Dual-band narrow-band absorber with perfect absorption peaks in mid-infrared and near-infrared based on surface plasmon resonance

The use of infrared light and the development of related technologies have covered all aspects of people's lives. In many aspects, researchers are more concerned about the perfect absorption of infrared waves. With the continuous development of surface plasmon photonics in recent years, new ideas are provided for related infrared optoelectronic devices. To this end, we designed a perfect narrow-band dual-band absorber based on the surface plasmon resonance (SPR) theory by combining graphene with nano-metal arrays. The two absorption modes are located in the near-infrared and mid-infrared bands (i.e. 2176.47 nm and 3538.37 nm), and the absorption rates are 97.89 % and 99.80 %, respectively. At the same time, the absorber has high refractive index sensitivity (1051.10 nm/RIU) and strong environmental adaptability. The absorber provides a new possibility for the development of infrared technology, which can play a significant role in the fields of detection, sensing and medical treatment.