Review on Photoconductive Antenna Design from Conventional to Microstructures

Hemant Kumar

Abstract

Semiconductors possess many diverse phenomena under terahertz-frequency electromagnetic radiation (THz). This is due to the fact that the energy of THz photons is at quite large scales in case of bulk and low-dimensional materials and devices. With regard to broadband THz sources, various inorganic crystals such as ZnTe/GaP/GaAs/GaSe/DAST/LiNbO3 have been used which are pumped by femtosecond laser pulses. These pulses are combined with field-resolved detection through electro-optic sampling using similar crystals. Photoconductive devices have been the most successful method to generate terahertz radiation. Terahertz technology has witnessed a surge of new photoconductive antenna designs to increase the laser to terahertz conversion efficiency in a cost effective manner. The earliest design comprised of a simple strip line and bow-tie structure where the laser was focused on a small area. In this review article, research on conventional and current trends in photoconductive antenna design is presented with focus on microstructure devices that increases the effective excitation area of the antenna and utilize the incident laser power more effectively.

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