Learning Forum

[teddie smith]

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?

[Guilin Sun]

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.

 

[teddie smith]

They used a normal incident light with a plane wave.

Anyway, I solved the problem. Thank you.!