%%
%% This Filename:  polstate.mp   [MetaPost source]
%% Creation time:  Wed Apr 19 22:18:57 2000
%%
%% Copyright (C) 1997-98, Fredrik Jonsson <fredrik@physics.kth.se>
%%

path ppa, ppb, ppc, ppd, ppe, ppf, ppg, pph;

%%
%% Coordinate system for LCP
%%
ahangle  := 30;
ahlength := 5pt;
drawarrow (3.3cm,3cm)--(4.9cm,3cm);
label.top(btex $x$ etex, (4.9cm,3cm));
drawarrow (4cm,2.3cm)--(4cm,3.9cm);
label.rt(btex $y$ etex, (4cm,3.9cm));
label.top(btex $({\rm LCP})$ etex, (5.1cm,3.8cm));

%%
%% Coordinate system for RCP
%%
ahangle  := 30;
ahlength := 5pt;
drawarrow (3.3cm,-3cm)--(4.9cm,-3cm);
label.top(btex $x$ etex, (4.9cm,-3cm));
drawarrow (4cm,-3.7cm)--(4cm,-2.1cm);
label.rt(btex $y$ etex, (4cm,-2.1cm));
label.top(btex $({\rm RCP})$ etex, (5.1cm,-2.2cm));

%%
%% Coordinate system for linearly polarized light, with
%% polarization ellipse oriented 45 degrees to the x-axis
%%
ahangle  := 30;
ahlength := 5pt;
drawarrow (3.3cm,0cm)--(4.9cm,0cm);
label.top(btex $x$ etex, (4.9cm,0cm));
drawarrow (4cm,-0.7cm)--(4cm,0.9cm);
label.rt(btex $y$ etex, (4cm,0.9cm));
label.top(btex $({\rm lin.\,pol.})$ etex, (5.1cm,0.8cm));

%%
%% Coordinate system for linearly polarized light, with
%% polarization ellipse oriented along the x-axis
%%
ahangle  := 30;
ahlength := 5pt;
drawarrow (3.3cm-9cm,0cm)--(4.9cm-9cm,0cm);
label.top(btex $x$ etex, (4.9cm-9cm,0cm));
drawarrow (4cm-9cm,-0.7cm)--(4cm-9cm,0.9cm);
label.rt(btex $y$ etex, (4cm-9cm,0.9cm));
label.top(btex $({\rm lin.\,pol.})$ etex, (-6cm,0.8cm));

%%
%% Coordinate system for elliptically polarized light, with
%% polarization ellipse oriented along the x-axis
%%
ahangle  := 30;
ahlength := 5pt;
drawarrow (-5.7cm,3cm)--(4.9cm-9cm,3cm);
label.top(btex $x$ etex, (4.9cm-9cm,3cm));
drawarrow (-5cm,2.3cm)--(4cm-9cm,3.9cm);
label.rt(btex $y$ etex, (4cm-9cm,3.9cm));
label.top(btex $({\rm ellip.\,pol.})$ etex, (-6cm,3.8cm));

%%
%% Coordinate system for elliptically polarized light, with
%% polarization ellipse oriented 45 degrees to the x-axis
%%
ahangle  := 30;
ahlength := 5pt;
drawarrow (-5.7cm,-3cm)--(4.9cm-9cm,-3cm);
label.top(btex $x$ etex, (4.9cm-9cm,-3cm));
drawarrow (-5cm,2.3cm-6cm)--(4cm-9cm,-2.1cm);
label.rt(btex $y$ etex, (4cm-9cm,3.9cm-6cm));
label.top(btex $({\rm ellip.\,pol.})$ etex, (-6cm,3.8cm-6cm));

pickup pencircle scaled 1.2pt;
ahangle  := 45;
ahlength := 3pt;
%%
%% Direction of rotation for LCP
%%
ppa = halfcircle scaled 1cm rotated -45 shifted (4cm,3cm);
draw ppa;
ppb = halfcircle scaled 1cm rotated 45 shifted (4cm,3cm);
drawarrow ppb;
%%
%% Direction of rotation for RCP
%%
ppc = halfcircle scaled 1cm rotated -45 xscaled -1 shifted (4cm,-3cm);
draw ppc;
ppd = halfcircle scaled 1cm rotated 45 xscaled -1 shifted (4cm,-3cm);
drawarrow ppd;
%%
%% Direction of rotation for elliptically polarized light
%% with main axis along the x-axis
%%
ppe = halfcircle scaled 1cm rotated -60 yscaled 0.5 shifted (-5cm,3cm);
draw ppe;
ppf = halfcircle scaled 1cm rotated 60 yscaled 0.5 shifted (-5cm,3cm);
drawarrow ppf;
%%
%% Direction of rotation for elliptically polarized light
%% with main axis 45 degrees to the x-axis
%%
ppg = halfcircle scaled 1cm rotated -45 yscaled -0.5
          rotated (45+180) shifted (-5cm,-3cm);
draw ppg;
pph = halfcircle scaled 1cm rotated 90 yscaled -0.5
          rotated (45+180) shifted (-5cm,-3cm);
drawarrow pph;

%%
%% Direction of polarization for linearly polarized light
%%
drawarrow (4cm,0cm)--(4cm+0.707cm/2,0.707cm/2);
drawarrow (4cm,0cm)--(4cm-0.707cm/2,-0.707cm/2);
drawarrow (-5cm,0cm)--(-4.5cm,0cm);
drawarrow (-5cm,0cm)--(-5.5cm,0cm);

%%
%% Indicators for position on the Poincare sphere
%%
pickup pencircle scaled 0.2pt;
draw (3cm,3cm)--(1cm,3cm)--(0.18cm,2.52cm);
draw (3cm,0cm)--(1.8cm,0cm)--(0.95cm,-0.51cm);
draw (3cm,-3cm)--(1cm,-3cm)--(0.18cm,-2.52cm);
draw (-3.6cm,3cm)--(-3cm,3cm)--(-1.65cm,1.65cm);
draw (-3.6cm,0cm)--(-3cm,0cm)--(-2.4cm,-0.18cm);
draw (-3.6cm,-3cm)--(-2cm,-3cm)--(0.65cm,-1.8cm);