Dually guided-mode-resonant graphene perfect absorbers with narrow bandwidth for sensors. (19th July 2016)

• Record Type: Journal Article
• Authors: Long, Yongbing; Li, Yuanxing; Shen, Liang; Liang, Wenyue; Deng, Haidong; Xu, Haitao
• Is Part Of: Journal of physics. Volume 49:Number 32(2016)
• Publication Date: 2016-07-19
• Subjects: perfect absorption -- dually guided-mode resonance -- graphene -- sensors; Physics -- Periodicals; 530
• DOI: 10.1088/0022-3727/49/32/32LT01
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: Dually guided-mode-resonant graphene perfect absorbers are numerically proposed by placing graphene grips on dielectric subwavelength grating that is backed by one-dimensional photonic crystals (1DPCs). By optimizing parameters of the grating, perfect absorption with a narrow bandwith of 1.1 nm is achieved at a wavelength of 632.8 nm. The perfect absorption is attributed to the dual excitation of the guided-mode resonance of both the grating and the 1DPCs. When this type of absorber is used in refractive index sensors, the figure of merit reaches as high as 124, a value much higher than that of the sensors based on metal perfect absorbers. In addition, it is observed that a slight change of the refractive index in the surrounding environment causes large intensity variation of reflection at a fixed wavelength; accordingly, high index sensitivity is achieved for the sensors.