Guilin Sun
Ansys Employee

A1: you are right that,using periodic BCs will force the dipole to duplicate, which might not be what you want.

You can use PML, provided that the simulation region is large enough that you can see the contributions from the periodicity. You can use monitors inside the periodic structure and make sure the fields at the edges are very small.

A2: Please note that there are two definitions of the Purcell factors and they do not necessarily give the same result. The Purcell factor calculated inside the dipole is dipowerpower/sourcepower, where the sourcepower is calculated assuming the dipole is in that homogeneous material.

In addition, the dipolepower can diverge if the mesh is very small. However we do not know exactly how small it can be before diverging: dipolepower - Script command

Greens function and local density of states of a dipole source

A3: the two methods may not lead to the same result. Maybe you can choose one of the two. It is good to know that the dipolepower gives the same as the box method.  You mat test if the online exmples give the same results with the two methods.