Graphene based Organic Optical Terahertz Modulator

Abstract

We investigate a high-efficiency broadband terahertz wave modulator with structures made from the conjugated polymer MEH - PPV, graphene, and Si, irradiated with an external excitation laser. We demonstrate a strategy that can alleviate the tradeoffbetween the requirements of modulation depth and modulation speed in polymer/silicon terahertz wave modulators. Using terahertz time-domain and continuous-wave systems, we measured both the terahertz transmission modulation properties and the time responses of the modulator structures. The conjugated polymer/graphene/silicon structure achieved a high modulation factor of93% for transmission as well as improved the modulation speed of the devices based on polymer/silicon. The high modulation efficiency of the polymer/graphene/silicon structure was induced by the enhancement in carrier density and the extremely high carrier mobility of graphene, respectively.