Generation and detection of terahertz pulses from biased semiconductor antennas

We propose a simple model based on the Drude–Lorentz theory of carrier transport to account for the details of the ultrashort terahertz pulses radiated from small photoconductive semiconductor antennas. The dynamics of the bias field under the influence of the space-charge field from the accelerated carriers is included in the model. We consider in detail the optical system used to image the terahertz radiation onto the terahertz detector, and we calculate the frequency-dependent response of the detector. The proposed model is compared with several different experiments, each focusing on different parameters of the model. Agreement between experiment and model is found in all cases, supporting the validity of this simple and appropriate model.