Exotic IMPATT oscillator for terahertz thermography: feasibility studies in hepatic tumor detection

Abstract

Hepatic carcinoma is a major type of malignant tumor that needs a novel non-invasive/minimal invasive method for its early diagnosis. This paper for the first time reports a new scheme of diagnosis of hepatic tumor by studying the corresponding terahertz (THz) thermographs. A solid-state source of THz radiation (IMPact-ionisation avalanche transit time oscillator), capable of working at room temperature, is proposed in this paper and the THz non-linear characteristic of the device and system are studied through an in-house developed quantum modified classical drift diffusion simulator. The validity of the model is also established by comparing the results with experimental observations. The model includes temperature effects, quantum size effect, lattice phonon scatterings, and noise study. A COMSOL-based THz-thermograph model is further developed and a comparative analysis with those of microwave thermographs is reported. To the best of authors� knowledge, this is the first report on studying the prospects of an exotic type non-invasive terahertz <p+-n-n+> radiation source for use in T-ray thermography studies of hepatic tumors detection with two sets of different radiation exposure.