I used COMSOL for plasmonic simulation in Krestchman structure.

The excitation of SPP in specific angle can be seen.

Comsol calculates a parameter emw.k, which is actually sqrt(kx^2+ky^2).

For dispersion curve I need just ky.

I do not know how to extract ky from emw.k.

I am thinking of pointing vector which shows the direction of propagation in order to find the angle of emw.k and ky, but the desired result is not achieved.