Directivity of a plasmonic dipole optical antenna

Metallic plasmonic structures can modify the EM wave distribution and convert free-space propagation infrared light to localized surface plasmonic resonance (SPR). This can effectively function as an optical antenna and thus can enhance the performance of optical devices such as detectors and lasers. Most of the reported optical antenna devices are not closely interacted, which doesn´t take full advantages of optical antennas. In addition, there is very few report on important antenna properties such as far-field pattern and antenna directivity. In this paper, we report a closed coupled plasmonic antenna and quantum dot infrared photodetector (QDIP). The plasmonic antenna directivity is measured and analyzed.