Novel Terahertz And Nanophotonic Lasers

In this thesis, we will explore numerical modeling and fabrication of laser sources. First, we demonstrate and distinguish experimentally the existence of special type of Fano resonances at k~~0 in a macroscopic two-dimensional photonic crystal slab. We fabricate a square lattice array of holes in silicon nitride layer and perform an angular resolved spectral analysis of the various Fano resonances. We elucidate their radiation behavior using temporal coupled-mode theory and symmetry considerations. The unique simplicity of this system whereby an ultra-long lifetime delocalized electromagnetic field can exist above the surface and consequently easily interact with added matter, provides exciting new opportunities for the study of light and matter interaction. However, we confirmed that achievable quality factor (Q) is limited by fabrication imperfection. Therefore, in the second part, we present an extensive fabrication optimization process, through which we established improved Q by a factor of three. Lastly, we report a comprehensive theoretical analysis and new experimental data of high-pressure (> 1 Torr) lasing action in optically-pumped far-infrared (OPFIR) lasers. No previous models could satisfactorily capture high-pressure operation because of the growing role of excited vibrational levels. Without these additional excited vibrational levels, molecules are artificially trapped in lower energy vibrational levels. This, in turn, prematurely triggers the so-called vibrational bottleneck and quenches the lasing action at low pressures in the previous models. Even though the high-pressure behavior can be more realistically modeled by including numerous excited vibrational levels, it would dramatically increase the computation time, and more importantly, the rate constants connecting all these levels are unknown. We propose a new model with an expandable pool which embodies 120 excited vibrational levels. Moreover, the knowledge of state-to-state rates among the excited vibrational levels is unnecessary in the proposed new model since the net rate related to the expandable level can be found by equilibrium conditions. Together with a detailed calculation of the pump rate and the wall collision rate, our model qualitatively and quantitatively reproduces experimentally measured high-pressure behavior. The model can be universally used for any OPFIR gas laser system. Thus, our work puts forward a theoretical formalism that could enable the advancement of compact terahertz radiation sources.

The book presents information about Terahertz science, Terahertz photodetectors and Terahertz Lasers. A special emphasis is given to room temperature operation of long wavelength photodetectors based on novel quantum dots (Centered Defect Spherical Quantum Dots). Moreover, a complete analysis of systems based on Quantum Cascade structures to detect far infrared wavelengths is provided. Finally, the book presents Terahertz laser principles considering multi-color lasers in this range of wavelengths. Written as a background for graduate students in the Optics field.

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

In this book the authors present several examples of techniques used to overcome the Abby diffraction limit using flat and 3D diffractive optical elements, photonic crystal lenses, photonic jets, and surface plasmon diffractive optics. The structures discussed can be used in the microwave and THz range and also as scaled models for optical frequencies. Such nano-optical microlenses can be integrated, for example, into existing semiconductor heterostructure platforms for next-generation optoelectronic applications. Chapter 1 considers flat diffractive lenses and innovative 3D radiating structures including a conical millimeter-wave Fresnel zone plate (FZP) lens proposed for subwavelength focusing. In chapter 2 the subwavelength focusing properties of diffractive photonic crystal lenses are considered and it is shown that at least three different types of photonic crystal lens are possible. With the aim of achieving subwavelength focusing, in chapter 3 an alternative mechanism to produce photonic jets at Terahertz frequencies (terajets) using 3D dielectric particles of arbitrary size (cuboids) is considered. A scheme to create a 2D “teraknife” using dielectric rods is also discussed. In the final chapter the successful adaptation of free-space 3D binary phase-reversal conical FZPs for operation on surface plasmon-polariton (SPP) waves demonstrates that analogues of Fourier diffractive components can be developed for in-plane SPP 3D optics. Review ing theory, modelling and experiment, this book will be a valuable resource for students and researchers working on nanophotonics and sub-wavelength focusing and imaging.

