Research On Terahertz Encoders And Relevant Devices Based On Metamaterials

In the past decades,the research on metamaterials has more progress.The development of devices working in microwave and terahertz bands has got great achievement.With the development of micro-nano fabrication,the manufacture and design of terahertzmetamaterials are not difficult,and the application of terahertz devices will be mature.Nowadays,the terahertz is not a "terahertz gap" in the electromagnetic wave spectrum,which has much progress in the past decade.Terahertz is an attractive research field,with applications for physics,medicine,biochemistry industries.Terahertz photon energy is lower than that of visible light and X-ray,and terahertz radiation has unique fingerprint characteristics of biomacromolecules.Since the band is much wider than the microwave bands,and the directionality is better,terahertz modulation technology becomes a focus of research in the communications field.The device based on metamaterial is a novel and powerful method to control electromagnetic waves.In this paper,we research on the metamaterial-based terahertz active devices.Especially,the multi-bit encoder.The details are as follows:We propose a multi-bit encoder realized with graphene-based metamaterials,which can switch the transmission amplitude with high or low statues at 0.20 THz and 0.33 THz,and the modulation depth can reach than 79.6%.And we propose a dual-band amplitude shiftkeying terahertz encoder based on 2 dimensions electron gas metamaterial,which can control the transmission amplitude of the terahertz waves on high or low at 0.43 THz and 0.81 THz,independently,and the modulation depth is 96% and 86%.We study the theory and the resonance mode of the encoders.The codes are defined with the different statues of encoders while the different bias applies.We simulate and analyze each surface current densities of the encoder in different statues.We propose an active multi-band filter based on semiconductor-metallic hybrid metamaterial control with laser-pump(lambada shorter than 800 nanometers),which has 3 switchable passbands in the terahertz regime.The central frequency of the filter is 0.22 THz,0.59 THz,and 0.89 THz,the maximum transmission amplitude is 76%,75.4%,and 66.3%,respectively.We study the theory and resonance mode of the filter and design the encoder based on it preliminary.This work will promote the development of integrated terahertz devices and terahertz communication.It is a foundation that some researches of the multibit encoderWe propose a terahertz active device based on the control of lattice modes.We study the transmission spectrum of the U-shape metamaterials with different periodic in 125,145,165,185,2058)using simulation and experiment.We print a holder with the 3D printer to measure the sample with different theta in 0°,30°,60° with the periodic is 1458).This work will promote the development of integrated terahertz devices and terahertz communications.It is a foundation of that some researches of the multi-bit encoder.