Optical antennas for quantum emitters

Optical antennas are nanoscale versions of radio antennas and have emerged in recent years as an enabling technology for nanophotonic devices. In particular, they open interesting avenues to control and enhance the emission of single quantum emitters such as molecules and quantum dots. The ability to modify transition rates, polarization and angular radiation patterns of fluorescence could improve the performance of single-photon sources and ultrasensitive biosensors. In this contribution, we review the state of the art of optical antennas, focusing especially on the activities of the Molecular Nanophotonics group at ICFO. We describe the possible resonant modes of nanorod optical antennas, address the controlled coupling of single emitters to a nanoantenna with two different experimental approaches, and show the realization of optical monopole and Yagi-Uda antennas to direct the emission of single emitters.