“…The optical constants n(λ) and k(λ) of our films have been determined using Swanepole technique (Swanepoel, 1984). Our earlier work (El-Bana & Fouad, 2017;El-Bana et al, 2016;Sharma, El-Bana, Fouad, & Sharma, 2016) and various other researchers (Márquez, González-Leal, Jiménez-Garay, Lukic, & Petrovic, 1997;Sharma, Sharda, Sharma, & Sharma, 2014) have used this technique to estimate the optical parameters for chalcogenide glasses. The determined values of n and k for all films were found to lie within the range of the experimental error ±2% for n and ±5% for k (Fouad et al, 2006).…”