phase of circular polarization light
I'm calculating the phase and conversion efficiency of circular polarization light in a metasurface structure.
Before designing my own structure, I'm trying to reproduce the reported results of "Broadband achromatic metalens in the midinfrared range".
I can get same result of the conversion efficiency as shown In Fig 2. However, the calculated phase value is quite different compared with the paper's result.
How can I calculate the phase delay of LCP or RCP induced by metasurfaces?
I attached my source code, FDTD file, and the paper.