▎ 摘　　要

A parallel graphene pair with two cavities is proposed. Owing to the introduced cavities, the symmetric coupling resonator is realized, and the propagating surface plasmon mode is modulated. This structure exhibits a novel band-pass filtering effect in the mid-infrared region. The resonance wavelength is tuned regularly by varying the length of the resonator and the space between the graphene sheets. Without re-fabricating a new structure, a small change in the chemical potential of the graphene can also tune the transmission spectrum, which is optimized by varying the widths of cavities. Our results support the fabrication of ultra-compact mid-infrared nano-integrated circuits. (C) 2014 The Japan Society of Applied Physics