Long-wave Infrared Frequency Combs Based on Quantum Cascade Lasers PDF Download

Author: Tianyi Zeng
Publisher:
ISBN:
Category :
Languages : en
Pages : 105

View

Book Description
Ever since the invention of quantum cascade laser (QCL), the performance and the flexibility in design has made it a desirable source for a wide range of applications, such as trace-chemical sensing, health monitoring, frequency metrology, noninvasive imgaing and infrared countermeasures. The LWIR region (or mid-infrared region), roughly ranging from 2-20 [mu]m, is of particular importance to spectroscopy applications, since many molecular species have their strongest rotational-vibrational absorption bands in that area. Infrared laser spectroscopy began about 40 years ago and has been using a variety of different tunable laser-based sources, particularly lead salt diodes, color center lasers, difference frequency generation and optical parametric oscillators. The large tunabilitiy in the design (lasing frequency, tunability, power, material system, etc.) and the compactness in fabrication and packaging has made QCL an ideal source for laser-based spectroscopy. Traditional spectroscopy systems suffer from problems like large physical dimensions, long data-processing times and spectral resolution restrictions. Therefore the development of a simple, robust, compact and inexpensive optical source/system like QCL frequency combs can largely benefit spectroscopy systems. In the past few years, QCLs have proven to be able to form comb radiation in both LWIR and THz regions. And dual comb spectroscopy has been demonstrated using QCL frequency combs with very short acquisition time ([mu]s). The development of a broadband, high power, narrow linewidth and stable LWIR frequency comb based on quantum cascade laser is the key to realizing such broadband ultrafast spectrometer in the mid-infrared range. This thesis explores the design, fabrication and characterization techniques towards the development of LWIR QCL frequency comb devices for spectroscopic purposes. A complete wet etch epi-up fabrication process is reported, with preliminary results on the dry-etch technique to incorporate dispersion compensation strucutre and epi-down fabricaiton for high power CW mode QCL device. Formation of comb(-like) regime has been observed in two devices, with the Gires-Tournois Interferometer (GTI) mirror providing dispersion from the rear facet. In order to improve the comb performance of these devices, dispersion of the device is measured to provide essential information for the design of chirped top cladding for dispersion compensation. This thesis provides an important step towards the realization of a room temperature, broadband, CW mode LWIR QCL frequency comb device for spectroscopic purposes.

Author: Wolfgang Demtröder
Publisher: Springer
ISBN: 3642538592
Category : Science
Languages : en
Pages : 510

View

Book Description
Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., ultrafast lasers (atto- and femtosecond lasers) and parametric oscillators, coherent matter waves, Doppler-free Fourier spectroscopy with optical frequency combs, interference spectroscopy, quantum optics, the interferometric detection of gravitational waves and still more applications in chemical analysis, medical diagnostics, and engineering.

Author: Dan Botez
Publisher: Cambridge University Press
ISBN: 1108570607
Category : Technology & Engineering
Languages : en
Pages : 552

View

Book Description
Learn how the rapidly expanding area of mid-infrared and terahertz photonics has been revolutionized in this comprehensive overview. State-of-the-art practical applications are supported by real-life examples and expert guidance. Also featuring fundamental theory enabling you to improve performance of both existing and future devices.

Author: Markus Rösch
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description

Author: Jun Ye
Publisher: Springer Science & Business Media
ISBN: 0387237917
Category : Science
Languages : en
Pages : 373

View

Book Description
Over the last few years, there has been a convergence between the fields of ultrafast science, nonlinear optics, optical frequency metrology, and precision laser spectroscopy. These fields have been developing largely independently since the birth of the laser, reaching remarkable levels of performance. On the ultrafast frontier, pulses of only a few cycles long have been produced, while in optical spectroscopy, the precision and resolution have reached one part in Although these two achievements appear to be completely disconnected, advances in nonlinear optics provided the essential link between them. The resulting convergence has enabled unprecedented advances in the control of the electric field of the pulses produced by femtosecond mode-locked lasers. The corresponding spectrum consists of a comb of sharp spectral lines with well-defined frequencies. These new techniques and capabilities are generally known as “femtosecond comb technology. ” They have had dramatic impact on the diverse fields of precision measurement and extreme nonlinear optical physics. The historical background for these developments is provided in the Foreword by two of the pioneers of laser spectroscopy, John Hall and Theodor Hänsch. Indeed the developments described in this book were foreshadowed by Hänsch’s early work in the 1970s when he used picosecond pulses to demonstrate the connection between the time and frequency domains in laser spectroscopy. This work complemented the advances in precision laser stabilization developed by Hall.

