## Photonics

Topics related to Lumerical and more

#### how to calculate transmission of a particular polarized tranmission

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• xiaofei.xiao15
Subscriber
• Guilin Sun
Ansys Employee

For linear polarization, you can do two seperate simulations with x and y polarized source (z propagation), calculate polarized transmission by integrating the individual Poynting vector; or you use a 45 deg polarized light. for example,

PoyntingV=Ex*conj(Hy)-Ey*conj(Hx) is the total

PoyntingV_X=Ex*coj(Hy)  X-polarized

PoyntingV_Y=-Ey*conj(Hx);  Y polarized

then you integrate them: integrate - Script command

Do not forget 0.5 and use the real part:https://optics.ansys.com/hc/en-us/articles/360034405354-transmission-Script-commandhttps://optics.ansys.com/hc/en-us/articles/360034405354-transmission-Script-command

and normalize with sourcepower:https://optics.ansys.com/hc/en-us/search?utf8=%E2%9C%93&query=sourcepower

For circular polarization, you have to decompose the monitor data from Ex,Ey, Hx and Hy into EL,ER, and HL, HR, and then do the same thing.

Please note that this is based on the assumption that the near field does not have higher order diffraction. In case it has, you will need to use grating analysis (supose it is periodic, or "s param“ analysis group otherwise) to get the farfield Ep, Es, and then calculate their power. In this case you can get the power from the optical intensity: https://forum.ansys.com/forums/topic/ansys-insight-guangxueqiangdugongludianchangqiangdupingfangdeguanxiyijidiancinengliang/

Since it is plane wave (at least in the farfield), directly use abs(E)^2 is ok. However if it is angled, you may need to correct the cosine factor.

Please find some reference papers for the decomposition.