Learning Forum

[Sangmyeong Yu]

I conducted a simulation and observed unnatural spectra at certain points. Could this phenomenon be attributed to nonlinear optics, or should it be considered a simulation error? There were no error messages after the simulation concluded. I specified the mesh, and the boundary conditions (BC) for the xy axis are periodic. The source used is a plane wave.

[Afroditi Petropoulou]

Dear Sangmyeong,

What are the materials that you are using for the two objects and what are their dimensions (of the rectangular, cylinder and FDTD region)?

As I can see you run a sweep over the period, is that correct? Is it for both x and y axis span?

Did you check the material fitting in the material explorer to see if it is ok for the whole bandwidth (300nm-1000nm)?

Thank you in advance.

Best Regards,

Afroditi

[Sangmyeong Yu]

Here, my sweep setting and material fittings(300nm~1000nm and 380 nm 780 nm Ag), and I used Ag(cylinder), Si3N4(cylinder), SiO2(rectangular).

Si3N4, SiO2 material fitting is perfect but Ag is not correct.

I believe I have done my best in material fitting. Also, I used the Ag (Silver) provided in FDTD.

[Afroditi Petropoulou]

Dear Sangmyeong,

The first fitting (first image that you shared) looks fine.

I have a question though for the sweeps. Is the second sweep inside the first one?

If yes, I see that the radius is up to 0.13um will the period (y and x FDTD span) is down to 0.2um. Is this intentional? Because for 0.2um span and 0.13um radius the cylinder will be larger than the simulation area in x and y axis. This might give weird results. Since you have periodic boundary conditions, in this case the cylinders will overlap.

Best Regards,

Afroditi