Search

The zero order generalized Morse wavelet was proposed as a method to determine the refractive index and extinction coefficient dispersions of an absorbing thin film in the visible and near infrared regions at room temperature. The generalized Morse wavelet has two degree of freedom and the advantages and disadvantages of additional degree of freedom were discussed in the simulation works. The simulation studies were based on the mean relative error and Cauchy coefficients comparisions, and accuracy of the calculated refractive index was improved by the presented method, were compared with the Morlet wavelet and Paul wavelet. Also, the noise immunity of the method was discussed. The experimental validity of the method was tested on a cadmium sulfide absorbing thin film and the calculated refractive index were cross checked with the value of envelope method and literature.

The continuous wavelet transform with Paul wavelet was proposed as a method for the simultaneous determination of physical thickness and refractive index dispersion of dielectric films in the visible and near infrared region. Transmittance spectrums, acquired at two different incident angles, were used for the calculations. By this way refractive index dispersion was obtained without knowing the film thickness. The method was tested with simulated data and experimentally applied to a sample of borosilicate glass. The obtained thickness and refractive index dispersion values were compared to the values obtained by the envelope method and the ones provided by the manufacturer.

The continuous wavelet transform (CWT) using the Gabor wavelet was applied to analyze the transmittance signal. Transmittance spectra of a mica film and 4-cyano 4′-pentyl biphenyl liquid crystal were acquired in the visible spectral region by using a monochromator, and the dispersion curves of the refractive index and the birefringence were deduced. The experimental data were fitted to the Cauchy's formula, and the dispersion parameters were extracted. The results obtained by the CWT approach were compared with the published values.