinear coherent scattering spectroscopy is creation of a transient intermolecular coherence in molecular liquids. 1,2 For example, teraheltz quantum beats appear in time-resolved coherent anti-Stokes Raman scattering (CARS) and time-resolved impulsive stimulated Raman scattering (ISRS) profiles as a result of the creation of the intermolecular vibrational coherence. Such time-resolved profiles provide us information on the mechanism of the intermolecular dynamics. Recently, Nelson group has reported the time-resolved ISRS profile of dibromomethane liquid.2 The most distinctive feature is the appearance of 5.2 teraheltz quantum beat with two apparent decay components. The quantum beat is associated with the creation of intermolecular, vibrational coherence between Raman transitions of 173 cm-1 bending mode of dibromomethane molecules at different sites. The time-development behavior was not clarified from the microscopic point of view.

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Woerner, M., P. Gaal, W. Kuehn, K. Reimann, T. Elsaesser et R. Hey. « Nonlinear THz optics—ultrafast spectroscopy ». Dans 2007 Joint 32nd International Conference on Infrared and Millimeter Waves and the 15th International Conference on Terahertz Electronics (IRMMW-THz). IEEE, 2007. http://dx.doi.org/10.1109/icimw.2007.4516676.

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Unikandanunni, Vivek, et Stefano Bonetti. « Terahertz and optical ultrafast electron dynamics in platinum and gold ». Dans Ultrafast Nonlinear Imaging and Spectroscopy IX, sous la direction de Zhiwen Liu, Demetri Psaltis et Kebin Shi. SPIE, 2021. http://dx.doi.org/10.1117/12.2594551.

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De Regis, Michele, Luigi Consolino, Saverio Bartalini, Marco Ravaro et Paolo De Natale. « Broadband CW nonlinear generation for metrological grade terahertz spectroscopy ». Dans 2017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC). IEEE, 2017. http://dx.doi.org/10.1109/cleoe-eqec.2017.8086437.

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Tanaka, Koichiro. « High-power terahertz pulse generation and application to nonlinear spectroscopy ». Dans 2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR). IEEE, 2013. http://dx.doi.org/10.1109/cleopr.2013.6600248.

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Gaal, P., K. Reimann, M. Woerner, T. Elsaesser, R. Hey et K. H. Ploog. « Ultrafast Nonlinear Terahertz Spectroscopy of n-Type GaAs ». Dans Optical Terahertz Science and Technology. Washington, D.C. : OSA, 2007. http://dx.doi.org/10.1364/otst.2007.ma5.

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Rapports d'organisations sur le sujet "Terahertz, Spectroscopy, Nonlinear Optics"

Furtak, T. E. Vibrational spectroscopy of buried interfaces using nonlinear optics. Final technical report, July 7, 1986--February 29, 1996. Office of Scientific and Technical Information (OSTI), mai 1996. http://dx.doi.org/10.2172/286295.

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