3d far field

quantumopticsquantumoptics Member Posts: 2

Hello ,

I have an structure with 3 slit like the attached file and I am simulating it with 3d FDTD . I want to get the far field with the attached lsf code . but I get the error when I run it . would you please advise me how could that be solved.



  • greg_baethgegreg_baethge Posts: 121Ansys Employee

    Hi @quantumoptics

    Thanks for posting your question on the forum. Ansys employees are not allowed to download any file posted here (see this post), so to be able to help you, could you provide further details on how the simulation is set and the script you are using as well as the error you get. You can post screen copies of the simulation settings, for example.

  • quantumopticsquantumoptics Posts: 3Member

    Thanks for your reply . I try to simulate the 3d model of a 2 slit . and get the far field from that. I want to plot the far. field distribution and my plot axis be wavelength vs angle. I did it in 2d FDTD and could get the result but for 3d I couldnt have it. here is how I simulate the structure and the script would be as follow like the picture. in my script the only change I made is the , I change the farfieldexact2d to 3d. my monitor is 2D monitor z normal .

  • greg_baethgegreg_baethge Posts: 121Ansys Employee

    Thanks for the additional information, @quantumoptics. I think there's a problem in how you define the projection location. The monitor is z normal, and the projection is done at z=112nm, unless the monitor is far from this position (at least 1 wavelength away). the far field calculation might not have much sense. Additionally, you calculate theta from x and y, it should be from x and z.

    In any case, it might be simpler to start from theta, we can calculate the field at a distance of 1m, x,y and z are obtained from theta and we use farfieldexact to get the far field vs x(theta), 0, z(theta). It could be something like:

    theta = linspace(-90, 90, 181);
    thetarad = theta * pi/180;
    x = sin(thetarad) ;
    y =0;
    z = cos(thetarad);
    E = farfieldexact(m, x, y, z, 1:nf, 1.5);
    E2 = sum(abs(E)^2, 2);
    image(theta, lambda*1e6, E2/max(E2), "angle", "lambda (um)");

    I hope this will help!

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