How to illustrate ideal refraction using cycles? 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.
Setup:

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?
Sample Blend file -
LuxRender shows refraction correctly.

Install LuxRender (currently support 2.82 and 2.83)
Setup a model with a refraction shader just like for Cycles
Render!


Sample Blend file -