Intense Terahertz Antenna Array with Interdigital Electrodes

Intense terahertz antenna array with interdigital electrodes
Lei Hou, Wei Shi*, Ming Xu, Yong Chen Department of applied physics, Xi’an University of Technology, Shaanxi, China, 710048
ABSTRACT
In this work a powerful terahertz antenna array with interdigital electrodes is fabricated, and the performance of one antenna unit is compared with a conventional resonant dipole antenna. The antenna unit has a better capacity of generating THz wave compared with a conventional resonant dipole antenna at the same bias electrical field and the same laser energy. However only 23 % of THz wave transmitted through the ceramic substrate of antenna array, if there is a hole drilled through ceramic substrate to release the THz wave, the THz amplitude of entire interdigital antenna array with 8 antenna units can be more than 10 times larger than that of resonant dipole antenna. To get this result, the pump beam is focused into a linear beam by a cylindrical lens to trigger the antenna array, and the linear THz wave is focused by a polyethylene lens before it reaches ZnTe crystal. Keywords: Terahertz antenna, antenna array, interdigital electrodes, resonant dipole antenna, GaAs

1. INTRODUCTION
Terahertz spectroscopy is of great scientific and technological interest in many fields, such as explosives and chemical detection [1], biology threat detection [2], quality control and non-destructive testing [3], material analysis and testing [4] etc. In THz TDS system, photoconductive antenna is often used as THz source. So it is very important to design and prepare stable and robust photoconductive antenna [5]. Although the structure and usage of the conventional largeaperture antennas are simple, the requirement of a bias voltage as high as 10 kV or more has limited their usage [6]. In this paper, we fabricated a photoconductive antenna array with interdigital electrodes on commercial SI-GaAs substrate and compared the performance of one antenna unit of the array with a

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