Optics and Photonics Society of Iran

In measuring the particle size by optical techniques, laser diffraction has become popular due to its wider size range as well as accuracy. In this paper, the size measurement of spherical silica nanoparticles suspended in water using laser diffraction method was performed. The shape and size of particles in measuring by laser diffraction technique is very important. The shape of silica nanoparticles used in this study is almost spherical and the particles have a size within the range of 300 to 400 nm. Based on "Mie" theory, the scattered light was also calculated and the results were compared with those of experiment. The particle size was estimated by using the experimental and calculation results.