Author: Konstantin L. Vodopyanov
Publisher: John Wiley & Sons
ISBN: 1119011973
Category : Technology & Engineering
Languages : en
Pages : 320

View

Book Description
An important guide to the major techniques for generating coherent light in the mid-infrared region of the spectrum Laser-based Mid-infrared Sources and Applications gives a comprehensive overview of the existing methods for generating coherent light in the important yet difficult-to-reach mid-infrared region of the spectrum (2–20 μm) and their applications. The book describes major approaches for mid-infrared light generation including ion-doped solid-state lasers, fiber lasers, semiconductor lasers, and laser sources based on nonlinear optical frequency conversion, and reviews a range of applications: spectral recognition of molecules and trace gas sensing, biomedical and military applications, high-field physics and attoscience, and others. Every chapter starts with the fundamentals for a given technique that enables self-directed study, while extensive references help conduct deeper research. Laser-based Mid-infrared Sources and Applications provides up-to-date information on the state-of the art mid-infrared sources, discusses in detail the advancements made over the last two decades such as microresonators and interband cascade lasers, and explores novel approaches that are currently subjects of intense research such as supercontinuum and frequency combs generation. This important book: • Explains the fundamental principles and major techniques for coherent mid-infrared light generation • Discusses recent advancements and current cutting-edge research in the field • Highlights important biomedical, environmental, and military applications Written for researchers, academics, students, and engineers from different disciplines, the book helps navigate the rapidly expanding field of mid-infrared laser-based technologies.

Author: Dimitris Pavlidis
Publisher: John Wiley & Sons
ISBN: 1119460719
Category : Technology & Engineering
Languages : en
Pages : 580

View

Book Description
An authoritative and comprehensive guide to the devices and applications of Terahertz technology Terahertz (THz) technology relates to applications that span in frequency from a few hundred GHz to more than 1000 GHz. Fundamentals of Terahertz Devices and Applications offers a comprehensive review of the devices and applications of Terahertz technology. With contributions from a range of experts on the topic, this book contains in a single volume an inclusive review of THz devices for signal generation, detection and treatment. Fundamentals of Terahertz Devices and Applications offers an exploration and addresses key categories and aspects of Terahertz Technology such as: sources, detectors, transmission, electronic considerations and applications, optical (photonic) considerations and applications. Worked examplesbased on the contributors extensive experience highlight the chapter material presented. The text is designed for use by novices and professionals who want a better understanding of device operation and use, and is suitable for instructional purposes This important book: Offers the most relevant up-to-date research information and insight into the future developments in the technology Addresses a wide-range of categories and aspects of Terahertz technology Includes material to support courses on Terahertz Technology and more Contains illustrative worked examples Written for researchers, students, and professional engineers, Fundamentals of Terahertz Devices and Applications offers an in-depth exploration of the topic that is designed for both novices and professionals and can be adopted for instructional purposes.

Author: Gerard Marriott
Publisher: Academic Press
ISBN:
Category : Medical
Languages : en
Pages : 584

View

Book Description
The critically acclaimed laboratory standard for more than forty years, Methods in Enzymology is one of the most highly respected publications in the field of biochemistry. Since 1955, each volume has been eagerly awaited, frequently consulted, and praised by researchers and reviewers alike. More than 285 volumes have been published (all of them still in print) and much of the material is relevant even today--truly an essential publication for researchers in all fields of life sciences.

