Nanoslit reflection spectrum



Can anyone tell me if there is anything wrong with my simulation? Why does my reflection spectrum show bizarre oscillations or dips/peaks?

  • Infinite array of nanoslit with period of 800 nm.

polar2_2.fsp (262.4 KB)


Dear @wxlim1

I noticed that you are injecting a Plane Source that is polarized along the y-direction and as a result you are getting a bit complicated pattern. I don’t think there is anything wrong with your simulation as you can see in my convergence testing plot below (results are for different PML layers and simulation area along the z-axis) that they match:

So, I don’t have a clear explanation of the physics, but simulation wise they seem to be reasonable. Also consider that your plot is very wideband, from 500um to 1500um and you might see a lot of dips and peaks!

Moreover, I run simulation for the case that your light is polarized along x direction and I got a better looking result. Please take a look and let me if it makes sense to you.

One reason for why these two simulations are completely different might be because you are using the same periodicity along two axes and if your devices are closer along the width, you might consider adjusting your simulation region.

I hope this could answer your question.


Dear Behzad,

Thank you for helping to check that nothing is wrong with the simulation.
I will see how i can understand this spectrum.