jreftran - A layered thin film transmission and reflection coefficient calculator

This script calculates the reflection and transmission coefficients for a thin film stack.

This program produces the complex reflection and transmission coefficients of a multilayer stack given the angle of incidence, polarization, wavelength, complex-refractive index of each layer, and thickness of each layer. The program assumes lossless dielectric incident and exit media but the film layers may be lossy (which is accounted for by the complex nature of the refractive index). The program also assumes that all layers are non-magnetic. Magnetic media can be handled by more general theory (see technical report cited below).
This program is based on the technical report written by K. Pascoe,
"Reflectivity and Transmissivity through Layered, Lossy Media: A
User-Friendly Approach," 2001. See the following link for the technical
paper:
http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA389099
usage:
[r,t,R,T,A]=jreftran_rt(l,d,n,t0,polarization)
where
l = free space wavelength, in nanometers
d = layer thickness vector, in nanometers
n = layer complex refractive index vector
t0= angle of incidence
polarization should be 0 for TE (s-polarized), otherwise TM (p-polarized)
r = reflection coefficient
t = transmission coefficient
R = reflectivity (fraction of intensity that is reflected)
T = transmissivity (fraction of intensity that is transmitted)
A = absorptivity (fraction of intensity that is absorbed in the film stack)
Note:
The layer thickness vector "d" should be the same length as the refractive index vector, even though the first and last entries are not used.
Example: Finding the coefficients for a 200nm gold layer surrounded by air, using the Johnson and Christy data
input:
[r,t,R,T,A]=jreftran_rt(500,[NaN,200,NaN],[1,0.9707 + 1.8562i,1],0,0)
output:
r = -0.4622 - 0.5066i

t = -0.0047 + 0.0097i

R = 0.4702

T = 1.1593e-04

A = 0.5296