Author: Yang Yang (Ph. D.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 162

View

Book Description
In recent years, there has been growing interest in chip-scale frequency combs, such as micro-resonator combs and semiconductor mode-locked sources. From the mid-infrared to the terahertz regime, it has been shown that quantum cascade lasers (QCLs) are capable of forming a frequency comb state where dispersed cavity modes of the Fabry-Perot cavity are synchronized by third order nonlinearity. With proper dispersion engineering, we have shown that it is possible to create QCL frequency combs at terahertz wavelengths, which possess broadband coverage in a compact package. These QCL combs are particularly attractive as sources for high-sensitivity laser spectroscopy: by using a dual-comb technique, it is possible to perform broadband spectroscopy only using chip-scale components, making it an intriguing candidate for spectroscopic applications in the open field. Moreover, due to the semi-continuous nature of the temporal output from such combs, tracking the instantaneous phase and timing signals of the dual-comb waveform in the time domain becomes feasible. This enables a computational coherent averaging scheme of the dual-comb signal even without external reference. The first part of this thesis describes the development for better THz laser frequency combs. To realize all expectations in the spectroscopy applications using such devices, three main aspects of improvement are highly desired. First, the laser device should have a robust comb state that ideally can operate from device's threshold current, I[subscript th], to its maximum current, I[subscript m]. In addition, the comb states should have a broad spectral coverage: its bandwidth should cover at least an octave span to stabilize its carrier offset. Furthermore, the comb state should have a flexible tunability that allows tuning across the entire free spectral range for gapless sensing. All listed aspects are investigated during the course of this thesis and as a result, a THz QCL device featuring comb state performance over the entire lasing bias range has been demonstrated. Meanwhile, we show that, by compensating cavity dispersion up to higher orders, the comb bandwidth from the full dispersion compensated devices can reach 80 % of its gain bandwidth. One common method to achieve very broadband coverage relies on using the heterogeneous gain media. This comes at the cost of reduced peak gain and hampered temperature performance. Also, engineering the dispersion of such a broadband gain medium becomes extremely challenging, which might not lead to a broader comb coverage albeit its broader gain. However, a unique feature of the metal-metal waveguide is that it is completely agnostic about its bonded gain media. Therefore, it is possible to bond multiple gain media together onto the same chip. The lateral heterogeneous integration scheme is investigated as an alternative method to expand the comb's spectral coverage. We show that using this strategy we can couple the output of combs at vastly different wavelengths without the trade-off with its temperature performance, yet maintain a compact package. Dual-comb spectroscopy allows for high-resolution spectra to be measured over broad bandwidth, but in order to achieve high resolution and acquire low-uncertainty spectroscopic information, the capability for coherent averaging is of the most importance. An essential requirement for coherent averaging is the availability of a phase reference. Usually, this means that the combs' phase and timing errors must be measured and either minimized by stabilization or removed by correction. These hardware-based solutions often require extra electronic or optical components, thus complicates the overall system and further limits the technique's applicability. We demonstrate that it is possible to extract the phase and timing signals of a multiheterodyne spectrum in a completely computational fashion without any extra measurements, which can potentially simplify any dual-comb system. Other works in this thesis include the first proof-of-principle demonstration of THz dual-comb spectroscopy using laser frequency combs, THz hyper-spectral imaging for pharmaceutical compound identification, and the exploratory work on the development of the germanium-on-gallium arsenide platform, a passive on-chip platform showing potential to bridge the THz and mid-infrared regime.

Author: Larry A. Coldren
Publisher: John Wiley & Sons
ISBN: 1118148185
Category : Technology & Engineering
Languages : en
Pages : 752

View

Book Description
Diode Lasers and Photonic Integrated Circuits, Second Edition provides a comprehensive treatment of optical communication technology, its principles and theory, treating students as well as experienced engineers to an in-depth exploration of this field. Diode lasers are still of significant importance in the areas of optical communication, storage, and sensing. Using the the same well received theoretical foundations of the first edition, the Second Edition now introduces timely updates in the technology and in focus of the book. After 15 years of development in the field, this book will offer brand new and updated material on GaN-based and quantum-dot lasers, photonic IC technology, detectors, modulators and SOAs, DVDs and storage, eye diagrams and BER concepts, and DFB lasers. Appendices will also be expanded to include quantum-dot issues and more on the relation between spontaneous emission and gain.