Optical modulation characteristics of graphene supercapacitors at oblique incidence in visible-infrared region

摘要

Multi-angle modulation properties of electrolyte gated graphene visible-infrared modulators with super capacitor structures have been examined in both experiment and theory. Both transmission and reflection geometries have been studied, and the results show that all the modulations of these devices are gate voltage and wavelength dependent. Maximum modulation depths for transmission device similar to 3% and reflection modulator similar to 5% are obtained, which can be attributed to the electrolyte assistant considerable change of the Fermi energy with tunable gate voltage. Moreover, little incident angle dependency can be observed with a certain gate voltage. Theoretical analysis based on the different tangential and normal optical responses of the quartz/graphene/eletrolyte interface has been used to explain the phenomena, which indicated a common effect of p-polarized and s-polarized light. This work offers useful insight into a multi-angle application of the graphene-based optical modulator in visible-infrared region. (C) 2017 Elsevier Ltd. All rights reserved.