Analysis of seemingly identical simulation regions using same script yields different absorption/spectra results


#1

Hello,

I have been modifying the mie3d sample files provided here on Lumerical’s website in order to simulate a single nanoparticle on a silicon substrate. I have also modified the provided analysis script to accommodate for structure names. When I run the analysis script, I obtain the following cross sectional results:

Next, I decided to build an identical simulation region myself in the structures tab and run the same analysis script. Curiously, I obtained different results:

From what I can tell, everything defined in the simulation region I created is identical to the first. However, there clearly is something that I did not account for. Could someone perhaps help me look through my simulation files to see what I may have overlooked?

Thanks in advance.

mie_analysis_3d_ga.lsf (6.8 KB)
mie_ga_3d_modified.fsp (342.4 KB)
user_generated_simulation.fsp (361.8 KB)


Differences between simulation results and mie3d function
#2

Dear @eelu

It looks like you TFSF injection axis is different in these two simulations. Once I set the injection angle to be z-axis forward in mie_ga_3d_modified.fsp, results were identical.

Additional note:
Please note that you can not inject TFSF source in the y-axis. This is because the TFSF is parallel to substrates. The correct usage of TFSF is explained in detail in this link (see orientation with respect to the structure section):

https://kb.lumerical.com/en/index.html?ref_sim_obj_tfsf_sources_usage.html

I hope this was helpful.