Design And Research Of Modulator Based On Terahertz Band

With the research and exploration of the terahertz wave,the voices of various functional devices extending from the millimeter wave band to the terahertz wave band are becoming more and more popular.Because of the special properties of terahertz,there is still a lot of space for the development of the functional devices in the terahertz band.In this paper,based on the characteristics of electromagnetic metamaterials,we have designed and researched three devices of the multi-band terahertz resonator ultrawideband terahertz absorber and terahertz modulator.First of all,we use the I-shaped basic structure to design a single-band,dual-band and five-band terahertz resonator by adding different shapes of metal sheets and metal strips at different positions on the surface of the structure in this paper.The resonant frequencies of the three resonators are all concentrated in the range of 0.5 THz to 1.5 THz,and the transmission coefficients are all less than 7%.Secondly,on the basis of terahertz resonators,by adding a layer of metal with a thickness greater than the skin depth at the bottom,using the characteristics of the metal resonant split ring,combined with the good structure of the square,we design terahertz absorbers with the single split ring and the double split ring on square.Its absorption coefficient greater than 70% band up to 3.8THz,the maximum absorption coefficient can reach 99.97%,the absorption coefficient is perfect and the frequency band is ultra wide.Then,on the basis of terahertz absorbers,by adding a layer of semiconductor silicon which can change the conductivity to the upper part of the metal layer,using light to change the carrier concentration in silicon semiconductor,so as to realize the conductivity change and to design the terahertz modulator which can modulate frequency,terahertz band and phase.Its maximum modulation depth is 68.1% with band reconfigurability.Finally,the terahertz modulator designed in this paper is processed and tested.The measured data and simulation data are in good agreement and can be applied to the terahertz system.