High performance terahertz source using ion implanted photoconductive antenna

In this work we show that improved performances of small-aperture terahertz antennas can be obtained using an ion implantation process. Our photoconductive materials consist of high resistivity GaAs substrates. Terahertz pulses are generated by exciting our devices with ultrashort laser pulses. Ion implantation introduces nonradiative centers which reduce the carrier lifetime in GaAs and modify the shape of our terahertz pulses. The introduction of charge defects also induces a redistribution of the electric field between the antenna electrodes. The overall process is optimized to better control the dynamical field screening effect which has a huge influence on the amplitude of the radiated terahertz field. Results obtained as a function of the laser excitation power is discussed and comparison of the performance of these devices with conventional small-aperture antennas is given.