The invention discloses a terahertz
isolator device of a magnetic surface
plasma waveguide and a control method thereof. The asymmetric and periodic surface
plasma waveguide is formed by a
metal wall and a
semiconductor indium antimonide pillar array. By exerting an external
magnetic field under low temperature, the
indium antimonide shows the revolving electrical property, and the structure can generate a magnetic surface
plasma mode, so that the function of unidirectional isolation transmission of the terahertz wave can be achieved. The unidirectional transmission working frequency range is higher than 1THz, the bandwidth is larger than 80 GHz, the isolation reaches 90dB, the
insertion loss is lower than 0.25dB, and tuning on the working frequency range can be performed by controlling the external
magnetic field strength. Under the temperature of 186K, the frequency of the external
magnetic field can be adjusted to 0.7T from 0.1T, and the central working frequency of a unidirectional transmission
frequency band of the device can be tuned to 1THz from 1.42THz. The terahertz
isolator is low in loss, high in isolation, tunable in
broadband and capable of reducing echo and scattered noises in a terahertz application
system and improving
transmission quality of the terahertz beam.