Technology demonstrators for low-cost terahertz engineering

There is no doubt that terahertz (THz) technology is rapidly growing in interest. Its frequency range lies in a commercially unexploited part of the electromagnetic spectrum. Front-end systems operating in the THz gap, i.e. frequency range between where the performance of conventional electronics falls off and that of photonics increases, have generally existed for expensive scientific applications and have relied on precision free-space (quasi-) optics and often cryogenic cooling. However, in order to move away from less profitable high-end applications, engineering solutions are needed to create a positive spiral of technological growth with more profitable ubiquitous applications. This review paper introduces recent examples of THz technologies that may have the potential for future commercial exploitation.