In our research Hyper-Rayleigh scattering (HRS) is employed as an effective, simple investigation technique to study solutions of small molecules, pure liquids, nano-adsorbing systems and metal colloids. A set of apparatus has been built with good spectral resolution and high sensitivity to successfully measure characteristics of intensity and polarization properties of HRS. It was found that the consistency was different for pure liquid and solutions of small molecules when comparing experimental measurements of depolarized ratios and polarization patterns with theoretical expectations. This is due to the presence of both incoherent and coherent contributions to HRS in pure liquids, of which the origin of the coherent contribution is different for different pure liquids. In our results, pure liquid nitrobenzene was found to have strong coherent contribution to HRS caused by intermolecular interactions. Three different chemical compounds were used to mix with nitrobenzene to break the strong orientational correlations between molecules. Comparison between the results show different behaviors in the effectiveness in eliminating the coherent HRS signals, and the effectiveness was correlated to the molecular structures. Theory of second harmonic scattering from surface has been expanded as leading order contributions containing nonlocal electric dipole mode and local quadrupole mode, which can be exhibited in our experimental study of polarization patterns. Polarization patterns from polystyrene particles of different sizes adsorbed with different species of dyes were measured to investigate and compare with theoretical expectations. For small-size adsorbing system, measurements of polarization patterns were basically consistent with theory. However, for adsorbing system of polystyrene particles with a size of 900 nm, the polarization patterns showed discrepancies when comparing with theory, which indicated that higher order multipoles are needed in the theory. Silver and gold colloids were employed as the subject of investigation for measuring the polarization patterns of HRS. The results were found to be consistent when comparing with their extinction spectra and TEM images. We have managed to measure polarization patterns of HRS originated from surface of non-spherical colloids and the results showed that the origin of HRS can be qualitatively understood, although a more elaborated theory is needed to describe the data. / by Chen, Ji = 由有機液體以及金屬膠體產生的非線性光散射的研究 / 陳佶. / Source: Dissertation Abstracts International, Volume: 70-09, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 117-118). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307. / by Chen, Ji = You you ji ye ti yi ji jin shu jiao ti chan sheng de fei xian xing guang san she de yan jiu / Chen Ji.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_344429 |
| Date | January 2009 |
| Contributors | Chen, Ji, Chinese University of Hong Kong Graduate School. Division of Physics. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, theses |
| Format | electronic resource, microform, microfiche, 1 online resource (xi, 118 leaves : ill.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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