From far-infrared detectors to THz QCLs

Area of Science:

• Quantum Electronics
• Solid-State Physics
• Optoelectronics

Background:

• The author's research transitioned from far-infrared superconducting devices.
• The development of terahertz quantum cascade lasers (THz QCLs) is a significant milestone.
• This work spans over 12 years (1990-2002).

Purpose of the Study:

• To reflect on the author's personal journey in developing THz QCLs.
• To share unpublished episodes and insights from the development process.
• To commemorate the 30th anniversary of quantum cascade lasers.

Main Methods:

• Personal memoir and reflection on research experiences.
• Focus on the author's group's development of THz QCLs.
• Not a comprehensive review of the field.

Main Results:

• Achieved lasing threshold for the first THz QCL developed by the author's group.
• Successfully transitioned from research on superconducting devices to THz QCLs.
• Documented a 12-year research effort involving multiple graduate students.

Conclusions:

• The development of THz QCLs was a challenging yet rewarding process.
• Personal experiences and learning were central to the research journey.
• The successful operation of THz QCLs marks a significant scientific achievement.