Ultra Broadband THz Time-domain Spectroscopy Using Air Photonics PDF Download

Author: Xiaoyu Guo
Publisher:
ISBN:
Category :
Languages : en
Pages : 88

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Author: Francesco D'Angelo
Publisher:
ISBN: 9789463280402
Category :
Languages : en
Pages : 101

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Book Description
"Terahertz (THz) spectroscopy is a well-established technique which allows for measuring the complex-valued dielectric properties of materials, specifically semiconductors, in the THz range. As THz photons have a low energy, typically comparable to intraband transitions, they are ideal probes of important phenomena such as the momentum relaxation of charge carriers and optical phonons. Because of the intrinsic phase-matching limitations imposed by the materials employed in conventional THz emitters and detectors, most femtosecond-laser based THz spectrometers can only cover a narrow spectral range, typically 0.1-3 THz. However, by employing the same laser source as conventional THz spectrometers, an air-photonics based THz spectrometer can access a much broader spectral range, extending beyond 30 THz. As air is virtually non-dispersive, the optical-THz phase-matching condition is automatically met. As a result, intense, sub-50-fs electromagnetic transients can be achieved with THz air photonics. The enhanced characteristics in terms of time-resolution, bandwidth, and field strength offer unique opportunities for THz spectroscopy, such as monitoring the dynamics of the charge carriers on the timescale of the carrier-lattice interaction. In this thesis, we explore the capabilities of THz air photonics by performing steady-state ultra-broadband THz spectroscopy of some common polymers, and transient ultra-broadband THz spectroscopy of, respectively, solution processed methylammonium lead iodide perovskite films and undoped gallium arsenide. In addition, we present explicit guidelines for ultra-broadband transient THz spectroscopy, including a novel method for self-referenced signal acquisition minimizing the phase error, and a numerically-accurate approach to the transient reflectance data analysis."--Samenvatting auteur.

Author: Mira Naftaly
Publisher: Artech House
ISBN: 1608077772
Category : Technology & Engineering
Languages : en
Pages : 386

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Book Description
This new book describes modern terahertz (THz) systems and devices and presents practical techniques for accurate measurement with an emphasis on evaluating uncertainties and identifying sources of error. This is the first THz book on the market to address measurement methodologies and issues -- perfect for practitioners and aspiring practitioners wishing to learn good measurement practice and avoid pitfalls. This book provides a brief review of different THz systems and devices, followed by chapters detailing the measurement issues encountered in using each of the main types of THz systems, and a guide to performing measurements rigorously. Particular attention is given to evaluating uncertainties, and recognizing potential sources of errors. The main focus is on time-domain spectroscopy, by far the most widely used technique. Readers are also presented with examples of applications with the emphasis on utility, both in research and in industry.

Author: V.P. Gupta
Publisher: Elsevier
ISBN: 0128188715
Category : Science
Languages : en
Pages : 706

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Book Description
Molecular and Laser Spectroscopy, Advances and Applications: Volume 2 gives students and researchers an up-to-date understanding of the fast-developing area of molecular and laser spectroscopy. This book covers basic principles and advances in several conventional as well as new and upcoming areas of molecular and laser spectroscopy, such as a wide range of applications in medical science, material science, standoff detection, defence and security, chemicals and pharmaceuticals, and environmental science. It covers the latest advancements, both in terms of techniques and applications, and highlights future projections. Editors V.P. Gupta and Yukihiro Ozaki have brought together eminent scientists in different areas of spectroscopy to develop specialized topics in conventional molecular spectroscopy (Cavity ringdown, Matrix Isolation, Intense THz, Far- and Deep- UV, Optogalvanic ), linear and nonlinear laser spectroscopy (Rayleigh & Raman Scattering), Ultrafast Time-resolved spectroscopy, and medical applications of molecular spectroscopy. and advanced material found in research articles. This new volume expands upon the topics covered in the first volume for scientists to learn the latest techniques and put them to practical use in their work. Covers several areas of spectroscopy research and expands upon topics covered in the first volume Includes exhaustive lists of research articles, reviews, and books at the end of each chapter to further learning objectives Uses illustrative examples of the varied applications to provide a practical guide to those interested in using molecular and laser spectroscopy tools in their research

