Upon looking at some radiation levels higher than Microwaves, I have come across "Terahertz radiation". According to the article, there are numerous ways to generate such radiation, and that brings questions to me.
My confusion lays in how it is different (if it is!) from a heating fan emitting infrared radiation (simple), or an LED emitting visible green light, or a flashlight emitting various spectral frequencies. Are those examples emitting Terahertz radiation? I would hypothesize that is, but can see no reference to light being called "Terahertz radiation" even though it is radiating.
Although I am unsure if the technologies listed in the article can go above infrared in to visible light, but assuming so, would it emit "light" (in the respective frequencies)? How would this be different than an ordinary visible light emitter? At that point is it no different from an "ideal" colour changing LED?