Is stopping a single photon possible? I'm curious if it's possible to use some kind of "magnetic confinement" to essentially suspend a single photon?

 A: Asking if a photon could be "stopped"$^1$ in the traditional sense of "stopping", is not a well-defined question.
There exits no frame of reference where a photon can be considered stationary. And a photon has no charge, nor does it have a magnetic (or electric) dipole moment, and so it cannot be affected by a magnetic (or electric) field. So magnetic (or electric) confinement does not appear to be feasible.
Since a photon is massless it must travel at the speed of light, and this speed is invariant regardless of the motion of the source or observer.
Confining a photon to a small region in space is perhaps the closest one can get to achieving this, although the photon still moves at the speed of light in between collisions of the walls in this region.
This was achieved for individual photons by Nobel prize winner Serge Haroche.
In essence, this was done using what's called a high Q cavity that is essentially a box who's inside walls are reflecting mirrors. This cavity was able to store one photon for about $20ms$.
$^1$Unless it is completely absorbed at a point, at which point it ceases to be a photon anyway.
