Repository: NanoComp/meep

Issue #1442: Request for non-uniform grid 
Created: 2020-12-02T15:45:46Z
Dear meep developers,
I have recently started using meep and I have to say I am very happy with the efficiency of the simulations and with the accuracy of the results that it provides. There is only one certain feature that I and some of my colleagues feel would be extremely useful but is currently missing from meep. This missing feature is the ability to define  a non-uniform grid (something that has also been discussed in the support page in the past).
There are several reasons why we believe the addition of a non-uniform grid would be valuable to meep users.


The simulation speed and computational demands could be significantly reduced depending on the geometry of the simulation.


This could allow performing simulations that include structures of very different sizes.


Plasmonics simulations would significantly benefit from this addition. Given that plasmonics have become extremely popular over the past decade this could prove to be very useful for a lot of users in the field.


Simulations of 2D materials (especially in combination with 3D materials) would also benefit from such an addition. Even more so since 2D materials  (especially the ones with in plane anisotropy) can have very interesting optical properties in the infrared range, something that further increases computational demands since both high resolution and large simulation regions are required.


Simulations including nonlinear materials (for example in the form of waveguides) and plasmonic resonators that can be used to induce/enhance/or manipulate the nonlinear response of the system would be possible in meep with lower computational demands. Same when studying the nonlinear properties of plasmonic nanostructures themselves.


In the past I have used commercial FDTD solvers that include a non-uniform grid, and graphene or even black-phosphorus plasmonic nanoresonators could be efficiently simulated quickly and without requiring an extremely powerful pc. Thus i believe meep would also benefit a lot from this addition. I understand that many of these simulations could possibly be performed with an FEM solver, but I am not sure there is an available open source or free solution that is as flexible as or as efficient/trustworthy as meep (including dispersive, anisotropic, nonlinear materials etc).
Regardless if this feature is planned to be included in the future, I would like to thank you for providing this amazing simulation tool and excellent documentation for free and also for the useful advice you provide to the users in the support page. I would gladly donate to support this software if there is an available donation page.
Best wishes
Nikolaos Matthaiakakis

Duplicate issue #2606: multiple grids support?
Created: 2023-08-14T13:44:02Z
Will meep in the future has a roadmap to include multiple mesh grids as Lumerical do?
The beneficial is that it can greatly reduce the computational time when only fine precision of meshes are applied within high refractive material and boundaries.

Closing comment (2023-08-15T14:58:29Z): Duplicate of #1442.   It's something we've thought about, but no one is working on it at the moment