▎ 摘　　要

We propose a graphene ribbon based metalens that can achieve the function of tunable metalens in THz region. Different from these graphene ribbon based metalens that have been reported before, the proposed metalens can focus the x- and y-polarized incident THz wave separately by reconfiguring the Fermi energy distribution of the graphene ribbons. The proposed metalens can also focus the incident wave at different spatial positions and different working frequencies. The simulated results are in good agreement with the designed values. Our findings are beneficial in designing new active terahertz devices.