Low-dissipation 7.4-µm single-mode quantum cascade lasers without epitaxial regrowth

Area of Science:

• Optoelectronics
• Quantum Cascade Lasers
• Infrared Spectroscopy

Background:

• Quantum cascade (QC) lasers are crucial for mid-infrared applications.
• Existing designs often have high power consumption, limiting their use in portable devices.
• Conventional buried-heterostructure (BH) QC lasers require complex epitaxial regrowth.

Purpose of the Study:

• To report continuous-wave operation of single-mode QC lasers with low power consumption.
• To demonstrate a fabrication process that avoids epitaxial regrowth.
• To enable QC laser use in compact infrared spectroscopy instruments with strict power budgets.

Main Methods:

• Fabrication of QC lasers using narrow, plasma-etched waveguides.
• Integration of distributed-feedback sidewall gratings.
• Cladding with sputtered aluminum nitride.
• Testing continuous-wave operation up to 40 °C.

Main Results:

• Achieved single-mode operation near 7.4 µm.
• Threshold power consumption below 1 W.
• Operation demonstrated at temperatures up to 40 °C.
• Fabrication without epitaxial regrowth.
• Power consumption comparable to lowest-dissipation BH QC lasers.

Conclusions:

• The developed QC lasers offer low power consumption and high performance without epitaxial regrowth.
• These devices are suitable for compact, power-limited infrared spectroscopy applications.
• The fabrication method presents a viable alternative for producing efficient QC lasers.