The pursuit of next-generation technologies places a premium on producing increased speed and efficiency with components built at scales small enough to function on a computer chip.
One of the barriers to advances in "on-chip" communications is the size of the electromagnetic waves at radio and microwave frequencies, which form the backbone of modern wireless technology. The relatively large waves handcuff further miniaturization.
Present on-chip optical communication technology uses near-infrared light, but visible wavelengths would allow system miniaturization and higher energy confinement. Towards this end, we report a nanoscale wireless communication system that operates at visible wavelengths via in-plane information transmission. Here, plasmonic antenna radiation mediates a three-step conversion process (surface plasmon → photon → surface plasmon) with in-plane efficiency (plasmon → plasmon) of 38% for antenna separation 4λ0 (with λ0 the free-space excitation wavelength). Information transmission is demonstrated at bandwidths in the Hz and MHz ranges. This work opens the possibility of optical conveyance of information using plasmonic antennas for on-chip communication technology.