The optical constants determination of thin-films

A method for calculating the optical constants of weakly absorbing homogeneous thin films of refractive index, n lower than substrate index, s (s < n) and extinction coefficient, k from the spectral Transmission information alone with no prior knowledge of their characteristics was studied. Initially the procedure uses transmission turning point data to estimate the refractive index, n and extinction coefficient, k by an analytical approach. The calculations are done from the knowledge of transmission turning point data, which was obtained from Shimadzu UV3100 spectrophotometer. The data are then fitted to a high order polynomial function that undergoes an iterative refinement routine by means of a goal seek routine to determine with good accuracy the film parameters as a function of wavelength

Keywords:

optical constants , refractive index , transmission , thin films , turning point and weakly absorbing