I am trying to extract the charge density as a function of time. The divergence current analysis group
calculates the spectrum of the charge density - it uses the E(w) in the script, calculated
by the frequency-domain monitor.
Therefore, I try to do the inverse transform in matlab, but I am facing a problem:
The frequencies I chose to simulate are in the visible range (3.75-7.5e14 rad/s) and the resulting spectrum
is in that range. So if I use ifft function should I get the physical signal as a function of time, or should I include lower frequencies in my simulation as well? Does Lumerical simulate in all frequencies and provide me only the frequencies I asked for?