ABSTRACT
The exploration of veiled fields has been the driving force for new scientific discovery and the development of novel techniques. The very far-infrared (FIR) spectral range remains one of the least explored regions of the electromagnetic (EM) spectrum. Until the 1970s, the terahertz (THz) range (100 GHz to 3 THz, 3000-100 μm) was called THz gap owing to the lack of efficient sources and detectors (Gallerano and Biedron 2004; Tonouchi 2007; Zhang and Xu 2009; Zhang et al. 2005) for this region. Recently developed powerful sources and sensitive detectors, operating in the THz spectral region, are aimed at rapidly shrinking the THz gap. Such developments have led to the introduction of several industrial products spanning diverse areas including biomedical application.
