▎ 摘　　要

A directional energy focusing system based on parallel-monolayer graphene sheets is proposed and is analytically and numerically investigated in this paper. By properly designing the chemical potential distributions, we obtain a similar to 0.8-nm-size focusing point at desired positions with energy enhancement factor of over 2410. The flexible tunability of the transmission properties enables us to shut one parallel pair propagation down and guide the waves to the other branch. The light signal at the focal point is efficiently slowed down to over 10,000 times the speed in vacuum as well. The proposed structure may find potential applications in integrated circuits, on-chip systems or energy storage.