Download or read book Investigation of Ultra broadband Terahertz Time domain Spectroscopy with Terahertz Wave Gas Photonics written by Xiaofei Lu and published by . This book was released on 2011 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultra Broadband THz Time domain Spectroscopy Using Air Photonics written by Xiaoyu Guo and published by . This book was released on 2009 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Terahertz Metrology written by Mira Naftaly and published by Artech House. This book was released on 2015-01-01 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Introduction to THz Wave Photonics written by Xi-Cheng Zhang and published by Springer Science & Business Media. This book was released on 2009-12-01 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Ultra broadband Terahertz Spectroscopy with Terahertz Air Photonics written by Francesco D'Angelo and published by . This book was released on 2016 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: "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.

Download or read book Terahertz Liquid Photonics written by Xi-cheng Zhang and published by World Scientific. This book was released on 2023-07-26 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Terahertz Spectroscopy written by Jamal Uddin and published by BoD – Books on Demand. This book was released on 2017-03-13 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: The terahertz regime of the electromagnetic spectrum was largely unexplored due to the lack of technology needed to generate and detect the radiation. However, in the last couple of decades, there has been a dramatic increase in tools needed to harness the radiation. This remarkable progress made in the development of terahertz sources, components, and detectors has resulted in an ever-increasing inquisitiveness of the applications of terahertz technology in a wide range of fields including medicine, pharmaceuticals, security, sensing, and quality assurance. This book, Terahertz Spectroscopy - A Cutting Edge Technology, presents an overview of the recent advances in terahertz technology and their application in a vast array of fields. The scientists and students are encouraged to read and share the content of this volume. The book also provides a good starting point for researchers who are new to the terahertz regime. The various chapters of the book have been written by renowned scientists in different parts of the world who are at the forefront of terahertz research fields. It is our (InTech publisher, editor, and authors) hope that this book will enhance knowledge and stimulate more interest and future research in terahertz technology.

Download or read book Optical to Terahertz Engineering written by Arijit Saha and published by Springer Nature. This book was released on 2023-03-31 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights advances in the field of THz engineering along with limitations of radio frequency (RF) technology. All engineering applications have been designed to operate over a specific frequency or wavelength range in electromagnetic spectrum. In recent years, the unexplored domain of THz range of electromagnetic spectrum has paved the way for terahertz technology due to its nonionizing nature and sensitivity to water content. A wide range of applications with THz techniques such as terahertz time-domain spectroscopy (THz-TDS), biological, medical and pharmaceutical sciences, explosives inspection, information and communication technology (ICT) sector and many more, have potential to be the technology of future. Different designing aspects and evolving application areas are addressed to enrich the technical knowledge of readers. This book provides an overview of state of the art in terms of research and industrial progress in THz spectrum.

Download or read book Terahertz Time Domain Spectroscopy Systems for Fundamental and Industrial Applications written by Michael Theuer and published by Cuvillier Verlag. This book was released on 2009-07-27 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Intense Terahertz Excitation of Semiconductors written by Sergey Ganichev and published by OUP Oxford. This book was released on 2005-12-15 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intense Terahertz Excitation of Semiconductors presents the first comprehensive treatment of high-power terahertz applications to semiconductors and low-dimensional semiconductor structures. Terahertz properties of semiconductors are in the center of scientific activities because of the need of high-speed electronics. This research monograph brigdes the gap between microwave physics and photonics. It focuses on a core topic of semiconductor physics providing a full description of the state of the art of the field. _ The reader is introduced to new physical phenomena which occur in the terahertz frequency range at the transition from semi-classical physics with a classical field amplitude to the fully quantized limit with photons. The book covers a wide range of optical, optoelectronic, and nonlinear transport processes, presenting experimental results, clearly visualizing models and basic theories. Background information for future work and exhaustive references of current literature are given. A particularly valuable feature is through the discussion of various technical aspects of the terahertz range like the generation of high-power coherent radiation, optical components, instrumentation, and detection schemes of short intense radiation impulses. The book complements, for the first time in form of a monograph, previous books on infrared physics which dealt with low-power optical and opto-electronic processes. It will be useful not only to scientists but also to advanced students who are interested in terahertz research.

Download or read book Sensing with Terahertz Radiation written by Daniel Mittleman and published by Springer. This book was released on 2013-02-26 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this book is two-fold. First, the various different methods of accessing the THz range are discussed, with a view to convince the reader that there have been qualitative and significant improvements over older, more conventional techniques. The text makes it clear that these improvements enable practical "real-world" applications of THz technology, in a manner which would not have been possible before. Second, the demonstrations and feasibility tests described serve as compelling evidence of the utility of such devices. Due to the unique characteristics of THz radiation and its interaction with materials, these devices have substantial advantages over other competing technologies in a number of different areas.

