InAsSb/InAsPSb multiple quantum well disk cavities with pedestal structures on a GaSb substrate for mid-infrared...

Area of Science:

• Optics and Photonics
• Materials Science
• Semiconductor Physics

Background:

• Whispering-gallery-mode (WGM) resonators are crucial for low-threshold lasers and sensitive detectors.
• Mid-infrared (MIR) applications require specialized materials and fabrication techniques for efficient light confinement.

Purpose of the Study:

• To develop fabrication techniques for mid-infrared InAsSb/InAsPSb multiple quantum well (MQW) disk cavities.
• To demonstrate the optical performance of these MIR disk cavities.

Main Methods:

• Inductively coupled plasma-reactive ion etching (ICP-RIE) with a BCl3/Ar gas mixture for smooth sidewalls.
• Selective wet etching using dilute hydrofluoric acid to form the pedestal.
• Careful control of lateral etching extent for radial mode confinement.
• Optical pumping of fabricated 30-μm-diameter disk cavities.

Main Results:

• Successfully fabricated MIR disk cavities with InAsSb/InAsPSb MQWs on a GaSb substrate.
• Achieved smooth sidewalls and selective pedestal formation using optimized etching processes.
• Observed whispering gallery modes around 4.1 μm.
• Demonstrated WGM operation up to 90 K.

Conclusions:

• The developed fabrication process enables the creation of high-quality MIR disk cavities.
• The InAsSb/InAsPSb MQW material system is suitable for MIR WGM resonator applications.
• The demonstrated performance up to 90 K highlights the potential for practical MIR photonic devices.