From: benj.fake@gmail.com   
      
   On 4/15/2020 3:49 AM, Ned Latham wrote:   
   > I was thinking about parallel-sided glass blocks, and their   
   > fascinating demonstration of refraction of light on both   
   > entry and exit, and it occurred to me that I've never seen   
   > or heard anything about the beam itself except that it's a   
   > little wider on exit than on entry.   
   >   
   > So I wondered: has anyone ever looked at the exit beam in   
   > sufficient detail to detect a spectrum or dismiss the idea?   
   >   
   Why would you assume exit beam is wider?  What if it's focusing down?   
      
   Consider a laser beam through the block, When you say looked at in great   
   detail what do you mean "great"? Generally the progress of say a single   
   mode laser beam through a material can be theoretically calculated to a   
   great deal of accuracy. Not saying there might not be some interesting   
   details found but generally classic theory is usually highly in   
   agreement with measurements.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)