Dependence of farfield from monitor position

gabcavicchiogabcavicchio Member Posts: 3
edited April 29 in Photonics

Hi,

I've been simulating a grating coupler in Lumerical FDTD and I'm interested in the farfield diagram of the field irradiated by the grating. To realize one, I put a DFT monitor at the top of the grating that collects all the light emitted and then I use it to plot the farfield. However I noticed, that my farfield diagram is really sensitive to the distance of the monitor from the grating.

Do you have any tips or suggestion where to place a monitor correctly for this kind of work?

Thanks in advance

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Best Answer

  • kjohnsonkjohnson Posts: 91Ansys Employee
    Accepted Answer

    Hi @gabcavicchio ,

    Generally, when using a DFT monitor for far field projections it is best to place the monitor as close as possible to the scattering object, with as large a span as possible. This allows the monitor to record the light propagating at as wide a range of angles as possible. It might be useful to expand the span of your simulation region as well, if this means you can make the monitor larger.

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