从plasmon到nanoplasmonics——近代光子学前沿及液晶在其动态调制中的应用

本综述首先较为系统地介绍了近代光子学的一个重要分支——纳米等离子激元学(nanoplasmonics)中有关基础概念的物理、光学背景及推动该学科的演绎发展脉络. 这包括由在平滑界面上的光学表面波(optical surface wave)从物理上导出表面等离子激元(surface plasmon polariton, SPP)的概念, 再由粗糙表面及较大金属颗粒对SPP的影响, 引出线度远小于光波长的纳米金属颗粒与光电磁波的相互作用的结果: 本地表面等离子激元(localized surface plasmon polariton)的存在, 亦即纳米等离子激元学的基础. 在简介了纳米等离子激元学器件系统如何在诸多领域突破了传统光学的束缚, 演绎开辟出了近代光学研究的许多特异的新领域后, 特别关注了近期迅速发展并引起越来越多关注的可调制的纳米等离子激元学(tuneable nanoplasmonics)器件的领域. 液晶材料在光学响应方面特有的可调制特性, 使其在纳米等离子激元学器件的调制中成为一个具有非常实用意义的探索方向. 本综述介绍了这方面研究的最新进展, 并对存在的挑战及可能的发展方向等也进行了相应的探讨.

From plasmon to nanoplasmonics-the frontiers of modern photonics and the role of liquid crystals in tuneable nanoplasmonics

This review is intended to be a fundamental lecture. It focuses on systematically introducing the reader to the physical and optical background to certain basic concepts in nanoplasmonics, before devoting attention to the many new developments at the frontiers of modern photonics, such as tuneable nanoplasmonics. There is a special discussion of the advantages and applications of liquid crystals in this area. First, in optics according to the special requirements of an optical surface wave propagating alone a smooth boundary the concept of surface plasmon polariton (SPP) has been introduced from physics. After discussing the influences from more rough surfaces upon the SPP and the response from larger metallic particles to the optical electro-magnetic waves the results from interaction between the optical waves and metallic particles with dimensions much small than the wavelength of the optical waves-the exist of the local surface plasmon polariton, i.e. the base of nanoplasmonics, has been confirmed. Secondly, this review describes many new and interesting aspects from this important branch at the frontiers of modern photonics-nanoplasmonics, which are supported by metamaterials consisting of metallic particles with various shapes and nano-scale size from modern manufacture technologies and more powerful and functional software. Many device system based upon these aspects have broken through the limitations of classical optics and developed in many special new directions, for example the quantum coincidence of lasers-Spaser (surface plasmon amplification by stimulated emission of radiation) etc. Finally, we address tuneable nanoplasmonics, which is a very important topic that has warranted great attention. by reason of liquid crystals’ many special advantages in optical responses-for example their larger optical birefringence, which can be easily modulated by applying electric and/or magnetic fields etc.-the application of liquid crystals in tuneable nanoplasmonic devices is a more practical research direction. This review introduces recent developments in this area, and also discusses various challenges and possible research topics.