 ## Photonics

• ejlee0911
Subscriber

Hello.

I have a question about calculating the transmittance of circularly polarized light.

I use the LCP for source with Fabry Perot cavity optimized for circularly polarized light.

The Fabry Perot cavity I use may show different results for LCP and RCP.

So I have to check the transmittance and reflectance of each circular polarization.

To find out the optical properties, I use the script below referring to https://forum.ansys.com/forums/topic/YuanPianZhenGuangQiuZhuanHuanXiaoLu/.

I want to know if the script is right.

###### ##################################################

f=getdata("R","f");

lamda=c/f;

x=getdata("R","x");

y=getdata("R","y");

R_Ex=getdata("R","Ex");

R_Ey=getdata("R","Ey");

R_T=getresult("R","T");

##########################################

Ex0 = pinch(R_Ex(find(x,0),find(y,0),1,:));

Ey0 = pinch(R_Ey(find(x,0),find(y,0),1,:));

R_data = R_T.T;

RCP_R2 = (Ex0+1i*Ey0)/sqrt(2);

LCP_R2 = (Ex0-1i*Ey0)/sqrt(2);

prop_RCP_R2 = abs(RCP_R2)^2;# total energy of RCP component of T

prop_LCP_R2 = abs(LCP_R2)^2;# total energy of LCP component of T

R_R = R_data*prop_RT_R2;

R_L = R_data*prop_LT_R2;

plot(c/f,prop_RT_R2, prop_LT_R2, "lambda","Re_RCP", "Re_LCP");

RCP_R2 is the EM equation. I guess, "prop RCP_R2" is the power of the reflectance of RCP.

The definition of reflectance and transmittance is power/power, so is it need for 'prop RCP_R2' to divide by the total power of the source to figure out the reflectance or transmittance?

In the reference post, the writer used the script function 'TotalEnergy' in the second picture.

• Greg Baethge
Ansys Employee

Hi ejlee0911,

Thank you for posting your question on our forum. I think the overall idea of reconstructing the LCP and RCP response is going in the right direction, but the script only takes the E field components at the center of the monitor. I think a more generic approach is possible using S parameter calculations, as discussed here.

The idea is similar, we calculate the s and p components of the S parameters, and reconstruct the LCP and RCP to get the conversion efficiency.

I hope this will help.

• ejlee0911
Subscriber

Thanks for your help!

I have a question to use S parameter.

A generic approach you kindly mentioned is applied for metasurfaces in which the incident light was coming outside from them.

But I would like to check the results when the source is inside the structure. And is it still okay to define the metamaterial span and center? 