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Coherent Tunable Thz Fir Radiation Sources
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Book Synopsis Coherent Tunable Thz-FIR Radiation Sources by :
Download or read book Coherent Tunable Thz-FIR Radiation Sources written by and published by . This book was released on 1999 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: As described by the title the grant funds were used to support a project whose primary goal was the development of tunable coherent sources for the THz-FIR region of the spectrum. The THz or more generally the FIR extends from 0.3 x 10(exp 12) (0.3THz) to 30 x 10(exp 12) (30THz) or alternatively from a wavelength of 1 mm down to a wavelength of 10 gm. It is a range of the spectrum that has been a long standing challenge. Microwave technology which has been extraordinarily successful at wavelengths longer than 1 mm and classical and quantum optical techniques which are extremely effective in the visible, near and mid infrared regions of the spectrum encounter fundamental challenges when extended (respectively) to longer or shorter wavelengths. Continued interest in "opening up" and exploiting the FIR region of the spectrum is based on the scientific questions which in part demand an access to the THz-FIR spectral range. These extend from atmospheric and biophysics to plasma physics and radio astronomy. Important technological applications also exist. Among the examples would be radar modeling, characterization of the response of near millimeter wave (NMMW) systems and the potential for short range high resolution radar. The immediate scientific and engineering goals of the project supported by the equipment grant provide a source that is tunable, narrow band and provides sufficient power for spectroscopic investigations. In the longer term a compact conveniently packaged sources and potential and requirements needed to reach higher power operation are of interest. The grating couples the beam with the electromagnetic field provides distributed feedback which reacts back on the beam and in turn leads to bunching of the beam. The density bunches produce the coherent operation.
Book Synopsis Development and Application of Tunable Coherent Terahertz Radiation Source by :
Download or read book Development and Application of Tunable Coherent Terahertz Radiation Source written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Generation and Detection of Coherent Tunable Terahertz Radiation in Free Space by : Aniruddha S. Weling
Download or read book Generation and Detection of Coherent Tunable Terahertz Radiation in Free Space written by Aniruddha S. Weling and published by . This book was released on 1996 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Introduction to THz Wave Photonics by : Xi-Cheng Zhang
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.
Book Synopsis Terahertz and Mid Infrared Radiation by : Mauro F. Pereira
Download or read book Terahertz and Mid Infrared Radiation written by Mauro F. Pereira and published by Springer. This book was released on 2011-02-26 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Terahertz (THz) and Mid-Infrared (MIR) radiation (TERA-MIR) can be transmitted through nearly any material without causing biological harm. Novel and rapid methods of detection can be created with devices operation in these spectral ranges allowing scanning for weapons, detecting hidden explosives (including plastic landmines), controlling the quality of food and a host of other exciting applications. This book focuses on mathematical and physical aspects of the field, on unifying these two spectral domains (THz and MIR) with regard to common sources, detectors, materials and applications, and on key interdisciplinary topics. The main THz and MIR source is the quantum cascade laser (QCL). Thus significant attention is paid to the challenge of turning this advanced technology into affordable commercial devices so as to exploit its enormous potential. However other alternatives to THz QCLs are also presented, e.g. sub-terahertz imaging from avalanching GaAs bipolar transistors, Josephson junctions as THz sources, semiconductor materials for pulsed THz sources, superconducting THz electronics with Josephson vortices. In summary this book delivers a global picture of the state of the art in TERA-MIR generation, detection and applications.
Book Synopsis Coherent Thz Sources: Present Status and the Potential of New Approaches by :
Download or read book Coherent Thz Sources: Present Status and the Potential of New Approaches written by and published by . This book was released on 1995 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main aim of this report is to give a state of the art view of the different approaches toward the realisation of THz sources. The report concentrates on semiconductor based sources which can be integrated in MMICs. At the lower end of the spectrum in the inn to 700 GHz range several commercially available semiconductor sources operate at room temperature. Field effect transistors and oscillators such as IMPATT diodes or Gunn oscillators have reached frequencies between 100 and 200 GHz with power levels well above the 100 mW range. Due to the advances in semiconductor growth techniques new concepts for the realisation of THz sources can be persued. The most interesting concept is the Voltage driven Bloch oscillator, which would lead to a coherent and widely tuneable source. A second concept is the intersubband laser already demonstrated for infrared frequencies. A quite promising approach is the current induced generation of collective excitations - plasma waves - to generate tuneable radiation in the THz region. This concept combines classical methods of carrier bunching with confinement concepts and the shaping of bandstructures. Finally THz radiation generated by short pulses offers also a new source with a wide frequency range for coherent spectroscopy. (AN).
