光导间隙对光导开关辐射太赫兹脉冲特性的影响

In this paper we investigates the influence of photoconductive switch gap to the THz radiation characteristics, illustrated that when the gap is reduced to submicron order,the peak of theTHz pulse is more higher. Based on full-wave electromagnetic field model theory，we carry on strict theoretical analysis to the radiation process of photoconductive switch with the finite difference time domain (FDTD) method. The result shows that when the nano titaniumoxide line fabricated with atomic force microscope tip induced anodic oxidation replaces traditional air photoconductive gap, the movement time of the light-fresh carrier is shortened and the response speed of the switch is improved, the gap also avoids being penetrated by a greater voltage so that the peak of THz pulse could be enhanced.