Study On Modulating Terahertz Transmission By Granphene And Micro-nano Structure

Terahertz technology has a wide range of applications in communication,radar,imaging,detection,and biomedical.The terahertz modulator is one of the key devices.The performance of the terahertz modulator has great influence on the development of the terahertz technology.The modulation depth is one of the important indicators of the performance of the terahertz modulator.In this paper,starting with the electrically regulated single-layer grapheme terahertz modulators,and add subwavelength metal micro-nano structure to the modulator to study the modulation capability of terahertz modulator.There will be an extraordinary transmission phenomen when electromagnetic waves transmit through the metal micro-nano structure,and a local enhanced electric field will enhance the interaction effect in the vicinity of the structure.Based on the single layer micro-nano structure graphene terahertz modulator model a double micro-nano structure layer graphene terahertz modulator model was optimized.Using metal micro-nano structures of different shapes and sizes can provide different resonant frequency bands,a double micro-nano structure layer graphene terahertz modulator model is established.Based on the processing technology of semiconductor integrated circuits,a double micro-nano structure layer graphene terahertz modulator was experimentally fabricated and measured by a terahertz time-domain spectroscopy system.The modulation depth obtained at 0.54 THz is 33.7%,and obtained at 1.1 THz is 37.4%.The double micro-nano structure layer graphene terahertz modulator has one modulation band more than the single layer micro-nano structure graphene terahertz modulator,and the modulation depth is improved by about 10%.The modulation effect of modulator is affected by the thickness of the substrate layer,the quality of graphene and the alignment accuracy between the two layers of micro-nano structures.