Book Synopsis Development and Spectroscopic Applications of a Coherent, Narrowband Radiation Source Tunable from 0.1 to 14 THz by : Christa Haase
Download or read book Development and Spectroscopic Applications of a Coherent, Narrowband Radiation Source Tunable from 0.1 to 14 THz written by Christa Haase and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A New Tunable Source for the FIR-THz Spectral Region by :
Download or read book A New Tunable Source for the FIR-THz Spectral Region written by and published by . This book was released on 2003 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Grating Coupled Oscillator (GCO) has the potential to be a practical coherent source for far-infrared/terahertz (FIR/THz) research and applications. The GCO, simply an electron beam skimming a diffraction grating, has inherently many desirable features: continuously tunable from microwave to visible, continuous wave at room temperature, excellent spatial and spectral quality, stable, compact, robust, simple, and economical. Alternative sources (e.g. solid-state, short-pulse optical switches, free-electron lasers, and blackbody) do not share these characteristics. The GCO emits radiation by the Smith-Purcell effect: diffraction of the electron wake field. Spontaneous Smith-Purcell emission is easily generated. The difficulty lies in developing enough feedback in an open resonator (i.e. the grating) to produce sufficient coherent power without resorting to an enclosed resonator cavity, thereby limiting the tuning range. The aim of this project was to understand the beam-wave gain process though parametric studies in enough detail to pinpoint optimum resonator designs by which the GCO could operate well into the terahertz regime. Theoretical and experimental studies of the GCO indicate a three-wave interaction. Beating between the waves is observed in the sub-threshold radiant power with a cube root dependence on the current. Both gain and loss are greater than predicted. Observed parametric power dependence necessitated the development of a self-consistent field theory. The Grating Horn resonator magnified GCO intensity by 100 times. Many orders of magnitude further increase in power are predicted with the novel Lossless Resonator concept. GCO and Smith-Purcell experiments with moderate and high energy electron beams corroborate the underlying GCO theory. A list of related publications is included.
Book Synopsis Interaction of Terahertz Radiation with Semiconductor Lasers by : Jared Ombiro Gwaro
Download or read book Interaction of Terahertz Radiation with Semiconductor Lasers written by Jared Ombiro Gwaro and published by Cuvillier Verlag. This book was released on 2019-06-18 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Terahertz (THz) technology bears great potential in spectroscopy, imaging, material science, security screening and high-speed wireless communication. However, the generation of intensive, directional THz radiation has been difficult and the THz frequency range has long been considered the last final frontier of the electromagnetic spectrum. Recent advancement in optoelectronic terahertz generation techniques and high power electronic sources has helped to bridge the THz gap and has opened up a wealth of new applications for THz technology. However, there is still a major technical limitation in developing THz systems for mass markets, mainly due to the cost of THz hardware components including sources and detectors. In this regard, we investigated the use of semiconductor diode lasers as THz detectors as well as excitation sources for photomixers for THz generation. For THz detection, we investigated the interaction of semiconductor lasers with THz radiation. Intense THz radiation from different sources and at various frequencies was injected into the laser diode. The laser diode was operated in Littman configuration to ensure clean single mode operation in the near infrared. The charge carrier system in the semiconductor was expected to interact with the injected THz radiation and introduce nonlinear frequency mixing. This nonlinear mixing was to induce sidebands in the near infrared optical spectra and was to be analyzed with an optical spectrum analyzer. This may lead to the demonstration of a simple, cost effective and compact room temperature THz spectrometer since the distance between the emission line and the sidebands equals the incident THz frequency. Unfortunatly, due to unprecedented challenges the interaction of THz radiation with diode laser experiment was not successful. Another approach was to demonstrate a compact and cost effective THz source based on monolithic distributed Bragg reflector diode laser emitting two frequencies simulteneously. We successfully demonstrated 300 GHz continuous