Description

Retrieves the intrinsic parameters of the polarization state of a specified ray.  Depending on the number of rays traced, it may be necessary to dimension ray index and ray counter variables as data type Huge_ instead of Long.  Please see Multi-threaded Raytracing for more information.

Syntax

GetPolarization2 id, polar

Parameters

id As Long (or Huge_)

Ray identifier.

polar As T_POLARIZE2

Structure containing the intrinsic polarization state data for the specified ray.

Remarks

This subroutine retrieves the intrinsic parameters of the polarization state for a specific ray in the ray buffer and stores that data in the parameter polar.  If there is a problem, an error is posted and the subroutine returns without modifying polar.

The data returned by GetPolarization2 is at a more fundamental level than the data returned by GetPolarization.

In general, the polarized field is defined as

E = Sqrt(rayflux) × (ap p + as s + ad d) × Exp[i(2p/l)×OPL]

where d is the ray direction and s x p = d,

ap = pAmpReal + i pAmpImag,

as = sAmpReal + i sAmpImag,

s || p  and ad = 0 except in birefringent media.

Example

The following script example calculates the real and imaginary components of the E-field along the S, P, global X and global Y directions using the GetPolarization2 subroutine.

Dim pol2 As T_POLARIZE2

Dim ray As T_RAY

Dim pi As Double

Dim sx As Double, sy As Double, sz As Double

Dim px As Double, py As Double, pz As Double

Dim dx As Double, dy As Double, dz As Double

Dim Esreal As Double, Epreal As Double, Edreal As Double

Dim Esimg As Double, Epimg As Double, Edimg As Double

Dim ExRe As Double, EyRe As Double

Dim ExIm As Double, EyIm As Double

Dim thetas As Double, thetap As Double, theta As Double, mags As Double, magp As Double

Dim iray As Long, cnt As Long

pi=Acos(-1)

ClearOutputWindow

'write header

Print "Ray ID";

Print "EsRe";

Print "EsIm";

Print "EpRe";

Print "EpIm";

Print "ExRe";

Print "ExIm";

Print "EyRe";

Print "EyIm"

'loop over all rays in the buffer

cnt=0

success=GetFirstRay(iray,ray)

While success

          cnt=cnt+1

          'retrieve the d vector, calculate p and the phase

          GetPolarization2 iray,pol2

          sx=pol2.sX : sy=pol2.sY : sz=pol2.sZ

          dx=ray.a : dy=ray.b : dz=ray.c

          CrossProd3D px, py, pz,-sx, -sy, -sz, dx, dy, dz

          theta=2*pi*ray.pathlength/(ray.wavelength*1e-3)

          'magnitides of s and p components

          mags=Sqr(pol2.sAmpReal^2+pol2.sAmpImag^2)

          magp=Sqr(pol2.pAmpReal^2+pol2.pAmpImag^2)

          'relative phase of s and p components

          thetas=Atn2(pol2.sAmpImag,pol2.sAmpReal)

          thetap=Atn2(pol2.pAmpImag,pol2.pAmpReal)

          'real & imaginary components in s and p directions

          Esreal=Sqr(ray.power)*mags*Cos(theta+thetas) : Esimg=Sqr(ray.power)*mags*Sin(theta+thetas)

          Epreal=Sqr(ray.power)*magp*Cos(theta+thetap) : Epimg=Sqr(ray.power)*magp*Sin(theta+thetap)

          'real & imaginary components in the x and y directions

          ExRe = Esreal*pol2.sX + Epreal*px

          EyRe = Esreal*pol2.sY + Epreal*py

          ExIm = Esimg*pol2.sX + Epimg*px

          EyIm = Esimg*pol2.sY + Epimg*py

          'print data to Output Window

          Print iray;

          Print Esreal;

          Print Esimg;

          Print Epreal;

          Print Epimg;

          Print ExRe;

          Print ExIm;

          Print EyRe;

          Print EyIm

          success=GetNextRay(iray,ray)

Wend

See Also

GetRay

T_POLARIZE

T_POLARIZE2

GetPolarization

SetPolarization

SetPolarization2