From: pcdhSpamMeSenseless@electrooptical.net   
      
   On 08/19/2016 03:19 AM, Lu Wei wrote:   
   > I am trying to solve a general but seems complicated problem: reflection   
   > and transmission of light, on an interface of general profile. For   
   > example, the light falls on a fuzzy glass. Fresnel's equation gives   
   > analytical results on flat surface, but on rough surface, how do I   
   > calculate the reflection and transmission? Is there any software that   
   > could do this?   
   >   
      
   Depends how rough.  If the height of the roughness is much smaller than   
   a wavelength, you can do it easily by Fourier optics--it's just a random   
   phase screen, and the spatial frequency spectrum of the scatter is the   
   same as that of the surface.  (There's a factor of 2 for reflection   
   since the phase difference is twice as large.)   
      
   If the surface is really rough, so that multiple scattering is   
   important, you pretty well have to do it numerically.  Breault Research   
   sells ASAP which can do stuff like that.   
      
   In the middle, there are probably physical-optics things you can do to   
   make a semi-analytical model.   
      
   Cheers   
      
   Phil Hobbs   
      
   --   
   Dr Philip C D Hobbs   
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