Pretreatment Methods for Eliminating the Interference Fringes

Introduction

As already introduced in Application News A313 and A335, interference fringes appearing in film transmission spectra are used for calculating film thickness, because their period vary depending on the light’s incidence angle and the film’s refractive index and thickness. However, interference fringes also affect peak positions and intensities. Therefore, they can impede not only quantitation, but also qualification and identification of unknown substances. This Application News introduces a pretreatment method that will decrease the effect of interference fringes in transmission measurements. Some caution points will be also indicated.

October 30, 2025 GMT