Terahertz waves, T-rays, and T-birds

Summary form only given. Optoelectronic generation of terahertz bandwidth electromagnetic pulses has made access to the previously hard-to-reach far-infrared region of the electromagnetic spectrum possible. Within about ten years, this technique has evolved from a lab curiosity to a technology that now has tremendous promise for applications. This shift is partially driven by the advent of compact, practical, and cheaper femtosecond pulse lasers. In addition, advances in the terahertz time-domain technology itself have resulted in its use not only for spectroscopy and science but also for terahertz T-ray imaging and many industrial applications. This tutorial will review the advances in technology that have been made, the development of T-ray imaging, and novel detection techniques. In addition, applications of terahertz waves and T-ray imaging in spectroscopy, far-infrared imaging, gas monitoring, industrial quality control, packaging, and moisture measurements will be discussed. We will also find out how far we are away from the T-bird, the fax-machine-sized terahertz instrument introduced in Tom Clancy's novel.