Yagi-Uda nanoantenna in the near-field optical domain

An optical analogue of the well-established radio-frequency Yagi- Uda antenna, stands out by its effective unidirectional light emission and enhancement. Similar to radio wave and microwave antennas, their purpose is to convert the energy of free propagating radiation to localized energy, and vice versa. Optical antennas exploit the unique properties of metal nanostructures, which behave as strongly coupled plasmas at optical frequencies. Nobel metallic nanoparticles like Gold or silver with their plasmon resonances in the optical wavelength region can be used in a similar manner. Near-field coupling of quantum emitters to these particle plasmon resonances is used to redirect the light emission. Pursuing a brief introduction to the emerging field of opticalnanoantennas, here we review the effect of changing the dipole, director and reflector's radii on the directivity of Yagi-Uda nanoantenna in nearfield optical domain. The various aspects of the guiding properties of arrays of metamaterial or plasmonic particles, with a specific focus on Yagi-Uda nanoparticle models are investigated. In-depth analysis is performed on the transmission, reflection, and directive properties of nanoantenna