How can a scene be setup to illustrate ideal refraction? The desired result is something like this (courtesy wikipedia):
In this cycles setup, a light projects nearly straight rays out (see Making a Laser in Cycles - Straight Beam of Light?). A plane is setup with a refraction shader. When the light passes through it, the outgoing rays are much more diffuse than the incoming rays.
Plane refraction shader:
The result with the light rays::
How can the result be improved? Can the strength of the ray be increased after it hits the plane? Can the desired result be generated?