Multifunctional magneto-metasurface for terahertz one-way transmission and magnetic field sensing

A magneto-metasurface is demonstrated for one-way transmission of terahertz (THz) waves and magnetic field sensing. Due to the magneto-optical effect and the asymmetric structure of the transmission system, magnetoplasmon mode splitting for forward and backward THz waves and one-way transmission has been observed in this magneto-metasurface. Significantly, the resonance of the magneto-metasurface has been found that can remain at 0.750 THz at a temperature of 218 K, performing as a stable isolator with an isolation of larger than 30 dB within a magnetic field disturbance from 0.23 to 0.35 T. Also, since the resonance of the magneto-metasurface can be tuned by the different external magnetic fields at a temperature that is higher or lower than 218 K, the magneto-metasurface can work as a highly sensitive magnetic field sensor. The sensitivity of this device reaches S=513.05  GHz·T(-1) when T=230  K. This multifunctional magneto-metasurface has broad potential in THz application systems.