Love the (original) opening sentence of this article <https://arstechnica.com/gadgets/2023/07/light-based-lifi-promises-amazing-wireless-speeds-just-not-through-walls/>: Light is almost certainly the fastest thing around. So it makes sense that "light-based wireless communications," or LiFi, could blow the theoretical doors off existing radio-wave wireless standards, to the tune of a maximum 224GB per second. A correction/clarification immediately follows, but it’s clear the writer didn’t quite grasp that both visible light and radio waves are propagated by exactly the same particles--photons--travelling at exactly the same speed. What is true is that, as the frequency of the photons increases, so does their information-carrying capacity. This is why we have digital broadcasts (TV particularly), mobile phone/data services and our own wi-fi networks all moving to higher and higher frequencies. The downside is, as the frequency of a photon increases, so does its energy. And so it tends to react more and more with (i.e. be absorbed by) various bits of matter that it might encounter--such as the walls of buildings, or even the air itself. This tends to limit the useful range of these communication bands.