wave THz radiation, with fiber coupled ion implanted photoconductive antennas used as photomixing devices. The generated THz radiation was tunable via temperature adjustments and current injection. This approach provided a coarse tuning in the range of 286 GHz to 320 GHz. We successfully demonstrated its potential use in non-destructive plant moisture measurements of a leaf induced to drought stresses and for moisture monitoring in drying process of pieces of paper. Due to the fact that the tuning of the developed THz source was coarse, we proposed the use of a new diode which was electrically tunable for fine tuning of the generated THz frequency. The new diode offers optical beat signal adjustments via carrier injection to the DBR section using micro resistor heater integrated on top of the DBR segment. The optical beat tuning via carrier injection was fast and offers tuning which should be free from mode hopping. The injection current to the resistor heater can be adjusted between 0 to 350 mA, an optical beat adjustment of between 100 GHz-300 GHz was realized. This bandwidth was only limited with the overlap of the two modes at higher heater currents of 250 mA to 350 mA. THz radiation emission via photomixing in the range 100 GHz-300 GHz was successfully demonstrated, these results were in good agreement with the optical beat signal measurements. Finally, a simple spectrometer suitable for THz metrology measurements such as thickness determination of Polyethylene sample (PE) was realized and also its application in THz spectroscopy was demonstrated by the determination of the spectroscopic transmission characteristics of a THz filter. In summary, two compact THz sources emitting at 300 GHz were successfully demonstrated and this was a major milestone towards development of compact and cost effective THz system for mass market application.
Book Synopsis A Stable, Tunable Source of Coherent XUV Radiation for Atomic Spectroscopy Below 100 Nm by : David Gordon Cooper
Download or read book A Stable, Tunable Source of Coherent XUV Radiation for Atomic Spectroscopy Below 100 Nm written by David Gordon Cooper and published by . This book was released on 1988 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Handbook of High-resolution Spectroscopy by : Martin Quack
Download or read book Handbook of High-resolution Spectroscopy written by Martin Quack and published by John Wiley & Sons. This book was released on 2011-09-26 with total page 2236 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of High-Resolution Spectroscopy has been considerably extended and even redefined in some areas. Combining the knowledge of spectroscopy, laser technology, chemical computation, and experiments, Handbook of High-Resolution Spectroscopy provides a comprehensive survey of the whole field as it presents itself today, with emphasis on the recent developments. This essential handbook for advanced research students, graduate students, and researchers takes a systematic approach through the range of wavelengths and includes the latest advances in experiment and theory that will help and guide future applications. The first comprehensive survey in high-resolution molecular spectroscopy for over 15 years Brings together the knowledge of spectroscopy, laser technology, chemical computation and experiments Brings the reader up-to-date with the many advances that have been made in recent times Takes the reader through the range of wavelengths, covering all possible techniques such as Microwave Spectroscopy, Infrared Spectroscopy, Raman Spectroscopy, VIS, UV and VUV Combines theoretical, computational and experimental aspects Has numerous applications in a wide range of scientific domains Edited by two leaders in this field Provides an overview of rotational, vibration, electronic and photoelectron spectroscopy Volume 1 - Introduction: Fundamentals of Molecular Spectroscopy Volume 2 - High-Resolution Molecular Spectroscopy: Methods and Results Volume 3 - Special Methods & Applications
Book Synopsis Mid-Infrared Coherent Sources and Applications by : Majid Ebrahim-Zadeh
Download or read book Mid-Infrared Coherent Sources and Applications written by Majid Ebrahim-Zadeh and published by Springer Science & Business Media. This book was released on 2008-01-02 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering fundamental principles and the state of the art, this is a collection of reviews from experts in mid-infrared (mid-IR) coherent sources. Among the sources covered are optical parametric oscillators, difference frequency generators, and the most recent broadband crystalline, quantum cascade, and fiber lasers. The authors show how advances in mid-IR science and technology make these sources indispensable for a variety of applications.
