Spectrometer based on parallel-plate waveguides utilizing abnormal transmission.

We designed a new, simple device based on parallel-plate waveguides (PPWGs) utilizing abnormal transmission to achieve the analogous function of a terahertz spectrometer. The phase gradient of the PPWGs is π/mm, and the designed wavelength is 0.3 THz. When abnormal transmission occurs, the position of outgoing light changes with the wavelength of the incident light with a quadratic function relationship, which can realize the terahertz spectrometer. The effect of different polarization was verified to be negligible when the polarization angle was 0-10°. The PPWG-based spectrometer has the advantages of simple structure and easy fabrication and can further help the development of terahertz technology.