Learning Forum

[xihangshi]

I am using Lumerical Finite Difference IDE. I put a dipole at 1um above a dielectric, and then put a line monitor pass through the dipole.   I want to record the scattering field at the line monitor. How could I do that

The line monitor cannot distinguish the field from the dipole and the field scattered by the dielectric. I thought run another simulation with the dipole in a vacuum only as the background. However, the subtraction at the dipole point gives the wrong result. 

Is there other way to distinguish the scattering field by the dipole at the dipole point?

 

 

[Dimitris Polyzos]

Hello Xihangshi,

I am not sure if the setup of your model is correct. The dipole source travels in parallel with the dielectric and the scattering needs a small particle or structure to happen. Correct me if I am wrong but I cannot see any small structure in your model. A little bit more information would be useful, or the reference of your model.

Howver, some useful information how to set your dipole source correclty can be found in the following links:

Dipole Source in Ansys Lumerical FDTD – Lesson 6, Part 1

Dipole Source in Ansys Lumerical FDTD – Lesson 6, Part 2

Dipole-source-Simulation-object

Some application examples where you can pump some ideas how to setup your simulation can be found below:

Bandstructure-of-photonic-crystal-with-loss

Scattering-list-of-examples

I hope I helped. Let me know if you need further help with your model.

Kind regards

Dimitris

[xihangshi]

Thanks Dimitris. 

The dielectric should scatter the dipole field. The point dipole at the red point in a vacuum, above the dielectric. Meanwhile, I put a line monitor in the vacuum too, parallel to the dielectric surface, and pass through the dipole point.  Now the monitor can only record the total field, but I want the scattering field. 

[Dimitris Polyzos]

Hello, 

I would recommend to check the far field of the reflection from the dielectric as I think that the near field for both monitors might be very similar to each other. First check the field that is above the dielectric and then the field of the monitor at the background. Please refer to the following links for farfield calculations  and applciation examples

Polar plot of scattered field with particle on substrate

Far field directivity calculations of an antenna

Lumerical scripting language - Alphabetical list

I hope I helped. Please do not hesitate to come in contact for any query you might have.

Kind regards

Dimitris