Enhancement effect on photoelectric conversion efficiency of plasmon-induced terahertz photoconductive antenna

The laser electric field distribution, carrier distribution and photoconductive current densities under different electric field intensities in low temperature grown GaAs (LT-GaAs) layer of photoconductive antenna (PCA) have been simulated by finite element method. When a plasmoninduced PCA is pumped by an 800 nm laser beam, the plasmon on the interface of air and LT-GaAs aids the conversion of more laser photons into photo-generated carriers and thus increases the density of the photo-current leading to a higher-power terahertz pulse. A quadratic function fitting relationship between the laser electric field intensity and the maximum density of photoconductive current has been obtained for the first time. On this basis, a plasmon-induced terahertz PCA has been designed and packaged using electron beam exposure technology. The enhancement effect on photo-electric conversion efficiency of plasmon in PCA is verified by comparing terahertz radiation spectra from conventional and plasmon-induced PCAs. The terahertz radiation properties of two kinds of PCAs fabricated on an identical LT-GaAs layer were evaluated by means of terahertz time-domain spectroscopy.

Automated summary

The laser electric field distribution, carrier distribution, and photoconductive current densities in the low temperature grown GaAs layer of a photoconductive antenna were simulated by the finite element method. The study also included designing and packaging a plasmon-induced terahertz PCA and evaluating the terahertz radiation properties of two kinds of PCAs using terahertz time-domain spectroscopy.