Determining Refractive Index Function of Amorphous Materials
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
An absorbance (infrared) spectrum (As), real or complex, is obtained by using a standard Fourier transform (FT) infrared spectrometer, such as the IR/98 made by IBM, and can be used to determine the refractive index of most materials. If As is real, then the Hilbert transform is applied directly to the spectrum. If As is complex, then the spectrum must be divided into two arrays, one imaginary and one real, prior to applying the Hilbert transform. The complex array is divided into its component real and imaginary arrays and manipulated as follows: 1. The complex absorbance spectrum, As, of the sample material is saved. 2. An inverse Fourier transform is performed on the absorbance spectrum. 3. Real and imaginary points in the resultant digitized array are separated.