【摘要】：在外界光場(chǎng)的驅(qū)動(dòng)下,金屬納米顆粒表面自由電子能夠集群運(yùn)動(dòng),形成局域表面等離子激元振蕩(localized surface plasmons resonance)。這種振蕩模式能夠強(qiáng)烈地捕獲入射光并將其轉(zhuǎn)化為熱能,形成納米熱源,由于其產(chǎn)熱效率高、操控靈活、高度局域化等特點(diǎn),成為表面等離激元光學(xué)研究的一個(gè)重要方向。在癌癥治療、化學(xué)催化、熱成像、熱調(diào)制、光學(xué)吸收器等領(lǐng)域顯示出光明的應(yīng)用前景。同時(shí),由納米熱源激發(fā)的一系列微秒的物理化學(xué)過程也引起人們的極大興趣,而要操控這些過程,就需要能動(dòng)態(tài)地遠(yuǎn)程控制納米尺度空間上的溫度分布。在本文中,我們利用金屬納米顆粒組裝體獨(dú)特的光學(xué)性質(zhì),提出了一種能靈活調(diào)控納米尺度空間溫度分布的方法。我們發(fā)現(xiàn)通過旋轉(zhuǎn)入射光的偏振方向,可以在等離激元組裝體中動(dòng)態(tài)地分配熱源,從而引導(dǎo)納米尺度空間上的溫度重新定位和分布。本文主要做了兩方面的工作。第一個(gè)方面研究了納米顆粒集群的光學(xué)性質(zhì)。首先研究了二聚體的光學(xué)性質(zhì),發(fā)現(xiàn)其支持的gap模式吸收強(qiáng)度對(duì)偏振方向非常敏感；接著以三聚體為例,全面研究了三聚體光學(xué)吸收特性,發(fā)現(xiàn)在gap模式的共振波長(zhǎng)上,三個(gè)球體呈現(xiàn)出很大吸收對(duì)比度,而這種吸收對(duì)比度由偏振方向決定,由此可以通過調(diào)節(jié)入射光偏振方向來分配三個(gè)顆粒之間的熱量。第二個(gè)方面研究了納米顆粒組裝體在吸收光能后的熱傳輸效應(yīng)。計(jì)算了三聚體顆粒溫度分布,發(fā)現(xiàn)在納米尺度的間隔內(nèi),三個(gè)顆粒之間仍然可以實(shí)現(xiàn)很大的溫度差值。接著研究了三聚體結(jié)構(gòu)參數(shù)變化對(duì)顆粒之間溫度差值的影響,發(fā)現(xiàn)顆粒之間的溫度差值不僅僅由吸收的能量差值決定,相互之間的熱交換也起著很大的作用。實(shí)現(xiàn)納米尺度空間溫度分布調(diào)控為遠(yuǎn)程操控由納米熱源激發(fā)的一系列物理和化學(xué)過程提供了可能。
[Abstract]:Driven by the external light field, free electrons on the surface of metal nanoparticles can cluster to form a local surface plasmon oscillating (localized surface plasmons resonance). This oscillating mode can capture incident light intensively and convert it into heat energy to form nanometer heat source. Due to its high thermal efficiency, flexible manipulation and high localization, it has become an important research direction of surface isoexciter optics. In cancer treatment, chemical catalysis, thermal imaging, thermal modulation, optical absorbers and other fields show bright application prospects. At the same time, a series of nanosecond physical and chemical processes excited by nano-heat sources have aroused great interest. To manipulate these processes, it is necessary to control the temperature distribution in nanoscale space remotely. In this paper, we propose a flexible method to control the spatial temperature distribution of metal nanoparticles by using the unique optical properties of metal nanoparticles. We find that by rotating the polarization direction of incident light, the heat source can be dynamically distributed in the isophosphate assembly, thus leading to the relocation and distribution of temperature in the nanoscale space. This paper mainly does two aspects of work. In the first aspect, the optical properties of nanocrystalline clusters are studied. The optical properties of the dimer are studied, and the absorption intensity of the gap mode supported by the dimer is found to be very sensitive to the polarization direction, and then the optical absorption characteristics of the trimer are studied comprehensively, and it is found that the absorption intensity of the gap mode is at the resonance wavelength of the gap mode. The three spheres exhibit a large absorption contrast, which is determined by the polarization direction, so that the heat between the three particles can be allocated by adjusting the polarization direction of the incident light. In the second aspect, the heat transfer effect of nanocrystalline assembly was studied after absorbing light energy. The temperature distribution of trimer particles is calculated and it is found that the temperature difference between the three particles can still be realized within the nanoscale interval. Then the influence of trimer structure parameters on the temperature difference between particles is studied. It is found that the temperature difference between particles is determined not only by the energy difference but also by the heat exchange between particles. It is possible to remotely manipulate a series of physical and chemical processes excited by nanoscale heat sources.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.1

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本文編號(hào)：2195636