I’m still learning about quantum field theory, so I am probably wrong, but I think this idea presupposes you can “trap” an excitation that arises in a quantum field.
Why not? We have reflective materials that these excitations bounce off, right?
As far as I understand, we have not managed to create perfectly reflective surfaces (and there are none in nature that we know of).
What purpose would that help? We do have CMB and a lot of light emitted from long ago from stars we get today. Are you specifically after the light from our sun from 4b years ago?