%pol_wave_demo.m
%1/15/01  TDM
%
%input vector: state = two-element jones vector
%                       first element is the y axis
%                       second element is teh z axis
%                       the propagation direciton is x
%       On the plot, the wave travels to the right as
%          if the axes are assigned to the "convention"
%          of having xy polarization axes and z propagation.
%          I did it this way to simplify the matlab code.
%          The user enters the polarization "state" vector
%          external to this program like the xy convention.
%          That is, state = [1 1] looks like linear along
%          45 degrees in a conventional drawing.

Npts        = 30;
xvec        = linspace(0,1,Npts);
yvec        = zeros(1,Npts);
zvec        = zeros(1,Npts);
uvec        = zeros(1,Npts);

tvec        = 0:0.1:2; 

figure(2);

for t = tvec

vvec        = real(state(1)*exp(2*pi*i*(xvec-t)));
wvec        = real(state(2)*exp(2*pi*i*(xvec-t)));
rho_vec     = (vvec.*vvec + wvec.*wvec).^(0.5);
max_plot    = max(rho_vec);
quiver3(xvec,yvec,zvec,uvec,vvec/max_plot,wvec/max_plot,0,'.','filled');
view([30 30])
axis([0 1 -1 1 -1 1])
pause(1)

end