The Mie scattering example can also be simulated using the Finite Difference Time Domain solver
available in Lumerical’s FDTD Solutions.
The simulation settings are quite similar to the DGTD simulation.
However, as the FDTD solver uses a rectilinear mesh, it can be challenging to resolve non-planar
material interfaces such as the sphere we consider in this example.
On the other hand, as DGTD uses an unstructured mesh, it is better at resolving such geometries.
In addition, DGTD’s capability to resolve discontinuous fields at metal/dielectric interfaces
can be critical when studying structures involving metal interfaces and plasmonic effects.
As a proof of concept, we performed a convergence study on the Mie scattering example using
both DGTD and FDTD solvers.
In this plot, the level of accuracy obtained and the corresponding simulation time is compared
for both optical solvers.
As expected, for a more refined mesh, the simulation takes longer and the error becomes
For lower accuracy simulations, FDTD will be faster, up to a certain point.
Beyond that point, DGTD can reach the same level of accuracy as FDTD in a much shorter
time and this difference in simulation times becomes even larger for higher accuracy simulations.
This demonstrates the advantage of DGTD over FDTD as an optical solver for certain applications.
In the next section, we will learn some simulation tips on how to perform efficient and accurate