Using inverse Mie calculations to extract size and refractive index of the non-absorbing particles from their polarized light back-scattering intensity measurements

Abstract

Abstract In this paper, we presented the optical technical to extract size and refractive index of the non-absorbing particles. It is based on the inverse Mie for calculating the Mie scattering amplitudes S1 (θ) and S2 (θ) from their measurement of the electromagnetic backscattering linear polarized plane. In this case, we realized a simple experimental setup placed in our laboratory and it focused on three parameters: the incident angle (α), the polarizer (P) and the sample of sands. This optical technical showed the incident light interact with the irregular surface of sample, the polarized light is scattered in the serval backward directions in the space and the backward received signal is measured by a focusing onto a CCD capture in the two backward directions scanning with a 5° scattering setup angle. The experimental data of the polarized scattering intensities i1 (θ) and i2 (θ) was measured by our experimental setup, and they converted to the Mie scattering amplitudes S1 (θ) and S2 (θ). Hence, when those amplitudes are known the Mie coefficients an and bn can be obtained. Then we can extract the refractive index and the radius of the non-absorbing particles at the same time from the Mie coefficients. Then, the physico-chemical properties of the non-absorbing particles calculated and shown to be nearly identical to that of original particles compared with the old instruments. The presented technique is suggested for employing in optical instruments to characterize the nature of surfaces.