Refractive index measurements of planar chalcogenide thin film

We report on the measurements of the refractive index of As–S–Se chalcogenide glasses near 1.55 μm. The measurements were made on annealed and non-annealed samples of thermally evaporated thin films. The data for two different series of glasses are presented: the compositions As 40S 60− x Se x and the compositions As x S (100− x)/2 Se (100− x)/2 where the ratio of sulfur to selenium is kept constant (1:1). It has been found that replacing sulfur by selenium in the first series increases the refractive index from 2.4 to 2.8 and increasing the arsenic content in the second series increases the refractive index. In all cases, it has been found that annealing the samples increase the refractive index. The accuracy in the refractive index measurement is ±0.2%.