Hi
thank you for your answer.
I am still playing with the grating structure and analyzing the possibility to change the refractive index of the structure named silicon in the tutorial https://optiwave.com/optifdtd-manuals/fdtd-transmission-and-reflection-spectrum-from-grating-unit-cell/.
My model does not work, even if I have included the properties of the silver.
Could you please check it?
thank you.