Investigation of the Carrier Concentration and Laser Peak Intensity on the Terahertz Pulse Generated by Photoconductive Antennas Based On LT-GaAs

The possibility of terahertz generation has been investigated from a photoconductive switch based on GaAs, gated bya femtosecond laser. The emission properties of photoconductive antenna (PCA) with low-temperature-grown (LT)GaAs have been studied. In such GaAs materials presence of the charged defects induces a redistribution of theelectric field between the antenna electrodes. This effect has a huge influence on the amplitude of the radiatedterahertz field. In this work we demonstrate that carrier concentration enhances radiation power. Results obtained as afunction of the laser excitation power (with 100 fs rise time and 1KHz repetition rate) and carrier concentration arediscussed and a comparison of the performance of these devices with a conventional antenna-type (dipole) emitter isgiven.

کلیدواژه ها:

Photoconductive antennas (PCAs) ، LT-GaAs ، THz radiation ، Femtosecond laser