Download or read book Handbook of Terahertz Technology for Imaging Sensing and Communications written by D Saeedkia and published by Elsevier. This book was released on 2013-01-16 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recent development of easy-to-use sources and detectors of terahertz radiation has enabled growth in applications of terahertz (Thz) imaging and sensing. This vastly adaptable technology offers great potential across a wide range of areas, and the Handbook of terahertz technology for imaging, sensing and communications explores the fundamental principles, important developments and key applications emerging in this exciting field. Part one provides an authoritative introduction to the fundamentals of terahertz technology for imaging, sensing and communications. The generation, detection and emission of waves are discussed alongside fundamental aspects of surface plasmon polaritons, terahertz near-field imaging and sensing, room temperature terahertz detectors and terahertz wireless communications. Part two goes on to discuss recent progress and such novel techniques in terahertz technology as terahertz bio-sensing, array imagers, and resonant field enhancement of terahertz waves. Fiber-coupled time-domain spectroscopy systems (THz-TDS), terahertz photomixer systems, terahertz nanotechnology, frequency metrology and semiconductor material development for terahertz applications are all reviewed. Finally, applications of terahertz technology are explored in part three, including applications in tomographic imaging and material spectroscopy, art conservation, and the aerospace, wood products, semiconductor and pharmaceutical industries. With its distinguished editor and international team of expert contributors, the Handbook of terahertz technology for imaging, sensing and communications is an authoritative guide to the field for laser engineers, manufacturers of sensing devices and imaging equipment, security companies, the military, professionals working in process monitoring, and academics interested in this field. Examines techniques for the generation and detection of terahertz waves Discusses material development for terahertz applications Explores applications in tomographic imaging, art conservation and the pharmaceutical and aerospace industries

Download or read book Enhanced Polarisation Control and Extreme Electric Fields written by Connor Devyn William Mosley and published by Springer Nature. This book was released on 2021-03-25 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports advances in terahertz time-domain spectroscopy, relating to the development of new techniques and components that enhance the experimentalist’s control over the terahertz polarisation state produced by photoconductive emitters. It describes how utilising the dynamic magnetoelectric response at THz frequencies, in the form of electromagnons, can probe material properties at a transition between two magnetically ordered phases. Additionally, preliminary investigations into the properties of materials exposed to extreme terahertz optical electric fields are reported. The work presented in this thesis may have immediate impacts on the study of anisotropic media at THz frequencies, with photoconductive emitters and detectors being the most commonly used components for commercially available terahertz spectroscopy and imaging systems, and by providing a new way to study the nature of magnetic phase transitions in multiferroics. In the longer term the increased understanding of multiferroics yielded by ultrafast spectroscopic methods, including terahertz time-domain spectroscopy, may help develop new magnetoelectric and multiferroic materials for applications such as spintronics.

Download or read book Terahertz Time Domain Spectroscopy of Low Dimensional Materials and Photonic Structures written by Chen Xia and published by . This book was released on 2013 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Terahertz (THz), the frequency region that bridges the gap between the radio and optical frequencies in the electromagnetic spectrum, is of both scientific and technological importance. Its broad applications, however, have been limited by the availability of bright sources and sensitive detectors. The invention of modelocked femtosecond lasers has made possible the generation and detection of electromagnetic transients on the picosecond to sub-picosecond time scale, which correspond to broadband coherent radiation up to a few or 10{u2019}s THz. This time-domain technique has had a significant impact on spectroscopy, imaging and sensing. While detectors and emitters have been the main interest in the development of THz technology, other components such as modulators, reflectors and filters are also of importance. In Chapter 2 we apply THz transmission spectroscopy to characterize polymeric materials and nano-composites. We demonstrate the design and fabrication of THz mirrors based on one-dimensional photonic crystals consisting thermoplastic polymers and BaTiO3 nanoparticles. Stop bands have been achieved in the THz region, and the results agree well with the prediction of the transfer matrix method. The main focus of this thesis is to study charge transport and carrier dynamics in low dimensional materials using THz time-domain spectroscopy. In contrast to conventional transport measurements, where electrical contacts are required, the THz method based on freely propagating electromagnetic transients can probe the electronic transport in a contactless fashion. In Chapter 3 we investigate highly oriented pyrolytic graphite (HOPG) using the THz emission spectroscopy. The direction, spectrum, polarization and dynamics of the emitted THz radiation from graphite upon ultrafast photoexcitation reveal the emission mechanism as well as the out-of-plane transport properties of graphite. In Chapter 4 metal phthalocyanines have been investigated by the optical pump/THz probe technique. Disc-like phthalocyanine molecules self-assemble into columns and form quasi-1D conduction channels for efficient charge transport. With appropriate side groups the material can have both crystalline and liquid crystalline phases. The photoconductivity spectrum, its dependence on the pump-probe delay time and sample temperature suggest the mechanism of as well as the influence of crystallinity on the photoconductivity in metal phthalocyanines.

