mie_1.m

MieMatlabMaetzler.zip 非常全功能的Mie散射程序 matlab

function result = Mie_1(m, x)
% Rayleigh Approximation of Mie Efficiencies for given 
% complex refractive-index ratio m=m'+im" 
% and size parameter x=k0*a, k0= wave number in ambient medium,  
% a=sphere radius using the low-frequency approximation of the 
% complex Mie Coefficients an and bn for n=1, p. 131 
% in Bohren and Huffman (1983) BEWI:TDD122.
% Result is m', m", x, efficiencies for extinction (qext), 
% scattering (qsca), absorption (qabs), backscattering (qb), 
% asymmetry parameter asy=<costeta> and qratio=qb/qsca.
% Uses the function "mieab_1" for the Mie Coefficient a1.
% C. M鋞zler, May 2002.

if x==0
    result=[0 0 0 0 0 1.5];
elseif x>0
    nmax=1; n=1; cn=2*n+1; x2=x*x;
f=mieab_1(m,x);
anp=real(f); anpp=imag(f);
dn=cn.*anp;
qabs=2*dn/x2;
en=cn.*(anp.*anp+anpp.*anpp);
qsca=2*en/x2;
qext=qabs+qsca;
q=-cn.*f;
qb=q*q'/x2;
qratio=qb/qsca;
asy=0;
result=[qext qsca qabs qb asy qratio];
end;