Learning Forum

[ph23resch01002]

In the Parameter sweep, I rotate the meta atom to get the phase shift and its transmission coefficients for the RCP incident light using a transmission monitor. (Two sources where the polarization angle of 1 source is set to 0 degrees and the other is set to 90 degrees and the phase shift between the two sources is -90 degrees). The light is incident on the meta atom from the air side, not the substrate side)  I get one set of Transmission coefficients using this approach. I used another approach to calculate the same. I did the parameter sweep for different theta values, for x polarised light and y polarised light as well, and then using the s parameter analysis I calculated the phase shift and the transmission coefficients for both RCP and LCP incidence. I will attach the code in the attachment. The result that is get is different. I am basically doing the same thing using the different approaches. Then what is the reason for the discrepancy? Can anyone please clarify my doubt?

I also have another basic doubt( Silly doubt ), when we are calculating the Transmission coefficients from the s parameter, should we do the abs or absolute squared?

[Guilin Sun]

I guess the "theta"  is the atom rotation angle?

Maybe 

When adding a phase to a complex number, it might not work as expected by simplying multiply 1i to the complext number. This is because complex num ber can only pick up phase between -pi to pi.  I suggest that you use ans(s)*exp(1i*angle(s)+1i*pi/2) . Sometimes it can avoid some issues.

In addition, definitions for left- and right- handed circular polarization can be confusing. Please compare the other handedness and see if it agrees.

You do not need to sweep all the points. Simply sweep just one points and compare the results.   I assume you are accessing S result from the s-param analysis group, and using the grating analysis. If you use the near field data, please make sure there is no higher order diffraction. It is single wavelength source.

Without detailed settings, I can only provide the above suggestions.