基于金属纳米颗粒光热效应的空间温度分布调控
发布时间：2018-08-21 11:55
【摘要】：在外界光场的驱动下,金属纳米颗粒表面自由电子能够集群运动,形成局域表面等离子激元振荡(localized surface plasmons resonance)。这种振荡模式能够强烈地捕获入射光并将其转化为热能,形成纳米热源,由于其产热效率高、操控灵活、高度局域化等特点,成为表面等离激元光学研究的一个重要方向。在癌症治疗、化学催化、热成像、热调制、光学吸收器等领域显示出光明的应用前景。同时,由纳米热源激发的一系列微秒的物理化学过程也引起人们的极大兴趣,而要操控这些过程,就需要能动态地远程控制纳米尺度空间上的温度分布。在本文中,我们利用金属纳米颗粒组装体独特的光学性质,提出了一种能灵活调控纳米尺度空间温度分布的方法。我们发现通过旋转入射光的偏振方向,可以在等离激元组装体中动态地分配热源,从而引导纳米尺度空间上的温度重新定位和分布。本文主要做了两方面的工作。第一个方面研究了纳米颗粒集群的光学性质。首先研究了二聚体的光学性质,发现其支持的gap模式吸收强度对偏振方向非常敏感；接着以三聚体为例,全面研究了三聚体光学吸收特性,发现在gap模式的共振波长上,三个球体呈现出很大吸收对比度,而这种吸收对比度由偏振方向决定,由此可以通过调节入射光偏振方向来分配三个颗粒之间的热量。第二个方面研究了纳米颗粒组装体在吸收光能后的热传输效应。计算了三聚体颗粒温度分布,发现在纳米尺度的间隔内,三个颗粒之间仍然可以实现很大的温度差值。接着研究了三聚体结构参数变化对颗粒之间温度差值的影响,发现颗粒之间的温度差值不仅仅由吸收的能量差值决定,相互之间的热交换也起着很大的作用。实现纳米尺度空间温度分布调控为远程操控由纳米热源激发的一系列物理和化学过程提供了可能。
[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.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1
[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.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1
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