High-Quality Continuous-Wave Imaging with a 2.53THz Optical Pumped Terahertz Laser and a Pyroelectric Detector

A cw terahertz (THz) transmission imaging system is demonstrated and a high-quality THz image can be obtained using a pyroelectric detector. The factors that affect the imaging quality, such as the THz wavelength, spot size on the sample surface, step length of the motor, and frequency of the chopper, are theoretically and experimentally investigated. The experimental results show that the maximum resolution of the THz image can reach 0.4 mm with the THz wavelength of 118.8 μm, the spot size of 1.8 mm and the step length of 0.25 mm.