Terahertz (THz) generator and detection

In the whole research process of electromagnetic wave, the research of terahertz wave belongs to a blank for a long time, which is the least known and least developed by far. But now, people are trying to make up the blank and develop terahertz better and better. The charm of terahertz wave originates from its multiple attributes, including electromagnetic field attribute, photon attribute and thermal attribute, which also attracts the attention of researchers in different fields and different countries, and also terahertz technology have been rated as one of the top ten technologies to change the future world by the United States. The multiple attributes of terahertz make it have broad application prospects in military and civil fields, such as medical imaging, astronomical observation, 6G communication, environmental monitoring and material analysis. It is no exaggeration to say that mastering terahertz technology means mastering the future. However, it is because of the multiple attributes of terahertz that the terahertz wave is difficult to be mastered. Although terahertz has been applied in some fields, controlling terahertz (such as generation and detection) is still an important issue. Nowadays, a variety of terahertz generation and detection technologies have been developed and continuously improved. In this paper, the main terahertz generation and detection technologies (including already practical and developing) are reviewed in terms of scientific and engineering principles, in order to provide a systematic and up-to-date reference for researchers in terahertz field.