Significant performance improvement of a terahertz photoconductive antenna using a hybrid structure†
A photoconductive terahertz antenna based on a distributed Bragg reflector, recessed nanoplasmonic grating and recessed electrodes is proposed in this paper. By use of the finite element method and full wave simulation, the effect of geometrical parameters on the transient photocurrent of a proposed photoconductive antenna is investigated. The recessed nanoplasmonic structure reduces the reflection of laser light to less than 1.5% from the surface of low temperature gallium arsenide in comparison with 29% for a conventional photoconductive antenna. According to the results, the distributed Bragg reflector in combination with recessed nanoplasmonic grating and recessed electrodes results in 5265% photocurrent peak enhancement in comparison to a conventional photoconductive terahertz antenna.