Phys.org September 28, 2022
Augmented reality (AR) glass needs to be highly transparent over almost the entire visible spectrum. In traditional AR there is a tradeoff in terms of quality and brightness between the external scene and the contextual information you want to visualize. A team of researchers in the US (Columbia University, City University of New York) has demonstrated nonlocal dielectric metasurfaces in the near-infrared that offer both spatial and spectral control of light, realizing metalenses focusing light exclusively over a narrowband resonance while leaving off-resonant frequencies unaffected. This is made possible by quasi-bound state in the continuum encoded with a spatially varying geometric phase. They leveraged this capability to design a versatile platform for multispectral wavefront shaping where a stack of metasurfaces, each supporting multiple independently controlled quasi-bound states in the continuum, molds the optical wavefront distinctively at multiple wavelengths and yet stay transparent over the rest of the spectrum. The platform is scalable to the visible for applications in augmented reality and transparent displays…read more. Open Access TECHNICAL ARTICLEÂ
Experimental results of a resonant radial metalens with NA = 0.2. Credit: Light: Science & Applications volume 11, Article number: 246 (2022)Â