Book Synopsis Terahertz and Mid Infrared Radiation: Detection of Explosives and CBRN (Using Terahertz) by : Mauro F. Pereira
Download or read book Terahertz and Mid Infrared Radiation: Detection of Explosives and CBRN (Using Terahertz) written by Mauro F. Pereira and published by Springer. This book was released on 2014-03-10 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reader will find here a timely update on new THz sources and detection schemes as well as concrete applications to the detection of Explosives and CBRN. Included is a method to identify hidden RDX-based explosives (pure and plastic ones) in the frequency domain study by Fourier Transformation, which has been complemented by the demonstration of improvement of the quality of the images captured commercially available THz passive cameras. The presented examples show large potential for the detection of small hidden objects at long distances (6-10 m). Complementing the results in the short-wavelength range, laser spectroscopy with a mid-infrared, room temperature, continuous wave, DFB laser diode and high performance DFB QCL have been demonstrated to offer excellent enabling sensor technologies for environmental monitoring, medical diagnostics, industrial and security applications. From the new source point of view a number of systems have been presented - From superconductors to semiconductors, e.g. Detection of Terahertz Waves from Superconducting Bi2Sr2CaCu2O8+δ Intrinsic Josephson Junctions. The quest for a compact room temperature THz source and the recent advances in high power mid-IR QCLs lead to the development of a semiconductor THz source based on intracavity difference frequency generation. Furthermore, alternative electrically pumped THz sources based on the high emission efficiency predicted for polaritonic states in the ultra-strong coupling regime led to the demonstration of electroluminescent devices. Finally, antipolaritons in dispersive media were discussed and different aspects of the interaction of THz radiation with biomatter were presented.
Book Synopsis Generation of Narrow-Band Coherent Tunable Terahertz Radiation Using a Laser-Modulated Electron Beam by :
Download or read book Generation of Narrow-Band Coherent Tunable Terahertz Radiation Using a Laser-Modulated Electron Beam written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis New Widely Tunable Room-Temperature Terahertz Coherent Sources by :
Download or read book New Widely Tunable Room-Temperature Terahertz Coherent Sources written by and published by . This book was released on 2008 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this proposal was to develop a new type of THz semiconductor sources that are injection-pumped, efficient, compact, narrowband, tunable, and can operate at room temperature. The proposed device was a mid-infrared InGaAs/AlInAs Quantum Cascade Laser (QCLs) with the waveguide core containing a multi-functional coupled-quantum-well active region that supports both laser action in the mid-infrared and THz generation due to resonant coherent beating of two laser modes. During the course of the work a path was also found to substantially improve the temperature performance and directionality of conventional THz QCLs in which an electronic transition is used for the direct generation of THz radiation. The following was accomplished: first room temperature operation of an elctrically pumped quantum cascade laser based THz source, using intra-cavity nonlinear optics; record operating temperature (180K) of a conventional THz Quantum Cascade Laser, using a copper double metal waveguide for low loss; surface emitting THz QCLs with low beam divergence.
Book Synopsis Ultrashort Pulse Lasers and Ultrafast Phenomena by : Takayoshi Kobayashi
Download or read book Ultrashort Pulse Lasers and Ultrafast Phenomena written by Takayoshi Kobayashi and published by CRC Press. This book was released on 2023-03-21 with total page 1255 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the basic physical principles of techniques to generate and ultrashort pulse lasers and applications to ultrafast spectroscopy of various materials covering chemical molecular compounds, solid-state materials, exotic novel materials including topological materials, biological molecules and bio- and synthetic polymers. It introduces non-linear optics which provides the basics of generation and measurement of pulses and application examples of ultrafast spectroscopy to solid state physics. Also it provide not only material properties but also material processing procedures. The book describes also details of the world shortest visible laser and DUV lasers developed by the author’s group. It is composed of the following 12 Sections: The special features of this book is that it is written by a single author with a few collaborators in a systematic way. Hence it provides a comprehensive and systematic description of the research field of ultrashort pulse lasers and ultrafast spectroscopy. Generation of ultrashort pulses in deep ultraviolet to near infrared Generation of ultrashort pulses in terahertz Carrier envelope phase (CEP) Simple NLO processes with a few colors Multi-color involved NLO processes Multi-color ultrashort pulse generation NLO materials NLO processes in time-resolved spectroscopy Low dimension materials Conductors and superconductors Chemical reactions and material processing Photobiological reactions
Book Synopsis Sensing with Terahertz Radiation by : Daniel Mittleman
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.
