Research Progress of Micro-Nano Optical Structure and Terahertz Radiation Generation Technology

Terahertz *THz) technology plays a significant role in basic research and industrial applications. However, the wide application of it is still limited by efficient and compact THz sources, especially in the 0.5-2.0 THz band. Currently, researchers have adopted various technologies to generate THz radiations, in which the optical based methods are the most important means. In this paper, first, for the THz pulse and continuous waves, the THz radiation generation mechanism based on the photoconductivity effect and nonlinear optical difference frequency are summarized with the application of micro-nano optical structures to improve the conversion efficiency from the pump light to THz radiation. Then, two enhancement situations of the metal nano -optical antenna by enhancing the local electric field of the pump light to improve the THz radiation efficiency, and the metal nano-optical antenna as the THz radiation source are analyzed. Finally, the use of other optical micro-nanostructures in the generation of THz radiation have been outlooked, especially the enhancement effect of novel physical phenomena, such as Mie resonance, non-radiative mode and bound state in the continuous domain supported by all -dielectric optical antennas.