Terahertz Imaging Progress at Capital Normal University

The progress on terahertz imaging at Capital Normal University in Beijing is presented. Our works on Terahertz Imaging include the active and passive imaging. For the active terahertz imaging, the pulse and continue wave terahertz imaging are studied, respectively. The active terahertz pulse imaging is based on the terahertz time-domain spectroscopy (THz-TDS). A practical focus-plane imaging system is built up based on the THz-TDS with the probe-beam-expanded electro-optical sampling and an infrared CCD imaging. The active terahertz continuous wave imaging is based on a CO2-laser-pumped terahertz coherent source and an uncooled bolometer array of terahertz camera. The active terahertz polarization imaging and wave front imaging is developed. For the passive terahertz imaging, the low frequency of radiometers are used to detect the point-to-point beam-scanned terahertz signal by the optical focusing and scanning system so that the passive THz imaging is realized for the security inspection of human body. The related components and image processing methods are studied and used for the improvement of imaging speed and resolution. The research on THz imaging technology at Capital Normal University is opening up a potential application in the field of non-destructive testing and security inspection for the terahertz technology.