Caculation of diffraction efficiency

[Mengyun-0105]

Hi, I recently try to simulation a 1D binary grating stucture refering the notebook here https://www.flexcompute.com/tidy3d/examples/notebooks/GratingEfficiency/

But there was obvious mismatch in diffraction efficiency of different orders vs my simulations in Lumerical FDTD, I wonder if this is because of mistakes in setting, e.g. boundary conditions, mesh, monitors, etc. Please would you be able to provide some help on this.

Happy to share the code if useful. Thanks!