Learning Forum

[ejlee0911]

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 /forum/forums/topic/YuanPianZhenGuangQiuZhuanHuanXiaoLu/.

I want to know if the script is right. 

 

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

# Total energy of LCP component of monitors (R and T)

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

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]

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]

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? 

 

 

 

[Greg Baethge]

Hi ejlee0911,

Our apologies, it seems we missed your question here! As you mentioned, the approach we used is meant for metamaterial used in transmission or in reflection. The span and center are used to compensate the phase accumulated by the light travelling from the source to the metamaterial and then to the monitors used for the calculation.

I think we need to keep this compensation even if the source is within the metamaterial. Since we use the position of the source and monitors, the calculation should still work, but I would suggest to check it.