Thank you very much for providing the concept.
I am attaching a previous report but they used different software but not OPTIFDTD.
They have used the same configuration (i.e light is incident perpendicular to the NW axis) but with PBCs.
we are interested to find the transmittance and reflectance spectra of the same configuration but with PMLs.
I have just taken this 60nm half-width from an example.