Some basic characteristics of terahertz waves are as follows:

1, high transmittance: THz has good transmittance for many dielectric materials and nonpolar substances, and can be used for perspective imaging of opaque objects. It is an effective supplement to X-ray imaging and ultrasonic imaging technology, and can be used for nondestructive testing in the process of security inspection or quality inspection. In addition, THz has low transmission loss in dense smoke and dust environment, and is an ideal light source for imaging in complex environments such as fire rescue, desert rescue and battlefield enemy search.

2. Low energy: Terahertz photon energy is 4. 1 meV (millielectron volts), which is only one third of X-ray photon energy 107 ~ 108, which is lower than the bond energy of various chemical bonds. Terahertz radiation will not cause photoionization and damage the detected substance, which is very suitable for in vivo examination of human body or other biological samples. In addition, water has a strong absorption of terahertz radiation, so the radiation will not penetrate human skin, which is very safe for human body. Therefore, terahertz radiation is an ideal tool for medical detection of skin cancer and dental caries.

3. Fingerprint: THz band contains rich physical and chemical information. Most polar molecules and biological macromolecules are in the terahertz band, so according to these fingerprints, terahertz spectral imaging technology can distinguish the shape of the object, identify the composition of the object, analyze the physical and chemical properties of the object, and provide relevant theoretical basis and detection technology for drug control, counter-terrorism and explosive disposal.