Resonant Meta-Lens in the Visible

Abstract

Meta-lenses can offer potential improvements over traditional optical components in imaging, display, and detection. Initial meta-lenses strive for uniform spectral responses over broadband for full-color imaging. Nevertheless, enhancing wavelength selectivity remains crucial for specific applications, such as fluorescence imaging and augmented reality, requiring specific wavelengths. Current methods struggle to balance nonlocal resonance with local phase control or introduce an additional filter layer. Here, an all-dielectric resonant meta-lens for wavelength-selective focusing based on the Fresnel zone plate design is experimentally demonstrated. The coupling between nonlocal lattice resonance and local Mie-type resonance is effectively manipulated to control the reflection and bandwidth. Without considering the balance between nonlocal resonance excitation and local phase control, the resonant meta-lens can reflectively focus at a resonant wavelength of 460 nm while allowing normal transmission at non-resonant wavelengths, which is generally restricted in conventional metallic counterparts. Simulation (experimental) results indicate a high color purity of 90% (66%), surpassing those of meta-lenses with filtering functions. A multi-resonant meta-lens is further designed for red, green, and blue colors. This work offers enhanced options for wavelength-selective meta-lenses, expanding their potential in optical imaging and display applications.