Gradient-metasurface directional photodetectors

Area of Science:

• Optics and Photonics
• Materials Science
• Device Engineering

Background:

• Angle-sensitive photodetectors are crucial for advanced imaging applications like lightfield sensing and phase imaging.
• Existing technologies often face limitations in footprint, resolution, and sensitivity.

Purpose of the Study:

• To demonstrate the use of plasmonic gradient metasurfaces for tailoring photodetector angular response.
• To enable novel imaging functionalities with enhanced miniaturization and design flexibility.

Main Methods:

• Fabrication of plasmonic gradient metasurfaces.
• Integration of metasurfaces with generic planar photodetectors.
• Characterization of the angular response of the fabricated devices.

Main Results:

• Successfully tailored the angular response of photodetectors using plasmonic gradient metasurfaces.
• Achieved sharp peaks in angular response via phase-matched coupling to guided plasmonic modes.
• Demonstrated reduced footprint and improved spatial resolution and sensitivity compared to diffractive approaches.

Conclusions:

• Plasmonic gradient metasurfaces offer a promising route for developing highly capable angle-sensitive photodetectors.
• This flat optics approach integrates seamlessly with image sensors, enabling miniaturization and new imaging capabilities.
• The demonstrated technique opens new avenues for advanced optical sensing and imaging systems.