Author: A. K. Haghi
Publisher: CRC Press
ISBN: 1351659847
Category : Science
Languages : en
Pages : 376

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Book Description
This volume presents an up-to-date review of modern materials and concepts, issues, and recent advances in analytical and physical chemistry. Distinguished scientists and engineers from key institutions worldwide have contributed chapters that provide a deep analysis of their particular subjects. The chapters discuss the composition and properties of complex materials as well as mixtures, processes, and the need for new and improved analytical technology.

Author: Mauro F. Pereira
Publisher: Springer
ISBN: 9402410937
Category : Science
Languages : en
Pages : 196

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Book Description
This work is intended to jointly address the development, realization and applications of emitters and detectors of terahertz (THz-0.3 THz up to 10 THz) and their application to diagnostics of CBRN effects and detection of explosives and CBRN. Hazardous substances typically exhibit rotational and vibrational transitions in this region, hence giving access to spectroscopic analysis of a large variety of molecules which play a key role in security as well as various other areas, e.g. air pollution, climate research, industrial process control, agriculture, food industry, workplace safety and medical diagnostics can be monitored by sensing and identifying them via THz (0.3 to 10 THz) and mid infrared (MIR-10 THz to 100 THz) absorption “finger prints”. Most plastics, textiles and paper are nearly transparent for THz radiation.

Author: Xi-cheng Zhang
Publisher: World Scientific
ISBN: 9811265658
Category : Science
Languages : en
Pages : 297

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Book Description
As a bridge between electronics and photonics, terahertz science and technology has made tremendous progress in the past decades. While terahertz wave generation from gas, solid and plasma with femtosecond laser excitation has been widely used, terahertz liquid photonics is a newly emerging topic in recent years. This book includes the most recent experimental results, theoretical analysis, and simulated calculations on terahertz emission and detection from liquid materials under ultrashort-pulse laser excitation, providing readers a comprehensive understanding of current developments in terahertz liquid photonics. By comparing with traditional sources, distinctive properties of terahertz wave generation from liquids are discussed in detail, which provides a new perspective in exploring laser-matter interactions.

Author: Dheeraj Kumar Singh
Publisher: Springer Nature
ISBN: 9813360844
Category : Technology & Engineering
Languages : en
Pages : 663

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Book Description
The book highlights recent developments in the field of spectroscopy by providing the readers with an updated and high-level of overview. The focus of this book is on the introduction to concepts of modern spectroscopic techniques, recent technological innovations in this field, and current examples of applications to molecules and materials relevant for academia and industry. The book will be beneficial to researchers from various branches of science and technology, and is intended to point them to modern techniques, which might be useful for their specific problems. Spectroscopic techniques, that are discussed include, UV-Visible absorption spectroscopy, XPS, Raman spectroscopy, SERS, TERS, CARS, IR absorption spectroscopy, SFG, LIBS, Quantum cascade laser (QCL) spectroscopy, fluorescence spectroscopy, ellipsometry, cavity-enhanced absorption spectroscopy, such as cavity ring-down spectroscopy (CRDS) and evanescent wave-CRDS both in gas and condensed phases, time-resolved spectroscopy etc. Applications introduced in the different chapters demonstrates the usefulness of the spectroscopic techniques for the characterization of fundamental properties of molecules, e.g. in connection with environmental impact, bio-activity, or usefulness for pharmaceutical drugs, and materials important e.g. for nano-science, nuclear chemistry, or bio-applications. The book presents how spectroscopic techniques can help to better understand substances, which have also great impact on questions of social and economic relevance (environment, alternative energy, etc.).

