Nanoscale electronics and photonics are among the most promising research areas providing functional nano-components for data transfer and signal processing. By adopting metalbased optical antennas as a disruptive technological vehicle, we demonstrate that these two device-generating technologies can be interfaced to create an electronically-driven self-emitting unit. This nanoscale plasmonic transmitter operates by injecting electrons in a contacted tunneling antenna feedgap. Under certain operating conditions, we show that the antenna enters a

This supplementary material provides additional details about thermal effects observed in optical rectennas, and describes the observed correlation between the photocurrent and the nonlinearity of the conductance when irradiated with increasing laser intensities. I. THERMAL EFFECTSThermal effects can drastically influence the conduction properties of a laser irradiated tunneling jonction as reviewed by S. Grafström in Ref. [1]. Among possible processes resulting from photon absorption in the metal and subsequent Joule heating, let us mention thermal expansion of the gold leads, thermally-assisted field emission and thermovoltage arising from a temperature difference of the two sides of the rectenna feedgap when the laser is irradiating either one [2]. While it is difficult to completely rule out a potential heatrelated increased conductance in the results shown in the main manuscript, heat processes are providing well defined characteristics when the sample is scanned through the focus such as a contrast reversal of the current [3]. We did observe evidence for thermal currents in a rectenna consisted of an electromigrated Ti/Au stack. The ∼5 nm thick Ti layer acts a seed layer between the glass substrate and the gold layer. In the main manuscript, a Cr layer was systematically used instead of Ti and the results discussed below were never reproduced with Cr/Au rectennas. II. OPTICAL RECTIFICATIONWithin the assumptions discussed by Mayer and co-workers in Ref. [6], the classical picture of the rectified current is given by AbstractWe introduce strongly-coupled optical gap antennas to interface optical radiation with current-