Dynamic studies of the linear optical properties of nanostructured media

我国国民经济的发展、增长和未来将越来越依赖于超出当前技术能力前沿的领域的科学创新。纳米技术就是这样一个领域，它已经在国际上和英国得到了大量的投入，无论是在科学努力还是在财政投资方面。技术能力的进步，包括现代制造技术和纳米结构自组装的新方法，以及结构表征和理论理解的进步，现在正在刺激对近原子尺度、人造、这种特殊的建议涉及纳米结构介质的光学性质，其形式为两种-粒子的三维阵列可能或可能不位于更复杂的多层薄膜结构内。该研究团队将通过自组装过程制造贵金属纳米棒的2D阵列，该过程涉及工业兼容的薄膜加工技术，结合电化学，阳极化和沉积，在纳米级上创建结构物质的方法。该过程将使用各种光学技术进行监控，包括动态，实时椭圆偏振和宽光谱范围内的光度测量。这些将通过全面的制造后处理和额外的光学测量来补充，以收集对其各向异性行为的全面观察。为了理解光学数据，团队将建立有效的介质理论来解释观察到的行为。这将通过调用离散偶极子方法（DDA）来处理单个纳米颗粒的响应及其在微观尺度上相互作用来完成。DDA方法将每个粒子视为等效巨原子的集合，这些巨原子模拟了奇异形状介质的特性，但受到现有计算能力的限制。其目标是开发制造技术，以产生新的介质;并通过扩展或开发新的“基于原子”的数学模型，从理论上观察和理解它们的集体各向异性光学行为。

The development, growth and future of our national economy will become increasingly dependent on scientific innovations in areas that are beyond the cutting edge of current technological capabilities. Nanotechnology is one such area that is already receiving a great deal of input internationally and in the UK, in terms of both scientific effort and financial investment. Advances in technological capability that include modern fabrication techniques and novel approaches to self-assembly of nanostructures, as well as advances in structural characterisation and theoretical understanding, are now stimulating a clear resurgence of interest in the individual and collective behaviour of near atomic-scale, man-made, structures that exhibit new and exciting physical properties.This particular proposal is concerned with the optical properties of nanostructured media in the form two-dimensional arrays of particles that, may or may not, lie within a more complicated multilayered thin film structure. The research team will fabricate 2D arrays of noble metal nanorods by a process of self-assembly that involve, industrially compatible, thin film processing techniques combined with electrochemical, anodisation and deposition, methods for the creation of structured matter on the nanoscale.The processes will be monitored using a variety of optical techniques including dynamic, real-time ellipsometry and photometry over a wide spectral range. These will be complemented by comprehensive post-fabrication processing and additional optical measurements in an attempt to gather a comprehensive set of observations of their anisotropic behaviour.In order to understand the optical data the team will build upon effective medium theories to explain observed behaviour. This will be done by invoking a discrete dipole approach (DDA) to deal with the response of individual nano-particles and their interactions with each other on the microscopic scale. The DDA approach treats each particle as an assembly of equivalent giant atoms that model the properties of odd-shaped media, subject to the limitations of available computing power.The objectives will be to develop the fabrication techniques, with the aim of generating new media; and observe and understand their collective anisotropic, optical behaviour in theoretical terms by extending or developing new 'atomistic-based' mathematical models.