From: luweitest@address.invalid   
      
   On 2015-10-15 21:32, ggherold@gmail.com wrote:   
   >>>...   
   >> Yes I have the manual.  The situation I am considering is not common in   
   >> ellipsometry, because normally an optically semi-infinite substrate is   
   >> used. If the substrate have a thickness less than coherent length, then   
   >> it should be treated as an layer. But in my situation, that layer is too   
   >> thick (mm instead of normally nm), and laser is the light source, so the   
   >> reflection beams from front and back side actually split apart. So   
   >> interference may just happen at their intersection, and the signal   
   >> analyzer may get is the superposition of two incoherent lights and a   
   >> interfered light.  That seems really complicated.   
   >>   
   >> The measurement situation:   
   >> http://postimg.org/image/44b1ze9hb/   
   >   
   > Can you put a small wedge on the substrate?   
   > Roughen (sand blast) the bottom to get rid of the reflection?   
   >   
   > Careful placement of a bit of black tape to block the second reflection.   
   > (Yeah that's hard when the angle is changing...)   
   >   
   Yes actually roughening the bottom side is what I am doing now. I have   
   tried brush the bottom side with black ink but the result is not good.   
   Maybe the black tape is similar. But roughening causes me a lot of labor   
   (I do not have sand blast equipment and rub it by hand) :(   
      
      
   --   
   Regards,   
   Lu Wei   
   PGP key ID: 0x92CCE1EA   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)