Simulation of optical frequency region with CST MWS

[inter99]

cst optical frequency

I want to simulation of optical near field enhancement with CST MWS.

Optical near field enhancement is the problem of optical frequency(hunderd Thz),
and 10~100 nm size metal particle.

So my simulation condition is so simple.

1. Make 100 nm sheroid with metalic.
2. Excite plane wave of linear polarization.
3. All boundary is open or open(Add space)
4. E-field monitoring with specific frequency(About 375 Thz)
5. Transient solver.
5. All mesh value default 10.(line per wavelength, ratio, limit.etc)

My critical problem is about meshing. The results are varying with mesh size.
Of course, too low mesh density make error. But, When incearing the mesh,
solution is divergent.(Very high E-field at the end of boundary..,I can't see)

So, I want to know about specific standard about meshing
1. Line per wavelength
2. Lower mesh limit
and the other settings.

Have anyone experience about this?

 

[adel_48]

Hi,

Actually for such simple problems (I mean geometrically simple ) the default mesh properties should be fine.

May be your problem when you changed the mesh size was that the solution became unstable in certain regions ?

You can try to disable the PBA mesh (go to Mesh\Global Mesh properties the press "specials" and select staircase mesh in the window that appears) this sometimes overcomes the instability problem but you will have to increase the number of lines per wavelength a little bit.

Another one to remove this stability problem is to adjust the solver stability factor (Solve\Transient Solver then press "Specials" and in the "solver" tab you will find stability factor (the default is 1) but you may reduce it to improve stability (make it 0.5 or 0.2 but not too low since your simulation time will change by the inverse of this number

Hope this will help,
Adel

 

[khang2007]

Hi, i have tried to simulate a nanoantennas made with 2 nano-rod and fed at the gap center as I want to get the input impedance of such nano dipole.
However, the energy decayed very strange, many ripples, and I could not re-produce the results as the paper showed.
It seems simple, but ...
Who could give me a hand?

Article "Input impedance, Nanocircuit loading, and radiation tuning of optical nanoantennas"

Thanks in advance!