Iterative method to extract refractive index value

Hello,

I am new to Matlab, so need some help here.

My equation is a complex transfer function :

H(w) = (4*ns*n0/(ns*n0)^2)*exp(-j(ns-n0)*w*l/c)

I have to extract the value of ns

H(w) is my transfer function = fft(sample)/fft(reference)

n0 is 1 (refractive index of air)

l is the length of the material

c is the speed of light

As far as my basic understanding goes, this could be solved by estimating a range for ns and then running some iterations to reach to the actual value of ns. However, I am confused with the coding part.

[Prasobhkumar P. P.]

Please share the reference of the equation you mentioned