why does a light bulb need a vacuum
Incandescent light bulb Early lamps, and some small modern lamps used only a vacuum to protect the filament from oxygen. This however increases evaporation of the filament, albeit it eliminates the heat losses.
Photon A photon is a type of elementary particle, the quantum of the electromagnetic field including electromagnetic radiation such as light, and the force carrier for the electromagnetic force (even when static via virtual particles). The photon has zero rest mass and always moves at the speed of light within a vacuum.