Author: Xi-Cheng Zhang
Publisher: Springer Science & Business Media
ISBN: 1441909788
Category : Technology & Engineering
Languages : en
Pages : 250

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Book Description
Terahertz (THz) radiation, which is electromagnetic radiation in a frequency int- val from 0.3 to 10 THz (1 mm–30 ?m wavelength), is the next frontier in science and technology. This band occupies a large portion of the electromagnetic sp- trum between the infrared and microwave bands. Basic research, new initiatives, and developments in advanced sensing and imaging technology with regard to the THz band remain unexplored compared to the relatively well-developed science and technology in the microwave and optical frequencies. Historically, THz technologies were used mainly within the astronomy c- munity for studying the background of cosmic far-infrared radiation, and by the laser-fusion community for the diagnostics of plasmas. Since the ?rst demonstration of THz wave time-domain spectroscopy in the late 1980s, there has been a series of signi?cant advances (particularly in recent years) as more intense THz sources and higher sensitivity detectors provide new opportunities for understanding the basic science in the THz frequency range.

Author: Michael Theuer
Publisher: Cuvillier Verlag
ISBN: 3736930593
Category : Science
Languages : en
Pages : 174

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Book Description
The terahertz (THz) band between 100 GHz and 10 THz is particularly interesting for a wide range of applications since it unifies the properties and advantages of the adjoining spectral ranges, the infrared and the millimeter waves. But unfortunately in this spectral range the optical as well as electronic systems can not offer a sufficient performance in terms of power and sensitivity. So in both approaches, new sources and detectors are developed to expand the accessible electromagnetic spectrum into the THz range. In this thesis new developments in the field of optical THz systems for THz time-domain spectroscopy (TDS) are investigated using femtosecond pulses for the coherent generation and detection. New schemes for THz emitters are elaborated. The main aim is to obtain a THz source with high output power in the frequency range between 100 GHz and 4 THz for femtosecond pumped systems. In a cooperation with the RIKEN Institute in Japan an enhancement cavity for the pump radiation is developed. This is an actively stabilized synchronously pumped ring resonator which recycles the unused pump radiation. As THz emitter a lithium niobate crystal in Cherenkov-type geometry is applied. Lithium niobate is particularly well suited as a THz emitter because of its high nonlinearity, high transparency in the near infrared and the well developed poling technique. To guarantee an efficient broadband surface emitting scheme also for long crystals an attached silicon prism is used as THz output coupler. The enhancement cavity is characterized in terms of properties for the near infrared pump pulses as well as for the emitted THz radiation. So far most of all THz-TDS systems are based on pulsed lasers with wavelengths around 800 nm. In order to apply readily available femtosecond fiber lasers at 1.5 μm wavelength, used e. g. in the telecommunication field, new materials for THz emitters have to be investigated. Here results of various emitters based on different semiconductors with pump wavelengths up to 2 μm are presented. For the application of THz radiation different TDS systems are realized. Limiting factors like laser power, pump wavelength, flexibility, space consumption and imaging optics are addressed. Portable systems and fiber based systems are constructed. A special emphasis is placed on a THz imaging system, which is used in feasibility studies for industrial customers. Results of industrial relevant measurements are presented. The recorded THz electric field is typically evaluated in terms of amplitude and phase. This shows a THz image underlining different properties of the device under test. Potential applications are in the field of non-destructive testing and final inspection (geometry, thickness, coatings, interfaces). The detection limit in the time domain is demonstrated for thin layers and calibrated samples. THz spectroscopy also can give the “spectral fingerprint”, an important decision criterion for the sample to be identified (content, substance distribution). Simulants as well as real world explosives and poisons are measured. The advantages of THz time-domain spectroscopy compared to cw or passive THz systems are discussed. A balanced discussion of the possibilities and limitations for THz stand-off detection is given. http://www.physik.uni-kl.de/beigang