Abstract

The term terahertz (THz) became one of the most popular words in science nowadays. Why? And what is it? Why more and more scientific books, articles, and conferences are being devoted to this topic all over the world? Why THz centers are being established at many universities and laboratories? Why do THz programs appear in different countries? The article brings you short answers to these questions. It explains what THz radiation is and what a so-called THz gap is. We touch the peculiarities of the THz radiation and mention its important applications. Then we consider the state of the art in THz science. As it is impossible to cover all the scientific and technical aspects of the THz science in the short review, therefore we only touch the semiconductor nanostructure-based devices and technologies in two most important fields; namely, we will look at THz sources and detectors, paying particular attention to their differences from conventional optical devices. And we hope that readers of this article will become more familiar with THz science and they will also try to find their own ways of implementing THz radiation into their scientific activities.