An optical transmitter produces electromagnetic radiation (e.g., light) of at least one frequency (e.g., at a particular color frequency) by utilizing a resonant structure that is excited by the presence a beam of charged particles (e.g., a beam of electrons) where the electromagnetic radiation is transmitted along a communications medium (e.g., a fiber optic cable). In at least one embodiment, the frequency of the electromagnetic radiation is higher than that of the microwave spectrum.