Progress in high-power continuous-wave quantum cascade lasers [Invited].

Area of Science:

• Optics and Photonics
• Semiconductor Lasers
• Infrared Technology

Background:

• Quantum cascade lasers (QCLs) and interband cascade lasers are unique in directly converting electrical power to mid- and long-infrared optical power at room temperature.
• Recent advancements have enabled multi-watt continuous-wave operation with efficiencies exceeding 10% across broad infrared spectral regions.

Purpose of the Study:

• To review the significant progress in high-power quantum cascade lasers over the past decade.
• To provide an overview of key design techniques and future prospects for power scaling.

Main Methods:

• Review of active region, waveguide, and thermal design strategies for high-power QCLs.
• Discussion of die packaging techniques for demanding applications.
• Analysis of power scaling potential with increased lateral device dimensions.

Main Results:

• Demonstration of multi-watt continuous-wave room temperature operation with >10% efficiency in mid- and long-wave infrared.
• Identification of critical design elements for enhanced laser performance and thermal management.
• Analysis indicates potential for 10-20W optical power output through lateral scaling.

Conclusions:

• High-power QCLs represent a mature technology with substantial recent progress.
• Continued development in design and packaging techniques promises further power scaling for infrared laser platforms.
• Coherent and spectral beam-combining offer pathways to very high-power infrared systems.