This book provides a cutting-edge research overview on the latest developments in the field of Optics and Photonics. All chapters are authored by the pioneers in their field and will cover the developments in Quantum Photonics, Optical properties of 2D Materials, Optical Sensors, Organic Opto-electronics, Nanophotonics, Metamaterials, Plasmonics, Quantum Cascade lasers, LEDs, Biophotonics and biomedical photonics and spectroscopy.

This book offers the readers an opportunity to acquire the concepts of artificial intelligence (AI) enabled sub-THz systems for novel applications in the biomedical field. The readers will also be inspired to contextualize these applications for solving real life problems such as non-invasive glucose monitoring systems, cancer detection and dental imaging. The introductory section of this book focuses on existing technologies for radio frequency and infrared sensing in biomedical applications, and their limited use in sensing applications, as well as the advantages of using THz technology in this context. This is followed by a detailed comparative analysis of THz electronics technology and other conventional electro optic THz setups highlighting the superior efficiency, affordability and portability of electronics-based THz systems. The book also discusses electronic sub-THz measurement systems for different biomedical applications. The chapters elucidate two major applications where sub-THz provides an edge over existing state of the art techniques used for non-invasive measurement of blood glucose levels and intraoperative assessment of tumor margins. There is a detailed articulation of an application of leveraging machine learning for measurement systems for non-invasive glucose concentration measurement. This helps the reader relate to the output in a more user-friendly format and understand the possible use cases in a more lucid manner. The book is intended to help the reader learn how to build tissue phantoms and characterize them at sub-THz frequencies in order to test the measurement systems. Towards the end of the book, a brief introduction to system automation for biomedical imaging is provided as well for quick analysis of the data. The book will empower the reader to understand and appreciate the immense possibilities of using electronic THz systems in the biomedical field, creating gateways for fueling further research in this area.​

Fundamentals and Applications of Nonlinear Nanophotonics includes key concepts of nonlinear nanophotonics, computational and modeling techniques to design these materials, and the latest advances. This book addresses the scientific literature on nanophotonics while most existing books focus almost exclusively on the linear aspects of light-matter interaction at the nanoscale. Sections cover nonlinear optics of sub-wavelength photonic nanostructured materials, review nonlinear optics of bound-states in the continuum, nonlinear optics of chiral plasmonic metasurfaces, nonlinear hyperbolic nanomaterials, nonlinear topological photonics, plasmonic lattice solitons, and more. This book is suitable for academics and industry professionals working in the discipline of materials science, engineering and nanotechnology. Discusses advances in nonlinear optics research such as plasmonics, topological photonics and emerging materials Reviews the latest computational methods to model and design nonlinear photonic materials Introduces key principles of advanced concepts in nonlinear optics of bound-states in a continuum and symmetries in nonlinear nano-optics

This book is a collection of the works of leading experts worldwide in the rapidly developing fields of plasmonics and metamaterials. These developments are promising to revolutionize ways of generating, controlling and processing light in the nanoscale. The technological applications range from nano-lasers to optical nano-waveguides to artificial media with unusual and exotic optical properties unattainable in natural materials. The volume cuts across all relevant disciplines and covers experiments, measurements, fabrication, physical and mathematical analysis, as well as computer simulation.

This book provides a cutting-edge research overview on the latest developments in the field of Optics and Photonics. All chapters are authored by the pioneers in their field and will cover the developments in Quantum Photonics, Optical properties of 2D Materials, Optical Sensors, Organic Opto-electronics, Nanophotonics, Metamaterials, Plasmonics, Quantum Cascade lasers, LEDs, Biophotonics and biomedical photonics and spectroscopy.

Developed from the authors' classroom-tested material, Semiconductor Laser Theory takes a semiclassical approach to teaching the principles, structure, and applications of semiconductor lasers. Designed for graduate students in physics, electrical engineering, and materials science, the text covers many recent developments, including diode lasers u