Is this possible? Will there be any interesting time-related incidents that this can produce?
Ofcourse light does slow down, on its own. Light is an electromagnetic wave, that propagates wit varying electric and magnatic fields.
The speed of light in a medium depands on:
1. Permeability of the medium
2. Permitivity of the medium.
All other media have these values higher that those in space. This means, light has the maximum speed in space. And, in say water or glass, it slows down on its own
For a Photon which evidently moves with the speed of light, consider this---
Time stands still for it.
That is, for a photon it's formation and ultimate absorption is instantaneous, since it is traveling at the speed of light.
Distance has no meaning for it.
Whatever distance a photon may travel according to other frame , but in it's own frame it does not travel any distance at all, as all the distances are compressed to lesser than a point for the photon's point of view.
May we say that for a photon it does not exist as it exists for no time and it travels no distance. Or in other way- time does have no meaning or may we say that it does not exist for a PHOTON.
So a photon cannot be made to travel slower than the speed of light in vacuum as that will mean the existence of time and distance for it.
The light (photons) have been stopped at its tracks in real time without in any way affecting the time.
Slowing Light s easy. Just pass it through something denser than vacuum ( water for example). Relativity states that no particle can travel at or more than the speed of light but this limitation only holds in VACUUM . In dense media, like water, light slows down and hence it is possible for a particle to travel through water (for e.g.) at a speed speed faster than light. And if this particle is charged then it emits light radiation otherwise known as Cherenkov Radiation . This is a well known phenomena.