Discussion Forum

Posted: 1 decade ago Aug 19, 2010, 10:18 a.m. EDT

[QUOTE] Dear all, Recently, I have been trying to simulate the SPP generation from single slit under the normal incidence of TM plane wave, a very basic simulation in Plasmoncis, using RF\In-Plane waves\TM waves\Harmonic propagation model. So the calculation area was air in which there was a freestanding metal (gold) film perforated with a single slit, and I set the bottom side as 'scaterring boundary condition', 'magnetic feild' =1A/m to excite the TM plane wave for illumination. The other three sides was surrounded by PML. Of the calculation results, the magnetic field distribution along the upper gold-air interface indicates that the PMLs absorb the propagating SPPs and the diffracted wave by slit well in the upper half space. However, there are some disturb for the field distribution at lower gold-air interface. Maybe, the 'scattering boundary condition' of the bottom side can not absorb the reflected wave by gold film and back-scattering wave by slit very effectively, compared to the upper half space enclosed by PML. Another question: how to excite the perfect plane wave without using the 'periodic condition', since it is the single slit rather than slit array in this model. Could someone give me some suggestions to ameliorate this model or some similar examples? Any help would be very appreciated! He Kaiting [/QUOTE] I guess you can not set a perfet plane wave in total field mode. Maybe you can try with solver for 'scattered filed'. There you do not need to set an excitation port in the boudary condtion inside the simulation domain. In scattered field mode, the excitation is externally and is not influenced by PML. And it is defined in the scalar variable, you define an analytical expression for the perfect plane wave. In scattered field mode, you should notice. Etot=Ein+Esc. you can check in the plot properties, type, Ex-scEx, you should get the Ex distribution of incident field. It should be a perfect plane wave.

Posted: 10 years ago Oct 9, 2014, 3:04 p.m. EDT

I also have the problem to generate a perfect planwave in PML boundary, which means I am using non-periodic calculation. I want to put a air slit in the metal, and to see the scattered light going through the slit. And because the metal layer divide the calculation domain into two parts, it is not suitable to use scatter field calculation since there is no background field on the other side. So in this condition I use Port BC to generate the electric field on one side, and put PML BC on the other 3 edges. But however, I can not generate perfect plane wave when I put everything Air. I know I can put PEC/PMC boundary condition to have a perfect planwave, but the problem is once I put a scatterer in the middle, these boundary doesn't work any more. Can someone tell me how to solve this problem?

Attachments:

• Air_slit_in_metal_1step.mph