ABSTRACT

Light is electromagnetic radiation in the wavelength range from 3 nm to 30 µm. Visible light is the part of electromagnetic radiation to which the human eye is sensitive, and the wavelength of it ranges from 400 nm to 750 nm. The scattering phenomenon of light includes diffraction, deflection, and refraction of light. Mie used electromagnetic theory to obtain the rigorous solution of light scattering by a uniform and spherical particle. The light scattering technique is nowadays one of the typical particle size analysis methods. Dynamic light scattering has been used for the size measurement of particles between about 3 nm and 5 µm in diameter. Several techniques have been developed for dynamic light scattering. These techniques can be classified in two ways: by the difference in data analysis and by the difference in optical setup. The photophoresis force depends on the light intensity and wavelength, the size, shape, and material of the particle, and the gas pressure.