Well, radio waves consist of light, albeit outside of the visible spectrum. It is certainly possible to transmit signals using visible light (see Li-Fi), althou

Well, radio waves consist of light, albeit outside of the visible spectrum. It is certainly possible to transmit signals using visible light (see Li-Fi), although visible light transmissions could be jammed using the same techniques. Might not be ideal for covert communication though, since you could see someone broadcasting without any special equipment.