THz quasi-near field focal plane imaging

A terahertz (THz) quasi-near field real-time imaging system is proposed. Using this approach, not only the consumption of experimental time can be dramatically reduced, but also the resolution of the imaging system is improved to the magnitude of sub-wavelength of THz waves. A metallic plate with sub-wavelength air hole arrays is imaged by using the system and the microstructure of the sample can be clearly obtained in its THz image. Due to the filtering characteristic of the sample, variances of its THz images can be distinctly observed at different THz frequencies. It is believed that the THz quasi-near field focal plane imaging system should have tremendous potential applications in THz microscopy field.