Semiconductor THz microsensors based on ultrahigh-contrast T-shape patterned interferometers

A plasmonic interferometer consisting of a T-shape patterned semiconductor is investigated in THz regime. The microslit couples incident THz radiation into unidirectional SPPs waves, which are reflected by bilateral sidewalls and interfere with directly transmitted THz wave. The phase/amplitude of interfering SPPs waves can be effectively engineered by structural tuning, offering a flexible and efficient control over the shape of interference pattern. Spectral fringes with large amplitude and high-contrast have been demonstrated and permit Figure-of-Merit for intensity detection (wavelength sensitivity) up to 15255%RIU^-1 (160 um/RIU). The results could be promising for developing ultrasensitive biosensors and on-chip platforms.