Active imaging with incoherent sub-terahertz radiation in smoky environments

Abstract

This paper describes the capability of active imaging with sub-terahertz (THz) illumination in a smoky environment. The developed illuminator consists of nine uni-traveling-carrier photodiode modules and an optical circuit that generate incoherent sub-THz waves with a center frequency of 833 GHz. Tests on a target at a distance of 115 cm showed that imaging with incoherent sub-THz illumination provides a clear view in black, dense, and high-temperature smoke, for which the visibility was 30 cm for visible light. These results indicate that sub-THz active imaging is an effective way to ensure visibility in fire environments such as a space filled with heavy smoke.