Controllable Large-Area Fabrication of Illumination Angle-Sensitive Metasurfaces Using Femtosecond Laser

Plasmonic nanostructures have shown significant potential for manipulating electromagnetic waves at the subwavelength scale. Plasmonic nanostructures exhibit optical bending, absorption, and scattering properties, as well as strong plasmonic resonance. However, the current fabrication methods heavily rely on photolithography or templates, which pose limitations in terms of cost, efficiency, complexity, and scalability. In this study, a novel method is proposed for the controllable fabrication of ordered metal–insulator-metal (MIM) gold nanobump arrays by femtosecond laser direct writing. The fine regulation and control of the shape and size of the gold nanostructure can be realized by changing laser pulse energy, which leads to the change of the resonance light scattering and the plasmon structure color of individual structure. Large-scale periodic gold nanostructure with illumination angle sensitive characteristic can be achieved by adopting the combination mode of high-power, high-attenuation, frequency-doubled laser, and a telephoto objective lens. This may have great application potential in the aspects of high-resolution imaging, information storage, nanodevices, optical metasurfaces, and biosensors.