The low-cost thermal infrared ‘THz-Torch’ concept (referred to here as ‘THz-T’) was first
introduced over a decade ago, and since then the associated ‘over the THz horizon’ thermal infrared
(10-100 THz) implementation technologies have continued to advance. While short range secure wireless
communications links have received a great deal of attention, material spectroscopy has only briefly been
introduced in a short conference abstract. Here, for the first time, we explore in depth the basic concepts
behind THz-T spectroscopy. Moreover, when compared to the unvalidated results within our previous work,
we demonstrate an enhanced experimental THz-T spectrometer. A detailed thermal noise power link budget
model for both the transmission and reflection modes of operation has been undertaken and independently
validated. As a proof of principle, a diverse array of different material types has been characterized. This
includes glass sheets, semiconductor wafers, ceramic plate, plastic tape, plastic sheets, as well as polymer
and cotton paper banknotes. THz-T technology has the advantages of hardware simplicity and low cost
non-destructive testing for ubiquitous applications.