Learning Forum

[jxx89]

We would like to ask questions about the DGTD solver of Lumerical.

Is it using nodal basis function or vector (edge) basis function?

And when conducting NF2FF transformation, does DGTD solver compute the field info at those near field points, and use the nf2ff function in FDTD solver to construct the farfield information?

Moreoever, based on the official instruction of Lumerical (https://support.lumerical.com/hc/en-us/articles/360034397054-Far-field-projections-in-DGTD-overview) '  Second, the far field projections in DGTD operate on unstructured data rather than rectilinear data '

I don't understand why a spherical surface is used instead of a rectangular box to capture the transient near field data. I am not sure if we would receive a proper response from them?

[Guilin Sun]

While there is no explicit description about Lumerical DGTD, from its reference here Discontinuous Galerkin Time-Domain (DGTD) solver introduction
it seems it uses nodal basis function.
The algorithm for near2far projection is described in the same page. FDTD uses similar method which you may find it from the literature.
Far field at 1meter sphere is to ensure all the projections are at the same distance. Rest assured that you will be able to get proper response for nano photonics simulation.