A 200 GHz Fully Integrated, Polarization-Resolved Quasi-Optical Detector Using Zero-Bias Heterostructure Backward Diodes

We report the design, fabrication, and prototype demonstration of a 200-GHz polarization-resolved quasi-optical detector employing monolithically integrated zero-bias heterostructure backward diodes (HBDs). In this design, polarization resolution is achieved by orthogonally integrating the detectors with a planar dual-polarization annular-slot antenna. The detector chip was fabricated and mounted on an extended hemispherical Si lens to enhance antenna efficiency in the millimeter-wave to terahertz region. The responsivity and radiation patterns of the detector were characterized experimentally; good agreement with theoretical calculations was obtained. By measuring the outputs of two orthogonal HBDs as a function of the polarization angle of the incident wave, the planar detector detects intensity and resolves polarization. On the basis of the polarimetric measurement, we further demonstrate the polarization imaging capability of the proposed detector by using it as an imaging system. The detector is promising for developing terahertz polarimetric sensors and imaging arrays in chemical sensing, biomedical imaging, and radio astronomy applications.