Theoretical investigation on broadband THz deflectors for femtosecond electron beam diagnostics

Streak cameras are commonly used to measure duration and temporal structure of subpicosecond pulses. The resolution of a streak camera system strongly depends on the slew rate of the deflecting element, which approximately equals to the product of the amplitude and operation frequency of the device. As a combination of high frequency and high gradient, THz-driven deflector based streak camera system has been proposed as an attractive tool to reach femtosecond scale or even higher resolution. This study contributes to this growing area of research by investigating four promising designs of broadband THz deflectors with central frequencies at 0.3 THz. The basic properties of each structure, a systematical method to analyze their multipole fields and the derived fields are presented.