Input Power and Effective Area in Terahertz Detector Measurement: A Review

The field of terahertz (THz) science and technology research area have been exponentially growing recently, motivated by the increasing demand for safer security imaging, better quality control within manufacturing industries, space and astronomical investigation, biomedical diagnostics, and larger communication bandwidth. The THz waves detection mechanism is one of the critical components in developing a high efficiency and high sensitivity THz communication system. This paper reviews the principle and instrumentation of THz optical metrology for the precise and accurate characterization of THz detectors in the range of 0.1 THz to several THz. In this context, we individually discuss the determination of radiation input power and effective area followed by a survey of THz optical measurement methodology used in the state-of-the-art THz detectors. In addition, challenging issues remaining in the THz detector measurements are provided. This paper sets out a guideline to address the main concept behind the THz detector measurement as well as their challenges and opportunities. Additionally, useful insight is given through a summary of available power meter instrumentation for THz input power calibration.