Researchers are tackling a fundamental challenge in augmented reality (AR) and virtual reality (VR) technology: creating comfortable, high-quality near-eye displays. Traditional near-eye displays face a significant limitation – they must be positioned very close to the eye, which causes user discomfort during extended use. While conventional optical components can help adjust the light path and reduce eye strain, they tend to be bulky and heavy, making them impractical for head-mounted devices.
A research team, led by Prof. Arka Majumdar from the University of Washington, along with collaborators from MIT, has developed an interesting solution using metalenses. These are ultra-thin optical components made of nano-structures arranged in two dimensions. The researchers created a metalens doublet system – essentially two metalenses working together – specifically designed for near-eye displays.
What makes their approach particularly clever is how they integrated the human pupil into their design. Rather than trying to create a complete optical system, they used the human pupil as a natural aperture, making it an integral part of the optical path. This allowed them to achieve a remarkably wide field of view (FOV) of up to 60-80 degrees, while maintaining image quality that rivals traditional eyepiece systems.
The system works by projecting images that appear to be at infinity, despite the display being physically close to the eye. This is achieved through careful optimization of the two-layer metalens design and the strategic use of the pupil as an aperture. The researchers demonstrated this concept by constructing an eye model that included an iris (acting as the pupil), a refractive lens (representing the eye’s natural lens), and a camera sensor. They were able to achieve high-quality imaging at angles of incidence up to 30 degrees, effectively creating a 60-degree full field of view.
The metalens doublets were designed with diameters in the centimeter range, paired with apertures measuring several millimeters – dimensions that match the actual size of human eyes and pupils. This practical approach to scaling sets this work apart from previous metalens developments, which typically featured much smaller apertures that weren’t suitable for real-world applications.
The researchers acknowledge that while their system doesn’t maintain diffraction-limited performance across the entire field of view, this limitation aligns well with how human vision actually works. Our eyes naturally have relaxed requirements for ultra-wide FOV in applications like AR/VR, as we tend to focus on specific points rather than maintaining perfect clarity across our entire field of vision.
Reference
Sun, J., Li, T. Cascaded metalenses boost applications in near-eye display. Light Sci Appl 14, 58 (2025). https://doi.org/10.1038/s41377-024-01699-5
