function  y=TB(Idata,wvdata)

c1=1.191062e-8; %2hc^2
c2=1.438786;    %hc/kT


ln=length(wvdata)

for l=1:ln
    y(l)=c2*wvdata(l)/log(1+c1*(wvdata(l)^3)/Idata(l));
end