IOSR Journal of Applied Physics (IOSR-JAP) e-ISSN: 2278-4861.Volume 11, Issue 1 Ver. II (Jan. – Feb. 2019), PP 48-54 www.iosrjournals.org DOI: 10.9790/4861-1101024854 www.iosrjournals.org 48 | Page Optical properties and optical parameters of chalcogenide optic fiber material based selenium M.M.El-zaidia , Z.H.El-Gohary, M.S.AboGhazala, G.M.Turky* and E.A.Rabea. Phys.Dept. Faculty of science, Menoufia university shebin El.koom,Egypt *Microwave Physics & Dielectrics Department, National Research Centre (NRC),Egypt. Corresponding Author: M.M.El-zaidia Abstract: The nonlinear variation of transmission (T) and reflection (R) as a function of wavelength (ʎ) in the spectral range 200nm – 2500nm for thin film samples of the system Se 80 S 20-x B x where (x=0, 2.5, 5 and B=In or As) was recorded. The maximum transmission intensity was 85% at visible and infrared regions. The top of the transmission peak was at the wavelength 1500nm for Se 80 S 20 sample. The addition of 2.5 at % In on expense of S, leads to the appearance of plateau at a wavelength 1100nm-2500nm. Increasing In content to 5 at %, shift the maximum transmission peaks toward long wavelength (red shift) and located at wavelength 1750nm. Replacing In by As with different ratio, the maximum transmission peak suffered from blue shift. On the other hand, the reflected light intensity was 45 % for the sample Se 80 S 20 at the locations 500nm,900nm and 2100nm. The addition of 2.5 at % In increase the reflection to 50% at the location 500nm and change to be 40% at locations 900nm and1400nm. Increasing In content to 5 at %, keep the reflected intensity 40% at locations 900nm,1400nm and 2100nm. Replacement In by 2.5 at % As on expense S, leads to shift the reflected peak intensity to short wavelength (blue shift). Increasing As content to 5 at %, increase blue shift of the reflected peak to appear at locations 700nm and 900nm with intensity 60%. The addition Er cover layer leads to appear transmission plateau with intensity 80 % for Se 80 S 20 Er and Se 80 S 17.5 In 2.5 Er samples and 60% for the sample Se 80 S 15 In 5 Er. The absorption coefficient is zero at low photon energy high value at high photon energy and moderate values at visible region. The addition of In or As on expense S, lead to decrease the absorption coefficient. This decrement was more detectable in case of adding As. The addition of Er cover layer leads to decrease the absorption coefficient of all sample. The zero or negative value of the extinction coefficient means that very high smooth surfaces of the samples under test. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 13-02-2019 Date of acceptance: 28-02-2019 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction Chalcogenide glasses were attract special interest due to their benefit applications (1-2). Among the amorphous chalcogenide alloys mostly selenium (Se) based material are preferred due to its commercial use. Thin chalcogenide films have found application in the field of optical technology as novel memory devices (3). These films have a high refractive index, low phonon energy and gradually are transport from visible to the infrared region (3). These materials very promising to be use in fiber optics and wave guide devices integrated optics and optical memories (4-5). Moreover, it can be used as core material for optical fiber, for light transmission (6). This means that, this material will be used in communication systems which depends on high- bit rate of transformed high optical date through ultra-fast optical switches (1-3). The nonlinear switching is the most distinctive chalcogenide glasses due to ultra-fast time interval and compatibility with the future fiber technology (4-6). This glassy material is also insensitive to moisture (7-8). This will lead to the appearance of a new category of optic fiber promising applications in the mid-infrared optics (9-11). The aim of the present paper is to study the optical properties of the system Se 80 S 20-x B x where (x=0,2.5,5 and B=In or As). The samples were prepared as thin films using the laser ablation technique. The transmission T, reflection R and the optical parameters as function of wavelength will be recorded. The optical band gap E g opt will also be determined. II. Experimental The chalcogenide samples of the system Se 80 S 20-x B x where (x=0,2.5,5 and B=In or As) were prepared by melting quench technique. Elements Se, S, Te, In& As were weighted and well mixed using the ball milling method for each sample alone. The mixture was placed in an evacuated (10 -4 Pa) and capsulated silica tube. The silica tube containing each sample was heated at fixed temperature for fixed time. The sample Se 80 S 20 and each sample contain In on the expense of S were melted at 500 0 C for 8 hours and quenched in Ice water.