Characterization of High-power Narrow-band Terahertz Radiation Generation Using Large-aperture Photoconductive Antennas

High-power narrow-band terahertz (THz) radiations emitted from a biased large-aperture photoconductive antenna triggered by multiple-pulse trains is studied.The effects of the finite lifetime and transient mobility dynamics of photogenerated carriers in the analysis are included.THz waveforms are calculated from the saturation theory of large-aperture photoconductive antennas,and comparisons are made between single-pulse and multiple-pulse satruation proterties of THz emission from SI-GaAs and LT-GaAs emitters.The results show that the saturation at high fluence density with the interpulse spacing longer than the carrier lifetime can be avoided by mulitiple-pulse trains excitation large-aperture photoconductive emitters.