Metasurface fan-out diffractive optical elements

Here we report the design and realization of dielectric fan-out diffractive optical elements (DOEs) operating in visible range and with nanobrick depth-width-ratio as low as 1.5. The metasurface-based fan-out DOEs realized here, when illuminated by an incident beam with 633 nm wavelength, the uniform 4×4 spot arrays with an extending angle of 32°×32° can be obtained in the far field. Experimental results agree well with the theoretical analysis and numerical simulation conclusions. Because of these advantages of the single-step nonstructural fabrication procedures, continuous and accurate phase manipulation, and strong polarization conversion, the metasurface-based fan-out DOEs could be utilized for various applications such as optical sensing, lidar, laser machining and so on.