Studies On Functional Devices Based On Magneto-Optic Materials At Terahertz Frequencies

In this paper,a new metal-dielectric-semiconductor-dielectric-metal waveguide structure(MDSDM)in terahertz band is proposed.The dispersion characteristics of its equivalent structure(MDSM)model are systematically studied,and its theoretical analysis and numerical simulation are carried out.Finally,we design a MDSDM symmetrical waveguide composed of tapered waveguide,uniform waveguide and tapered waveguide to realize bidirectional capture of electromagnetic wave(bidirectional rainbow capture),and achieve the function of "releasing" the previously captured electromagnetic wave by enhancing the external magnetic field.That is to say,the bidirectional process of storage and release of electromagnetic wave is realized.It is very important for optical communication,optical acquisition,optical signal processing and enhancement of non-linear optics.The results show that in our MDSDM waveguide,when the semiconductor thickness decreases,the cut-off frequency of the SMPs dispersion curve increases accordingly.Therefore,the change of the dispersion characteristics of SMPs in the waveguide can be achieved by adjusting the semiconductor thickness.At the same time,the dispersion curve of SMPs varies significantly according to the intensity of external magnetic field.In this MDSDM symmetrical waveguide structure,the group velocity of SMPs along the direction of electromagnetic wave propagation will gradually be smaller,the slow wave effect will appear.The group velocity of SMPs can even be reduced to zero,and electromagnetic waves of different frequencies can be "trapped" in different places.That is to say,"trapped rainbow" can be realized.Finally,by enhancing the external magnetic field,when the external magnetic field is larger than a certain value,the captured electromagnetic wave will continue to propagate along the waveguide direction,thus realizing the electromagnetic wave release process,which has been proved by numerical and simulation.