Graphene's ultrafast optical response and broad spectral coverage make it attractive for all-optical modulation. However, existing graphene modulators require high pump fluence due to short photo-carrier lifetime and limited absorption. This paper presents modulator designs using graphene-metal hybrid plasmonic metasurfaces to enhance light-graphene interaction. Near and mid-infrared (1.56 µm and >6 µm) high-speed modulators with significantly reduced pump fluence (1-2 orders of magnitude) and enhanced modulation are demonstrated. Ultrafast measurements show response times determined by graphene's picosecond photocarrier relaxation times. The designs are promising for ultrafast all-optical modulators at mid-and far-infrared wavelengths.

Ali Basiri, Md Zubair Ebne Rafique, Jing Bai, Shinhyuk Choi, Yu Yao