▎ 摘　　要

Narrowband perfect absorbers based on surface plasmon polariton resonance have been mainly used in label free sensing due to large quality factors and high surface sensitivities. In this work, it is proposed and theoretically demonstrated that narrowband perfect absorbers combined with graphene are capable of broadband mid-IR light modulation. A large intensity modulation depth over 90% can be obtained in the wavelength range from 5 mu m to 6 mu m, which is 2.5-fold enhanced compared with that of a broadband perfect absorber. Phase modulation application has also been demonstrated, and a tuning range of 180 degrees is achievable. The influences of structure parameters on modulation performance are discussed at last using coupled mode theory. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement