function M=FresMueller(Teta,nref)
% Reflection Matrix 
% based on fresnel reflaction
[R,Rl,Rr]=fresnel(Teta,nref)
S1=sqrt(Rr);
S2=sqrt(Rl);
S3=0;
S4=0;
M=mueller(S1,S2,S3,S4);