III-V on CaF₂: a possible waveguiding platform for mid-IR photonic devices

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Condensed Matter Physics

Background:

• Metallic claddings in waveguides limit optical functionality and mid-infrared (mid-IR) applications.
• Existing waveguide designs often lack flexibility for advanced device integration.

Purpose of the Study:

• To develop a novel waveguide fabrication technique using low-index dielectric claddings.
• To demonstrate enhanced light-matter interactions and explore mid-IR waveguiding potential.

Main Methods:

• Replacement of metallic waveguide cladding with transparent low-index materials (CaF2, BaF2).
• Demonstration of strong light-matter coupling using intersubband transitions and dispersive resonators.
• Numerical simulations to evaluate mid-IR waveguiding performance and losses.

Main Results:

• Achieved strong light-matter coupling at 300 K and 78 K with intersubband transitions (λ∼10 μm).
• Preserved elevated optical confinement with a low-index cladding (n≈1.4).
• Simulated mid-IR waveguiding losses in the range of 1-10 cm⁻¹.

Conclusions:

• The developed technique offers a viable platform for mid-IR waveguiding.
• Replacing metallic claddings enables new functionalities like substrate-based optical entryways and double-side patterning.
• This approach paves the way for advanced integrated photonic devices in the mid-IR spectrum.