Apparently, nano scale Yagi-Uda antenna can be used to direct optical wave, which makes sense considering light is just high frequency wave, much much higher than radio wave. For those not into radio, antenna optimal for higher frequencies are smaller, so one that can emit or receive optical light would be nanoscale like this.
Naturally, I’d wonder what kind of SWR they were getting. (SWR: Standing Wave Ratio — when you put in energy into antenna from the transmitter, part of energy comes back. 1:1, which means same level of wave coming back to radio is considered optimal, and anything higher than 1.5:1 are generally considered bad. It can potentially destroy the transmitter…)
Wonder if they can make Hentenna version of nano antenna.