I was trying to simulate a Photonic crystal defect in COMSOL. My model is a square array of dielectric cylinders in air matrix with a point defect at the center. I want to calculate the Q-factor and the mode volume of the defect. I can calculate the Q- factor from the reflection spectra using FWHM and the center frequency of the defect mode and also from the eigenvalue analysis applying scattering boundary conditions. But I’m getting different values for the same model.
Is there any way to calculate the mode volume directly from the model? I have tried by defining it in the variables. But I’m not sure about how to specify the position-dependent electric field intensity and dielectric permittivity etc.
Note: I’m attaching the equation for effective mode volume.
[https://drive.google.com/open?id=1sjek99_Oetp8aMkMUofjEpvp8Snx0Mu5](http://)