Recently, Professor Xiaowei Sun's team, Chairman of the Alliance and Executive Dean of the Institute of Nanoscience and Applications at Southern University of Science and Technology, published a research paper entitled "An achromatic metasurface waveguide for augmented reality displays" in the top international academic journal *Light: Science & Applications*. This research proposes an innovative metasurface waveguide technology that fundamentally solves the color difference problem in augmented reality (AR) displays for the first time, opening up new directions for the development of AR display technology.
Throughout the evolution of AR technology, display systems have consistently faced the dual challenges of achieving greater clarity and thinner profiles. From early reflective displays to today's waveguide displays, each iteration of the technology has moved towards this goal. Diffractive waveguides, due to their ultra-thin characteristics, have become a core technology in mainstream AR devices such as HoloLens and Meta Orion. However, image distortion caused by dispersion effects remains a technological bottleneck in this field.
Schematic diagram of metasurface waveguide AR display system
Sun Xiaowei's team has proposed a novel solution using an innovative reverse engineering method: successfully overcoming the chromatic aberration problem by utilizing metasurface couplers and a single-layer high-refractive-index optical waveguide. Metasurfaces are optical components composed of artificial nanostructures that can precisely control the phase, amplitude, and polarization characteristics of light. By optimizing the geometry of the metasurface coupler, the research team ensured that the RGB three-color light had a consistent deflection angle and coupling efficiency upon emission, effectively eliminating the chromatic aberration problem.
Comparison of conventional optical waveguides and metasurface optical waveguides. (a) Conventional optical waveguides couple light into the waveguide through first-order diffraction, resulting in wavelength-dependent deflection angles; (b) The K-vector diagram of conventional optical waveguides shows a smaller overlapping full-color field of view; (c) Metasurface optical waveguides achieve aberration-free optical coupling through higher-order diffraction; (d) The KK diagram of metasurface optical waveguides shows a larger light vector.
This technological breakthrough not only solves the color difference bottleneck of traditional coupling elements but also provides a completely new technological path for full-color optical waveguide displays. Metasurface waveguide technology possesses several significant advantages: its single-layer structure simplifies manufacturing processes, its high refractive index design expands the field of view, and its optimized coupling efficiency ensures full-color display performance. These characteristics give it enormous application potential in next-generation AR devices, marking a new stage in the development of AR display technology.
AR full-color display effect
The first author of this research is Tian Zhongtao, a joint doctoral student trained by Southern University of Science and Technology (SUSTech) and Pengcheng Laboratory, with Professor Sun Xiaowei as the sole corresponding author. SUSTech is the first corresponding institution, and Pengcheng Laboratory is the second corresponding institution. This research was supported by the National Key Research and Development Program of China, Guangdong Province, Shenzhen Municipality, and other institutions. (Image source: Southern University of Science and Technology)
