Measurement & evaluation of some optical properties of some materials in near IR region

Abstract

In this work transmitted intensity through some material was measured using laser wavelengths (940 & 810) nm in the near infrared region then the absorption coefficients of these materials were determined and evaluated. The selected materials divided into three groups: group one for Aluminium oxide (Al2 O3 ), group two for magnesium carbonate (MgCO 3 ), group three for nickel oxide (Nio), from each group six discs with different thickness was fabricated using pressing machine. Materials are undergoes spectroscopical analysis using the (ELICO, SL, 153) NIR spectrometer. Two sources of lasers were used to irradiate the discs; diode laser (λ=940nm, P=4W), diode laser (λ=810nm, P=2W), and then the incident (I 0) and transmitted (I) intensity were detected and the values of them was recorded through a digital voltmeter. The relation between log (I/I0) and the thickness of the disc was plotted, and the absorption coefficient of these materials at this wavelength was determined. The results reveals that; group one (Al 2O3 ) has law absorption coefficient (0.119 & 0.210)cm-1 at wavelengths (940 & 810nm) respectively so it can be used to fabricate filters at these wavelengths with high efficiency, group two (MgCO3) has law absorption coefficient (0.185 & 0.194)cm -1 at wavelengths (940 & 810)nm respectively so it can be used to fabricate filters at these wavelengths with high efficiency, group three (NiO) has high absorption coefficient (7.111 & 5.448)cm-1 at wavelengths (940 & 810)nm respectively so it ‫‪at wavelength 940 nm with high‬‬ ‫‪can be used to fabricate attenuators‬‬ ‫‪efficiently, and at wavelength 810nm with moderate efficiency‬‬ ‫.‪The results were coincides to a great extend with materials spectra‬‬

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