▎ 摘　　要

A hybrid graphene-metal grating is simulated and analyzed at terahertz frequency band by using the hybrid implicit-explicit finite-difference time domain (HIE-FDTD) method. To simulate the graphene layer accurately, both the interband and intraband conductivity of the graphene are incorporated into the HIE-FDTD method by using the auxiliary differential equations and Pade fitting technique. Numerical results show that the HIE-FDTD method has excellent computational accuracy and its computational efficiency is considerably improved from that of the conventional FDTD method. Besides, numerical results validate that the graphene can achieve tunable terahertz grating through controlling its chemical potential, and the interband conductivity of the graphene has important effects on the performance of the grating.