Research And Design Nonreciprocal Device Based On Magneto-optical Material

Photonic crystal composed of magneto-optical materials or surface plasmonpolaritons of magneto-optical material, can support one-way transmission modeswith external magnetic fields, magneto-optical materials becomes anisotropicwith permeability tensor or permittivity tensor, breaking time-reversalsymmetry or space symmetry of the system. These nonreciprocal devices has animportant application prospect and research value in optics and other fields.In this thesis, we first analyze the permeability tensor of magneto-opticalmaterials with external magnetic field, investigate the band properties of thetwo-dimensional magneto-optical photonic crystal by the plane wave expansionmethod, and the influence of dielectric cylinder radius and external magneticfield intensities on band gap have been analyzed. For the surface plasmons, weanalyzed dielectric constant of semiconductor according to Drude model briefly,studying the TM mode dispersion relations according to unfold the Maxwell’sequations.On the basis of the abovementioned research, a hexagonal ring resonatorstructure based on one-way magneto-optical photonic crystal is proposed,profiting from the one-way edge mode of magneto-optical photonic crystal, theproposed resonator structure possesses the characteristics of high quality factor,and controllable one-way rotating direction. A three port circulator is proposedby the cavity coupling with photonic crystal waveguide. Analysis the cavitysize impact on circulator system through simulation.This thesis also proposes a terahertz one-way waveguide based onstructured semiconductor magneto plasmonics, and set a90°bend in thewaveguide structure. With this one-way waveguide, a T-type beam splitter isproposed, which has characteristics of simple structure and small size. Thesimulation results show that the efficiency of total transmission is above99%.In summary, the resonator and circulator based on magneto-opticalphotonic crystal and one-way waveguide based on structured semiconductor magneto plasmonics provides a new way of thinking on non-reciprocalfunctional devices.