Enhanced terahertz photoconductive antenna based on metal array plasmon resonance
KONG Jiao1, ZHONG Shun cong1,2*, YAO Hai zi1, HUANG Yi1
(1.Laboratory of Optics, Terahertz and Non destructive Testing & Evaluation, School of Mechanical 
Engineering and Automation, Fuzhou University, Fuzhou 350108, China;
2.Fujian Key Laboratory of Medical Instrument and Pharmaceutical Technology, Fuzhou 350108, China)

Abstract: Aiming at the low output power of conventional terahertz photoconductive antenna, a terahertz photoconductive antenna based on metal array plasmon resonance enhancement was designed to improve the output power of terahertz photoconductive antenna. The physical field of electromagnetic wave and semiconductor were analyzed theoretically and the terahertz photoconductive antenna model was established. The simulation experiment was carried out by COMSOL multiphysics finite element software. The optical absorption of the 800 nm laser at different pitches and heights of the metal array plasmon resonance structure was calculated and the optimized structure of the plasmon resonance enhancement structure was obtained. Then the photocurrent of this designed plasmon resonance terahertz photoconductive antenna was calculated, as well as the conventional terahertz photoconductive antenna. The results indicate that the designed metal array plasmon resonance enhanced terahertz photoconductive antenna is about 20 times stronger than that of the conventional terahertz photoconductive antenna, which provided the basis for the enhancement of plasmon resonance terahertz photoconductive antenna.

Key words: terahertz photoconductive antenna; plasmon resonance; photocurrent