All-dielectric terahertz wave metagrating lens based on 3D printing low refractive index material

A metagrating lens with a high numerical aperture (NA = 0.9) is designed based on the grating diffraction principle and the unit structure of the asymmetric scattering mode. The metagrating lens is composed of all -dielectric material with low refractive index and achieves good focusing at an operating frequency of 0.1 THz. In our experiments, we used 3D printing technology to fabricate the metagrating lens to further reduce the fabrication cost of the metalens and avoid the disadvantages of conventional optical devices that are large and costly.