Download or read book Springer Handbook of Lasers and Optics written by Frank Träger and published by Springer Science & Business Media. This book was released on 2012-05-05 with total page 1704 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new edition features numerous updates and additions. Especially 4 new chapters on Fiber Optics, Integrated Optics, Frequency Combs and Interferometry reflect the changes since the first edition. In addition, major complete updates for the chapters: Optical Materials and Their Properties, Optical Detectors, Nanooptics, and Optics far Beyond the Diffraction Limit. Features Contains over 1000 two-color illustrations. Includes over 120 comprehensive tables with properties of optical materials and light sources. Emphasizes physical concepts over extensive mathematical derivations. Chapters with summaries, detailed index Delivers a wealth of up-to-date references.

Download or read book Terahertz Optoelectronics written by Kiyomi Sakai and published by Springer Science & Business Media. This book was released on 2005-06-13 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents recent and important developments in the field of terahertz radiation, with a particular focus on pulsed terahertz radiation. Situated in the gap between electronics and optics, the terahertz frequency range of the electro-magnetic spectrum has long been neglected by scientists and engineers due to a lack of efficient and affordable terahertz sources and detectors. The advent of femtosecond lasers in the 1980s and photoconductive switches in 1984 have made the terahertz gap accessible, while at the same time advances in electronics and optics have made it narrower. Research activities in terahertz frequencies have intensified dramatically since that time, funding has increased by a factor of 100 in the last decade. The reviews by leading experts are of interest to researchers and engineers as well as advanced students.

Download or read book Terahertz Time domain Spectroscopy of Two dimensional Electron Gasses at High Magnetic Fields written by Jeremy A. Curtis and published by . This book was released on 2016 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation covers two projects that were in the logical path to studying decoherence in a high mobility GaAs two-dimensional electron gas at high magnetic fields. The first project is the ultrafast non-degenerate pump-probe spectroscopic study of bulk GaAs in the Split Florida Helix at the National High Magnetic Field Laboratory at Florida State University. This project was undertaken as a proof of concept that ultrafast optics could be done in the Split Florida Helix so that we might study a high mobility two dimensional electron gas using THz time-domain spectroscopy at high magnetic fields, which is a much more complicated measurement than the pump-probe discussed here. This demonstration was a success. We completed the first ultrafast optical study of any kind in the Florida Split Helix. We collected differential reflection data from this bulk sample that exhibited electronic and oscillatory components. These components were treated independently in the analysis by treating the electronic dynamics with a four level approximation. The electronic transition rates were extracted and agreed well with published values. This agreement is a demonstration that the spectrometer functioned as desired. The oscillatory response was found to be a result of the emission of coherent phonons upon electronic transition between the four levels. The frequency of the oscillatory response was extracted and agreed well with the theoretical value. The second project is the study of the temperature dependence of the cyclotron decay lifetimes in a Landau quantized GaAs high mobility two dimensional electron gas using THz time-domain spectroscopy at relatively low magnetic field (1.25 T). We find that the cyclotron decay lifetimes decrease monotonically with increasing temperature from 0.4 K to 100 K and that the primary pulse amplitudes increase from 0.4 K to 1.2 K, saturates above 1.2 K up to 50 K, and decreases rapidly above 50 K. We attribute this rapid drop in amplitude above 50 K as well as the high temperature behavior of the cyclotron resonance decay times to polar optical phonon scattering. We find that the dissipative component of the measured cyclotron decay lifetimes can not be well approximated by a DC scattering lifetime model, which includes polar optical phonon scattering, remote ionized impurity scattering, acoustic deformation potential scattering, and piezo-electric scattering. This discrepancy is due to the entirely different distribution of the Fermi surface resulting from the Landau quantization of the quantum well's states. This project demonstrates the type of measurements we would like to conduct at higher magnetic fields using more broadband THz sources. Future work is finally discussed, which outlines the construction and demonstration of a custom ultra broadband THz time-domain spectrometer for use in the Florida Split Helix. The data collected is not of sufficient quality to extract physical meaning due to its decreased signal to noise and bandwidth relative to the test of the system through the magnet without sample or windows at 0 T and 300 K, which demonstrated the generation and detection of 15 THz of usable bandwidth. This reduction in signal to noise and bandwidth is due to clipping the THz beam on the magnet aperture. Future measurements will use optically clear windows that are also transparent in the THz so that alignment of the THz beam may be done with an optical beam. While the original goal was an extension of the temperature dependent measurements described in the previous paragraph at much higher applied magnetic field strength, the design, construction, and demonstration of the system without sample or windows as well as the data set collected through a high mobility GaAs two dimensional electron gas at 25 T and 15 K constitutes the first THz time-domain measurements conducted in the Florida Split Helix.