Mie Scatting Theory Study On Interaction Between Light Wave And Particle And Microcosmic Calculation About Optical Properties Of The New Compound Li₄CaB₂O₆

Mie scatting theory may strictly compute interaction of light-wave with the homogeneous medium ball. At present, Mie scatting theory is applied in the fields of iatrology, atmospheric pollution, scatting of atmospheric particle and so on. This paper carefully depicts the simulating of the Mie scatting theory, and calculates the scattered light field intensity using the programme compiled by Fortran language. The most peak value of scattered light field intensity changes with the real of relative refractive index (except 0°and 180°), but it doesn't change with the image and scale parameters of the ball. All these accord to the fact that the real of relative refractive index plays a part in delaying phasing and the image acts in absorption. In this paper, the optical path is designed to measure the refractive index of high refractive glass bead, using geometric optics and Mie scatting theory. This provides a simple, convenient, cheap method to measure refractive index with expected precision.Recently, the demand for the ultraviolet nonlinear optical crystals is soaring by the developing of optical communications and micro-electronics etc. This paper has computed optical properties of a new compound Li₄CaB₂O₆ based on density functional theory (DFT) and plane wave pseudopotential. During the calculation, wave function is expanded in terms of plane wave basis functions in the condition of periodic boundary; the Perdew-Wang (PW91) of generalized gradient approximation (GGA) is employed in the electronic exchange-correlation function; Norm-Conserving- pseudopetential (NCPP) is applied in atomic potential function. Firstly, crystal cell was optimized by Broyden-Flecher-Goldfarb-Shanno (FBGS), and a local stable structure was obtained. The calculated structure parameters have a good agreement with the experimental data. So from these parameters we can get reliable optical properties. Seen from the curves of reflectivity, absorption coefficient, refractive index, loss function, conductivity and dielectric function, the peaks and abrupt change parts of curves lie in ultraviolet range. This indicates that the new compound Li₄CaB₂O₆ is a good ultraviolet optical crystal. The results provide a good reference for the experimentation and application of the Li₄CaB₂O₆ crystal.