Book contents
- Frontmatter
- Dedication
- Contents
- Preface
- Part I Bandstructure Engineering, Modeling and State-of-the-Art QCLs
- 1 Basic Physics of Intersubband Radiative and Nonradiative Processes
- 2 State-of-the-Art Mid-Infrared QCLs: Elastic Scattering, High CW Power, and Coherent-Power Scaling
- 3 Long-Wavelength Mid-Infrared Quantum Cascade Lasers
- 4 Overview of the State-of-the-Art Terahertz QCL Designs
- 5 Simulating Quantum Cascade Lasers: The Challenge to Quantum Theory
- 6 Coupled Simulation of Quantum Electronic Transport and Thermal Transport in Mid-Infrared Quantum Cascade Lasers
- Part II Active Research Topics
- Part III Applications
- Index
4 - Overview of the State-of-the-Art Terahertz QCL Designs
from Part I - Bandstructure Engineering, Modeling and State-of-the-Art QCLs
Published online by Cambridge University Press: 25 August 2023
- Frontmatter
- Dedication
- Contents
- Preface
- Part I Bandstructure Engineering, Modeling and State-of-the-Art QCLs
- 1 Basic Physics of Intersubband Radiative and Nonradiative Processes
- 2 State-of-the-Art Mid-Infrared QCLs: Elastic Scattering, High CW Power, and Coherent-Power Scaling
- 3 Long-Wavelength Mid-Infrared Quantum Cascade Lasers
- 4 Overview of the State-of-the-Art Terahertz QCL Designs
- 5 Simulating Quantum Cascade Lasers: The Challenge to Quantum Theory
- 6 Coupled Simulation of Quantum Electronic Transport and Thermal Transport in Mid-Infrared Quantum Cascade Lasers
- Part II Active Research Topics
- Part III Applications
- Index
Summary
This chapter reviews typical waveguide and active region designs for quantum cascade lasing in the terahertz (THz) frequency range. Operating principles are analyzed in details with special attention paid to the most recent developments with the state-of-the-art device performance. The maximum operation temperature of THz QCL is still the main obstacle for its wide employment in applications, although it has been lifted to 250 K, allowing cryogenic-free THz coherent radiation for potentially portable applications. Optimization of various limiting factors in the most advanced resonant-phonon designs or the combined designs with scattering-assisted injection scheme could be promising for further breakthroughs in achieving higher temperature operations. The discussions in this chapter mainly focus on the matured GaAs/AlGaAs material system, but the design strategies can be applied to THz QCLs utilizing other material systems, which may overcome the main challenges of the GaAs/AlGaAs material system and achieve better performance in the future.
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- Mid-Infrared and Terahertz Quantum Cascade Lasers , pp. 138 - 152Publisher: Cambridge University PressPrint publication year: 2023