Inverse Design of Thermal Imaging Metalens Achieving 100° Field of View on a 4 × 4 Microbolometer Array

Area of Science:

• Optics and Photonics
• Metamaterials
• Infrared Imaging

Background:

• Conventional long-wave infrared (LWIR) optics are often expensive, inefficient, or have limited fields of view (FoV), hindering their adoption in consumer and Internet of Things (IoT) platforms.
• Scalability of LWIR imaging is restricted by the bulk and cost of traditional multi-element lens systems.

Purpose of the Study:

• To design and demonstrate an inverse-designed metalens for LWIR imaging optimized for low-cost, low-power consumer and IoT edge devices.
• To achieve a wide field of view (FoV) and robust performance suitable for microbolometer arrays.

Main Methods:

• Utilized adjoint-based inverse design integrated with fabrication-aware constraints.
• Incorporated a cone-shaped source model to accurately account for oblique incidence during optimization.
• Developed a multi-level metalens structure.

Main Results:

• The inverse-designed metalens achieved a wide FoV up to 100°.
• Demonstrated robust focusing efficiency and stable angle-to-position mapping on 4x4 microbolometer arrays.
• Achieved superior imaging performance compared to a commercial narrow FoV lens in low-resolution, low-cost edge LWIR modules.

Conclusions:

• The proposed metalens offers a practical, compact, and energy-efficient solution for LWIR imaging in consumer applications.
• This design eliminates the need for bulky optical stacks, reducing cost and form factor.
• Enables new applications in smart buildings, mobile sensing, and surveillance.