Diffraction angle (-90~90 degree)

- February 28, 2023 at 4:25 am
  
  teddie smith
  Subscriber
  
  I want to get a reflection data according to viewing angle.
  Then I know that I need to use grating function because my structure is infinitely periodic.
  But when I found an example about diffraction grating from FDTD, there were only discrete point.
  I want to draw a continuous graph. I uploaded some reference graph.
  
  So, how can I get a data from -90 (or -89) to 90(or 90) degree to this graph?
- February 28, 2023 at 5:19 pm
  
  Guilin Sun
  Ansys Employee
  
  As you know, infinite period grating creates diffraction at isolated diffraction angles. So your result is correct.
  As for the published result, please check the paper again. I suspect that its incidence is a cone beam, such as from a microscope objective. because of broad incident angles, it may induce continuous angular distribution. From your grating analysis, the 1st diffraction has diffraciton angle of 30deg. therefore, I guess the incident beam would have about 30 deg cone. Please check.
- March 2, 2023 at 5:56 am
  
  teddie smith
  Subscriber
  
  They used a normal incident light with a plane wave.
  Anyway, I solved the problem. Thank you.!