Learning Forum

[StandAloneComplex]

Hello,

I am trying to obtain reflection spectrum for random distributed nanostructures on a Si substrate. I am referring your "Scattering of PSL and Cu spherical particles on a substrate". Before simulate with nanoparticles, I did simulation to check reflection spectrum of Si substrate is correct.

However, the reflection monitor placed within scattering region does not look same as Si reflection spectrum found in literature. One thing I noticed is that the reflection monitor placed within total field region has similar shape with Si reflection spectrum. Could you please share with me how to obtain reflection spectrum in this case.

Simulation condition is listed as below;

PSL_Cu_scattering.fsp was downloaded. Some parameters are changed including:

1. In TF/SF source: phase, theta, phi, angle->0
2. Frequency: 200-1500 nm. (global monitor frequency points 50)
3. sphere was disabled
4. Another DFTMonitor was added in totalfield "R_totalfield"

Any helps are greatly appreciated. Thank you!

[Guilin Sun]

to obtain reflection spectrum for random distributed nanostructures, I would suggest that you refer this example: Bidirectional scattering distribution function (BSDF)
"the reflection monitor placed within scattering region does not look same as Si reflection spectrum found in literature" when you place monitor in the scattering region, you get scattering result. When you have a flat surface, ideally the scattering is zero. However due to numerical error it has very small scattering, due to non-uniform mesh and source injection errors. In particular, this example uses local override mesh, which makes the plane wave distorted, which will create "scattering".
Please refer: Tips and best practices when using the FDTD TFSF source
and Understanding source normalization in the TFSF source
or you can find some reference papers.
We do not expect to get the same result in the scattering-field region and total-field region, as the scattering field is the difference of the incident and transmitted