Abstract

With a frequency exceeding a trillion cycles per second, the terahertz (THz) band occupies an extremely large area of the electromagnetic spectrum between the infrared and microwave bands. This far-infrared (IR) region is important because of the rich physical and chemical processes with spectrographic footprints within it. As late as the 1970s, Fourier transform spectroscopy, which uses an incoherent blackbody source and a cryogenic bolometric detector, was the important spectroscopic technique in this region, but its performance was hampered by the lack of bright sources. The situation changed dramatically with the advent of THz time-domain spectroscopy in the late 1980s.

© 2001 IEEE