Design of dual-wavelength polarization control metasurface lens

Abstract

With the rapid development of modern optics, optical elements have become an indispensable part of an optical system. A metasurface is a nanostructure composed of arrays of sub-wavelength scatterers and is widely used due to its simple structure, thin thickness, easy integration, and high utilization rate. This paper designs a polarization-multiplexed transmissive metasurface lens in the visible light band 690 nm and near-infrared light band 880 nm. The metasurface lens combines the x-polarized lens design with the y-polarized lens design to realize three metasurface lenses with dual wavelength and different polarization states under the same metasurface. The metasurface lenses are: a coaxial confocal metasurface lens with the focus length of f1=f2=7 215 nm, an off-axis metasurface lens with the focus length of f1=f2=7 221 nm and with a displacement of xd=±4 000 nm, and a coaxial metasurface lens with the focus length of f1=7 000 nm and f2=10 000 nm, respectively. They have not only a high numerical aperture of 0.8 but also a good focusing capability with a full width at half maximum close to diffraction limit, and their space utilization is also improved. This compact and highly numerical aperture and high spatial utilization of dual-wavelength polarization multiplexing metasurface design provides an effective solution for the development of focusing lens and has unique potentials and advantages in fluorescent microlens, optical imaging, etc.