Photonics

Photonics

Topics related to Lumerical and more.

FarField calculation and understanding

    • tropshm
      Subscriber

      Hello, I'm trying to use FarField in Lumerical, I have the beam shape of single emmiter and than I upload it to new FDTD simulation as source and I build 10 on 10 sources with it to simulate far field of phase array. after I calculate the nearfield with detector I use Farfield calculation to determine the farfield picture the array will give me. now the plot is polar one and when I take the data (or plot in new windows) its become only in ux and uy axis. But what I need is to determine the width of the beam in the real world and I'm not sure how to use ux,uy to transform it to real width of the beam I tried script that there is in the examples but when the beam was in direct (no phase change in the array) the resaults were infinite width in the phi axis.

      I would like to some help firstly to understand if my method is curect and how to extract real information from the data given to me

       

      Tnx

    • anna.wirth-singh
      Ansys Employee

      Hello, 

      The far field results are a function of angle, and the ux, uy units can be converted to spherical coordinates using the farfieldspherical command. More information about these units is here: Understanding direction unit vector coordinates in far field projections – Ansys Optics

      However, I think that what you may need instead is the farfieldexact script command: farfieldexact3d - Script command – Ansys Optics

      This script command will calculate the fields on a specific plane in space with Cartesian coordinates x, y, z. So rather than convert the angular far field results to another coordinate system, it may be more straightforward to calculate the exact fields using farfieldexact3d. Will this help you to obtain the information you need?

      Best,

      Anna

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