  Optical nanoantennas mediate near and far optical fields. Operating a
directional nanoantenna in transmitting mode is challenging as the antenna
needs to be driven by a nanosized optical-frequency generator, working at the
antenna resonance frequency and attached precisely to the antenna feed with a
correct orientation. Quantum emitters have been used as optical nanogenerators.
However, their precise positioning relative to the nanoantenna is a technical
barrier to the practical implementation. One unique source to drive nanoantenna
is the photoluminescence of the antenna material as the operation frequency
range corresponds to the electronic transitions in matter. Here, we exploit
plasmon-modulated photoluminescence (PMPL) as an effective optical source to
drive directional nanoantennas. We experimentally realize two technically
challenging theoretical proposals, namely, optical nano-spectrometer based on
Yagi-Uda nanoantennas and tunable broadband directional emission from
log-periodic nanoantennas. Using photoluminescence from the nanoantenna as an
optical source promotes practical implementation of transmitting optical
nanoantennas.
