Photonic jets for highly efficient mid-IR focal plane arrays with large angle-of-view

Area of Science:

• Optoelectronics
• Nanotechnology
• Infrared Imaging

Background:

• Pixel size reduction in mid-wave infrared (MWIR) focal plane arrays (FPAs) increases resolution but challenges light collection and angle-of-view (AOV).
• Existing methods struggle to maintain high light efficiency and wide AOV with smaller pixels.

Purpose of the Study:

• To propose and validate a novel approach using photonic jets from dielectric microspheres for efficient light coupling into MWIR FPAs.
• To develop scalable manufacturing techniques for integrating microspheres with FPAs.
• To optimize microsphere design for maximal AOV.

Main Methods:

• Utilized air suction through microhole arrays for large-scale, ordered assembly of dielectric microspheres.
• Employed simplified 2D Finite Difference Time Domain (FDTD) modeling to optimize microsphere integration (partial immersion, controlled melting).
• Investigated the impact of refractive index and diameter on AOV.

Main Results:

• Achieved scalable, ordered microsphere arrays with a low defect rate (~1%) via air suction assembly.
• Demonstrated significantly enhanced AOVs compared to standard microlens arrays, reaching ~8° (back-illuminated) and ~20° (front-illuminated).
• Optimized microsphere designs for maximum AOV based on optical properties and integration methods.

Conclusions:

• Photonic jets from dielectric microspheres offer a promising solution for high-efficiency light coupling and wide AOV in MWIR FPAs.
• The developed air suction assembly technique enables cost-effective, large-scale production of integrated microsphere arrays.
• This approach overcomes limitations of traditional microlens arrays, paving the way for next-generation infrared imaging systems.