Compact eye camera with two-third wavelength phase-delay metalens.

Area of Science:

• Optics and Photonics
• Nanotechnology
• Biomedical Imaging

Background:

• Mobile devices require compact, high-performance imaging systems.
• Metalenses offer an alternative to traditional lenses but face manufacturing challenges.
• High-aspect-ratio nanostructures increase cost and reduce yield in metalens fabrication.

Purpose of the Study:

• To propose an infrared metalens design that reduces nanostructure aspect ratio.
• To demonstrate that reduced nanostructure height does not compromise metalens performance.
• To develop a compact eye imaging system for gaze tracking and iris authentication.

Main Methods:

• Designed an infrared metalens with a wide field of view and reduced nanostructure aspect ratio.
• Utilized a phase modulation depth of 4π/3, two-thirds of conventional designs.
• Integrated the metalens into a prototype compact eye imaging system.

Main Results:

• Achieved a 120-degree field of view with the metalens system.
• Demonstrated reduced nanostructure height without performance degradation.
• Developed an ultracompact eye camera module with a total track length of 1.758 mm.

Conclusions:

• The proposed metalens design overcomes manufacturing limitations for commercial adoption.
• The compact eye imaging system is suitable for gaze tracking and iris authentication.
• This technology has significant potential for commercialization in extended reality devices.