Metalens is a device based on metasurfaces and metagrating,which can flexibly regulate the phase,polarization,and amplitude of light.It has the advantages of lightweight and easy-integration.However,the fabrication cycle time of metalens is long and the cost is great,and it is extremely necessa-ry to find an easy-to-process,low-cost and high-efficient method.In this work,an all-dielectricterahertz(THz)metagrating with highly efficiency wavefront control in THz range is proposed.The all-dielectric metagrating bends the electromagnetic waves beam into the T-1 diffraction order when the electromag-netic wave is incident normally.In the simulation,more than 83.44％of the transmitted energy is con-centrated in the T-1 diffraction order for P-polarized light and more than 82.73％for S-polarized light.Then,based on the all-dielectric metagrating,a metalens with numerical aperture of NA=0.39 at 0.14 THz is proposed,the metalens has been fabricated by 3D printing.The focusing capability of the met-alens is characterized by utilizing the scanning measurement system.The focal spot with the focusing dis-tance of 114.5 mm is achieved,the measured and anticipated results are satisfactorily congruous with one another,which could validate our design.Meanwhile,the size of the focal spot is obtained.The transmis-sion THz imaging system is performed to characterize the imaging capability of the metalens.This work holds great promise for extensive applications in light sensing,communication,and super-resolution ima-ging.
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