FABRICATION OF CuO DISKS TO ATTENUATE AND FILTER SOME VISIBLE AND I.R. WAVELENGTHS

Abstract

The main objective of this work is to design and fabricate suitable optical attenuators and filters for some wavelengths in the visible and the infrared regions of the electromagnetic spectrum. Selection of the attenuators materials was based mainly on the pre- spectroscopic investigations of these materials. These had been carried out using: UV-VIS. spectrophotometer, NIR spectrophotometer, and FT-IR spectrometer. Using a classical pressing machine, copper oxide disks had been synthesized after mixing with potassium bromide. Two sets of disks were produced : a set with different concentrations of the CuO and constant physical thickness, and a set with different physical thicknesses and fixed concentration of CuO. The produced disks were rigid enough to be dealt with. Using a photodetector, accompanied with digital multimeter, intensity attenuation measurements of these two sets for the wavelengths : 675, 820, and 1064 nm, were carried out. Graphs were plotted from the results and the absorptivities were calculated in each case showing a good liability of using these disks as good optical attenuators for the three tested laser beams at normal angle of incidence. It was noticed that the performance of the second set, with constant concentration of CuO, was better than the performance of the first set. This is because of the constant reflectance of the second set. The spectral performance, extending from 200 to 25000 nm, of these disks were investigated. An optical pass-band filter in the middle IR region (2.5 – 25 μm) at wavelength (λm ~ 15.2 μm) with bandwidth of (Δλ0.5 ~ 1.9 μm), and an absorption neutral density filter in the range: (2.5 ~ 10.0 μm) was obtained from the same materials and the same fabricated disks. Based on the obtained results, some future works were suggested.