| Summary: | 碩士 === 國立虎尾科技大學 === 光電工程系光電與材料科技碩士班 === 99 === In arriving at the more intuitive “scattering form” of the Fresnel equations, microscopic physical electric and magnetic dipoles were rigorously employed as the sources of EM waves by Doyle et al. Motivated by such an approach, the authors started to speculate how the incorporation of permanent dipoles might affect the Brewster angle of a specific optical material. It is found that in the presence of permanent dipoles, not only is the Brewster angle dependent on the incident light power as well as the dipole orientation, but also that two conjugate incident light paths result in distinctively different refractions.
Experiments on dipole-engineered PVDF (polyvinylkidene fluoride) films show that by way of adding/reducing permanent dipole density and varying orientations, the aforementioned theoretical predictions can be evidenced unambiguously in the visible light range. Further, new effective polarization density can be quantified from the above experiments subjected to different dipole engineering processes. As a result, the traditionally elliptic contour of a slanted section of the 3D refractive index ellipsoid now manifests symmetric open splittings at large incident angles. It implies that severe challenge to the accuracy of traditional surface plasmon resonance (SPR) measurements may arise in the presence of permanent dipoles of various morphologies, such as in the form of nano-particles.
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