A full wave analysis of a terahertz-pulse generation for wide-bandgap photoconductive antennas using a field-carrier transport scheme

A full wave analysis of generating terahertz pulses from photoconductive antennas is described. By using a three-dimensional finite-difference time-domain (FDTD) method incorporated with semiconductor carrier transport equations, photocurrents and wave propagation inside photoconductive semiconductor switch (PCSS) antenna can be calculated. The numerical result shows nonlinear behavior of terahertz-pulse generation following laser induced activation of the PCSS. This attributes to the transient field redistribution, carrier generation characteristics, and field acceleration. A comparison of the radiation characteristics from using this simulation approach and from the previous measurement data is in agreement, providing a proof of concept. The frequency spectra of radiation were found in the frequency range of 0.1-4.0 THz.