Discover how mid-infrared and terahertz photonics has been revolutionized in this comprehensive overview of state-of-the art quantum cascade lasers (QCLs). Combining real-world examples with expert guidance, it provides a thorough treatment of practical applications, including high-power continuous-wave QCLs, frequency-comb devices, quantum-electronic transport and thermal transport modeling, and beam shaping in QCLs. With a focus on recent developments, such as frequency noise and frequency stabilization of QCLs, grating-outcoupled surface-emitting mid-infrared QCLs, coherent-power scaling of mid-IR and THz QCLs, metasurface-based surface-emitting THz QCLs, self-mixing in QCLs, and THz QCL sources based on difference-frequency generation, it also features detailed theoretical explanations of means for efficiency maximization, design criteria for high-power continuous-wave operation of QCLs, and QCL thermal modeling, enabling you to improve performance of current and future devices. Paving the way for new applications and further advancements, this is an invaluable resource for academics, researchers, and practitioners in electrical, opto-electronic, and photonic engineering.

An invaluable text for the teaching, design, and development of gas sensor technology. This excellent resource synthesizes the fundamental principles of spectroscopy, laser physics, and photonics technology and engineering to enable the reader to fully understand the key issues and apply them in the design of optical gas absorption sensors. It provides a straightforward introduction to low-cost and highly versatile near-IR systems, as well as an extensive review of mid-IR systems. Fibre laser systems for spectroscopy are also examined in detail, especially the emerging technique of frequency comb spectroscopy. Featuring many examples of real-world application and performance, as well as MATLAB computer programs for modeling and simulation, this exceptional work is ideal for postgraduate students, researchers, and professional engineers seeking to gain an in-depth understanding of the principles and applications of fibre-optic and laser-based gas sensors.