Enhanced terahertz magneto-optical Kerr rotation based on metasurface structure

A terahertz (THz) magneto-optical (MO) polarization rotator in reflective geometry was proposed based on metasurface structure. Combining MO material and microstructure brings new effects: (1) MO makes the classical structure of metasurface absorber becomes a polarization rotator; (2) Due to the resonance of the metasurface, Kerr rotation effect is significantly enhanced, of which rotation angle is over 90. and 5.3 times larger than the bare ferrite film. Moreover, the device can maintain an excellent performance when incident angle varies from 0 to 75 degrees. This work has broadly potentials for THz isolator, MO modulator, and polarization convertor in THz applications.