AlN thin films deposited onto glass slides using a RE reactive sputtering system at various nitrogen concentrations. Characterizations of the deposited thin films were realized using X-ray diffraction (XRD), atomic force microscopy (AFM) and Uv-Vis spectrophotometer. Morphological and optical properties of deposited films were strongly depend on nitrogen concentration in Ar-N-2 mixed gas plasma. It was shown that deposited AlN thin films were in the amorphous structure except for x=0.4 concentration. The formation of AlN (111) and AlN (220) deposited at x=0.4 concentration were confirmed by XRD studies. Optical properties of deposited AlN thin films were investigated by measuring the transmittance spectra. Transparencies of the deposited AlN films at x=0.4 and 0.3 shown highest transparency concentrations were exhibit approximately similar to 100% in near infrared regions. Also, refractive indexes of the deposited AlN thin films were change by nitrogen concentrations. As s result, deposited AlN thin films will be use antireflection coatings for optical components.