Efficient and wideband horn nanoantenna

In this Letter, we present the design of a horn nanoantenna working at near-IR frequencies. The proposed layout consists of an Ag-air-Ag nanotransmission line terminated in a tapered horn. The antenna design is validated through proper full-wave numerical simulations, taking into account actual dispersion and losses of the involved materials. The numerical results show that the designed nanohorn is matched over a broad range of frequencies (more than 50% of fractional bandwidth) and radiates efficiently in the same frequency band ( the realized gain is greater than 10 dBi). Such promising results may find application in different technical and scientific fields, ranging from smart lighting to optical wireless communications. (C) 2011 Optical Society of America