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
