Broadband absorption enhancement of graphene in the ultraviolet range based on metal-dielectric-metal configuration.

Light absorption of suspended monolayer graphene in the ultraviolet range is relatively low, which impedes the potential applications for graphene-based optoelectronic devices. To enhance the light-matter interaction in a wide spectral range, we propose two plasmonic structures based on a metal-dielectric-metal configuration. After rigorous optimization of geometric parameters, broadband and enhanced ultraviolet light absorption of graphene can be achieved. The bandwidth above 30% absorption rate can reach up to 245 nm (from 240 nm to 485 nm), while the relative bandwidth can reach up to 68%. The optimal absorption peak is as high as 54%. Besides, the absorption spectrum can be tuned by adjusting the geometric parameters. Physical insight is revealed with electric and magnetic field distributions. Furthermore, the tolerance for the incident angle is demonstrated, and the dependence of the polarization angle is discussed. Our approach shows promising potential for novel graphene-based applications in the ultraviolet range. [ABSTRACT FROM AUTHOR]