Study of Light Propagation in Chained Dielectric Spheres

• Main Authors: Jih-Hui Hsu, 徐日輝
• Other Authors: Ming-Shan Tsai
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/38306522420170001072

碩士 === 國立嘉義大學 === 電子物理學系光電暨固態電子研究所 === 100 === Our experimental purpose is to observe the light propagation of single polystyrene（PS）micro-spheroid and chained PS micro-spheroids. Based on the theories, the focusing modes of such light propagation are related to the diameter and refraction index of the micro-spheroid. Thus, a method was developed in this experiment to appropriately modulate the diameter and refraction index of the PS micro-spheroid by a heating treatment. With a sequence of observations in different temperature, the light propagation of the micro-spheroid could be accurately described. We found that the relative intensity（ ）of the light propagating in the PS micro-spheroid declined with the increase in the ambient temperature, and the declination had a maximum at 350 . According to the nanojet-induced modes（NIMs）, we considerably inferred to the heating treatment caused an increase in the refraction index of the PS micro-spheroid and altered the focusing modes of the propagation light. This resulting could be proved by the position of the focusing point, which slightly shifted to the core of the PS micro-spheroid. In the experiment of observing the light propagation in chained PS micro-spheroids, we found that the contact points between the micro-spheroids were melting during the heating process. This resulting would induce a declination of the light focusing in the PS micro-spheroids. With more time used in heating the micro-spheroids, the light propagation gradually became a simple waveguide which scattered light with lager solid angles in the exit. Our experimental results could be explained by NIMs theory.