Mid-infrared materials and devices on a Si platform for optical sensing

Area of Science:

• Photonics and optical sensing
• Materials science for integrated devices
• Mid-infrared (mid-IR) technology

Background:

• On-chip sensing requires advanced photonic materials and devices operating in the mid-infrared (mid-IR) spectrum.
• Silicon photonics offers a robust platform for developing integrated mid-IR sensors.
• Existing mid-IR sensors face challenges in sensitivity, selectivity, and integration.

Approach:

• Demonstration of silicon pedestal waveguides as broadband mid-IR sensors.
• Development of low-loss silicon nitride (SiN) waveguides for differential mid-IR sensing.
• Fabrication of chalcogenide glass photonic crystal cavities and microdisk resonators for high-sensitivity mid-IR sensing.
• Integration of polymer functionalization layers to enhance sensor performance.
• Design and fabrication of mid-IR chalcogenide waveguides integrated with polycrystalline PbTe detectors on a monolithic silicon platform.
• Utilizing a low-index spacer layer for efficient evanescent coupling in waveguide-detector systems.

Key Points:

• Silicon pedestal waveguides exhibit broadband mid-IR sensing capabilities.
• Low-loss SiN directional couplers are suitable for differential sensing.
• Chalcogenide-based photonic crystal cavities and microdisk resonators offer high sensitivity for mid-IR detection.
• Polymer layers improve sensor sensitivity and selectivity.
• Monolithic integration of mid-IR waveguides and PbTe detectors on silicon is achieved.
• Successful fabrication of prototype waveguide-integrated mid-IR detectors.

Conclusions:

• The reviewed work demonstrates a versatile platform for mid-IR on-chip sensing using silicon photonics.
• Integrated photonic devices, including waveguides, resonators, and detectors, show significant promise for advanced optical sensing.
• The developed technologies pave the way for novel mid-IR sensing applications in various fields.