attenuation diagram

Hi every one

I am building a photonic crystal structure on CST and the final result needs to be a band diagram. Once you get the band diagram, I was wondering does any one know how to convert the band diagram (dispersion diagram) to an attenuation diagram (transmission diagram or absorption diagram)? I know that by simulating the same structure on CST using eigenmode solver and frequency solver you can get the band diagram and attenuation diagram but I would like to convert one diagram to another and vice versa without performing multiple simulations.

My main objective is to learn how they are being converted from one form to another. If you are aware of any journal, application or any thing that can help me would be greatly appreaciated.

Thank you in advance

It is not really possible to "convert" a band diagram into a transmission/reflection diagram. The band diagram assumed your photonic crystal was infinitely periodic. A transmission/reflection diagram typically assumes infinitely periodic in x and y, but z is finite with some number of unit cells stacked to form a slab.

With that said, you can "estimate" the transmission spectrum through the density of states. Think of summing all the bands for a given frequency and making the number of bands the measure of transmission. It is crude, but surprisingly accurate. The reflection is then R = 1 - T.

-Tip