On Tuesday, May 27, 2014 11:29:34 AM UTC-4, Phil Hobbs wrote:   
   > On 05/27/2014 10:47 AM, ggherold@gmail.com wrote:   
   >   
      
   > > OK here's another question.  When I look at the responsivity of   
   photodiodes,   
   > > does that number include the reflectivity of the silicon.   
   > > (something like R = 0.36 for normal incidence... (assuming index of   
   refraction of Si is 4.)   
   > > Do they put some sort of coating on the PD to reduce this?   
   >   
   > >   
   >   
   >   
   >   
   > There are two broad classes of Si PDs, those with QEs of about 0.6   
   > (uncoated) and 0.95 (coated).   
   >   
   > A PD with unit QE has a responsivity of 1.24 A/W * lambda(microns).   
      
   Oh, sure... some combo of c,e and h. (hc/e)  I guess I should just go back to   
   the basics :^)   
   Hey this if great*, so the typical (0.6 A/W near peak) is low because of the   
   reflection... Does anyone put their diodes at Brewster's angle?   
   (peck, peck) ~75 degrees, that's a bit extreme.   
      
   George H.   
   (*I learned something today.)   
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   > Dr Philip C D Hobbs   
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