Springer Science+Business Media Singapore 2016. All rights reserved. An overview of the field of optical plasmonic antennas is presented in this chapter. After a brief introduction and historical review, the theory of surface plasmon polaritons which leads to a set of overall observations as to the requirements and restrictions placed on the operation of plasmonic waveguides and antennas is presented. Both a single metal-dielectric interface and two interfaces between a metal sheet with dielectrics on either side are considered. In the second section the physical principles of operation and mathematical design criteria are presented for several common optical antennas including on-surface metallic structures and free standing particles. The third section covers the basic theory of aperture radiators along with a more detailed description of some popular designs. Current applications of optical nanoantennas are presented along with a discussion on some future directions in optical nanoantenna research.
