I’m PhD student and is currently using FDTD to solve for a light absorption problem. The geometry of simulation looks like this: a plane wave (633nm) falls on a gold probe. I used the analysis group Pabs_adv to determine the power absorbed by probe. In the script of Pabs_adv I normalize the power: I multiply by the input intensity and the area of the plane wave source (Input power). Input intensity is 1*e^10 W/m^2, and area of source is 4 um^2. And I have a question - why is absorbed power depends on the distance between the probe and the source, despite the fact that is a plane wave. When I move the plane wave source, I get different values of Pabs.
I have attached the FDTD file with my simulation.
Thanks in advance!