[Opto-Electron Eng, 2020, 47(5)] Research advances of high-resolution THz imaging based on terajet effect

Terahertz (THz) imaging technology has shown great advantages and potential applications in the fields of biomedicine, security, and aerospace, due to its low energy, high transmittance, wide bandwidth, and unique analysis abilities; while low spatial resolution restricts its further applications. Recently, a high-resolution, high-throughput, and broad-bandwidth THz imaging method has been proposed based on the terajet effect produced by dielectric structures with appropriate refractive index. The terajet beam can break through the restriction of the diffraction limit on the spatial resolution of the microscopic system without losing the energy and spectral bandwidth of the THz field. In this paper, firstly, a white-light nanoscopy based on photonic nanojet produced by microspheres is introduced, then the THz microscopy based on terajet effect produced by mesoscopic dielectric structures is reviewed. Finally, the prospect of THz high resolution imaging technology based on terajet effect is prospected.