Discussion Forum

Can you help me in this regard?
I would like to find the electric filed intensity of reflection(or reflectance) from gold nano pillars from gold substrate, with the consideration of diffraction orders in case of reflection((1,1 ), (1,0 )reflection grating orders), for the different wave lengths starting from 200 nm to 1000 nm, for a fixed angle of incidence (normal incidence, or 30 degree angle of incidence)

I had made a 2D grating structures in 3D modeling Wizard of Comsol 4.4 version, While I am putting Diffraction orders( m=0, n=0 ; m=-1, n=0 ; m=+1, n=0) with "port reference points" as diagonally opposite end of Unit square cell with periodic boundary conditions on all four sides( by doing copay face). Unfortunately it gives me zero electric filed while i am running., If I run the same model without diffraction order it gives the result but only from one order diffraction (normal reflection) . Since I need to calculate reflection from at least two orders (0 th order and 1 st order) I have to include those diffraction orders to my model

Can you help me in this regard?
can you tell me how to put diffraction orders (with proper port reference points)in 2d grating on 3D model?

Also How can i implement PML layer over the port ( or it is really needed ), since if i add PMLl layer on the top of port, selecting port reference point is declined by default. I follow the pyramidal absorption model for making the infinite array of my 2d Grating nano structures( there a PML layer added over the port)

the plasmonic wire grating model available in Comsol library is just a 2D model , so we can't able to follow the same thing in here in our model.

I used this blog for making port reference points and putting periodic ports
www.comsol.co.in/blogs/modeling-electromagnetic-waves-periodic-structures/

Here I am attaching the COMSOL model named as 2port_modified_Au_nanocylinder.mph , please go through this model ( it do not giving expected result)

Also another pdf attachment in which the model ( result by FDTD) which i am trying to reproduce it by COMSOL FEM also attached with this mail.

In this paper figure-2 (a) is the graph which i am trying to reproduce it. also in the , figure 2.b is they component magnetic filed intensity in y-z cross section for separate modes, figure 4 is the electric filed intensity which is corresponding (1,0) grating order ((1,0))plasmonics mode) for peak

Please help me in this regard..
Thank you


Aneesh M Joseph
Indian Institute of Science, IISC
Banaglore