With the development of terahertz technology, its unique advantages and great application prospects in many important fields, such as physics, chemistry, electronic information, life science, material science, astronomy, atmospheric and environmental monitoring, communication radar, national security and counter-terrorism, have gradually emerged. Terahertz wave transmission is an important part of terahertz wave communication system research. Terahertz wave has great transmission loss in free space, so it is difficult to guide and control it in a sense. In order to overcome this difficulty, there is an urgent need for a waveguide capable of propagating terahertz waves.
Terahertz technology was rated as one of the "Top Ten Technologies to Change the Future World" by the United States and ranked as the first of the "Top Ten Key Strategic Goals of National Pillars" by Japan. Terahertz generally refers to the electromagnetic wave with the frequency of 0. 1 ~ 10, which is in the transition area from macroscopic classical theory to microscopic quantum theory and from electronics to photonics. Higher than microwave and lower than infrared in frequency; Energy is between electrons and photons. Because of this cross transition region, it is not completely suitable for optical theory to deal with it, nor is it completely suitable for microwave theory to study it. So before the 1990s, it was once "forgotten", so it was called "terahertz blank".
At present, countries have accelerated the exploration of this only under-studied band and set off a wave of terahertz research. Then, as the "expander" of the fifth-dimensional battlefield space, what are the specific applications of terahertz in the military field? Let's take a closer look.