Terahertz Reflection-Mode Biological Imaging Based on InP HBT Source and Detector

This paper presents the development of an oscillator and a detector based on InP HBT technology operating near 300 GHz, and their application to terahertz reflection-mode imaging. The fabricated fundamental-mode common-base (CB) crosscoupled oscillator exhibits a peak output power of 5.3 dBm at 305.8 GHz, and the CB direct detector shows a responsivity higher √ than 40 kV/W and noise equivalent power lower than 35 pW/ Hz for a frequency range of 270-345 GHz. The imaging system employing the fabricated circuits as the signal source and detector was characterized for the resolution and dynamic range, and then, successfully applied for imaging various biological samples. The results show that low-power terahertz reflection-mode imaging based on solid-state electronic sources and detectors based on a commercial semiconductor technology is promising for various biomedical imaging applications.