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Scattering / extinction / absorption cross-sections of silver nanowires (infinite cylinders) using meep

Particles scatter and absorb electromagnetic radiation. One often needs to compare the amount of scattering/absorption/extinction for particles of different shapes, composition, sizes and incident light properties (polarization, frequency and angle). In this regard, the concept of cross-sections comes into picture. There are three types of cross-sections, 1) scattering 2) absorption and 3) extinction. All of them have units of area, $m^2$, and provide a measure to quantify scattering/absorption process. Here using MEEP I calculate the crossections of silver nanowires and compare them with numerical solution (code from Bohren and Hauffman book).

Comparison of meep results with analytical results for silver nanowires

 

To achieve this, I wrote a meep code that performs a 2D simulation (x-y) with the cylinder axis along z axis with sources and monitors places as shown below. The source is a line source which travels along y direction and has polarization with electric field along x axis (along radius). I also use mirror-symmetries anti-symetry along X direction (which reduces the simulation time by half). PML layers are used on all sides. Calculation of cross-sections involves creating multiple 1-d flux monitors and running multiple simulations as shown below.

Here is my project file.. You would need ubuntu like system with meep and octave installed. Shell script will do all the work.

I have also shared the project at github.

arrow9 Responses

  1. 64 mos ago

    Hi,

    Did you use Drude-Lorentz model for silver? What is the amount of a used in this model? I found that the output results are very sensitive to a.

    Best,

    Khai

  2. Bala Krishna Juluri
    64 mos ago

    Hi Khai,

    Yes. I used Drude-Lorentz model for silver as described at http://juluribk.com/2011/04/27/plasmonic-materials-in-meep/

    I choose a of 100 nm, you can find the meep code for the material definition at the same link.

    Good luck!
    Bala

  3. Wu
    57 mos, 1 wk ago

    Hi Bala,

    I’m a new learner of MEEP. Could you show me the code of calculating the scattering cross section in meep. .I really want to know how to do it.

    My email address is?wtf2004@yahoo.cn

    Thank you very much!

    Wu

  4. Luis
    56 mos, 4 wks ago

    Hi Bala,

    It’s been a good long time since you promised to post how to compute the cross sections. At this moment, It would be of enormous help if you did :)

  5. Wu Tengfei
    56 mos, 4 wks ago

    Dear Bala,

    I’m a new user of MEEP. I saw the article “Scattering / extinction / absorption cross-sections of silver nanowires (infinite cylinders) using meep ” on your website.

    I have read many discussions on the group “gmane.comp.science.electromagnetism.meep.general “. However, I’m still puzzled on how to calculate the scattering/absorbance/extinction cross section.

    Could you tell me how to do this or show me an example which will be the best? I’m expecting your reply.

    Best regards,
    Wu

  6. Zhang Pengfei
    50 mos ago

    Dear Bala,

    Could you kindly give me the meep code of calculating the scattering cross section? zpf029@gmail.com

    Thank you very much!

    Best Regards,
    Zhang

  7. Bala Krishna Juluri
    49 mos ago

    Now you can download the project file. Click at the link in the post.

  8. Tapsanit
    48 mos, 1 wk ago

    Is the the variable “rad” referred to the radius of the infinite wire?

  9. Bala Krishna Juluri
    45 mos, 3 wks ago

    yes. it refers to the radius.

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