Spectral interferometry in thickness measurements of optically transparent layered structures

The authors are exploring the applicability of the optical-band spectral interferometry in thin film thickness measurements. Analytical and experimental methods have been employed to investigate the spectrum of the total irradiation at the output of the fiber optic Fabry-Perot interferometer, being formed by broadband light reflections from multilayer structures, including the special case of two reflections with thin films being the object of study. Useful spectrum components carrying the data on the distance to the reflecting surfaces have been detected. The results of experiments with broadband LED light sources perfectly agree with the theoretical findings. A software tool with a graphical user interface has been developed to process and visualize the experimental data. The obtained results will help improve the performance of the measuring equipment in medicine, profilometry, and create standards for metrology. © 2017 by Begell House, Inc.