Terahertz Radiation Generated by Laser Induced Plasma in Photoconductive Antenna

To theoretically analyze the spectral characteristics of terahertz (THz) electromagnetic radiation generated by photoconductive antennas, the paper proposed a model by considering laser induced plasma in photoconductive antenna. At a bias voltage, plasma oscillation generates Langmuir wave that propagates in the inhomogeneous plasma in the direction of density gradient, and is converted to THz radiation after a converse zone. The influence factors of the bandwidth and peak frequency are analyzed by the model and testified by experiment.