Optics of structured metal layers with liquid crystals

Ebbesen等人在1998年的《自然》杂志上发表了关于穿孔金属薄膜的显著光学传输特性的观察结果，这些穿孔阵列的直径远远小于辐射波长。这项研究随后激发了人们对探索通过各种不同金属结构增强电磁辐射传输的巨大研究兴趣。事实上，整个表面等离子体光学领域都有了巨大的增长，这种增强的透射率只是其中的一部分。人们普遍认为，这种结构的使用在光学芯片技术、光学传感、显示器、有机发光器件[OLED]、单光子光源、新型定向光源、增强的探测器能力等方面具有潜力。几乎所有感知结构的本质都是穿孔金属屏幕(孔或狭缝，实际上通常支持非常不同的电磁行为)和介电薄膜的组合。一般来说，到目前为止所考虑的结构都是无源的，因为它们的介电参数可能不会被调谐。(OLED显然不是被动的，但这只是载波的创造)。当然，如果薄膜介质在光学上是非线性的，并且光场足够强，那么显然存在非线性开关的可能性，但这可能需要高亮度源。在这里，我们希望探索液晶与结构金属薄膜结合使用的潜力，液晶可以通过低电压(如液晶显示器[LCD])改变其光学介电常数。

Ebbesen et al published in Nature in 1998 observations on the remarkable optical transmission properties of metal films perforated with an array of holes which have diameter much less than the radiation wavelength. This study has subsequently stimulated an enormous surge of research interest into the exploration of enhanced transmission of electromagnetic radiation through a variety of different metal structures. Indeed the whole area of surface plasmon optics, of which this enhanced transmission is but a part, has seen massive growth. It is generally perceived that the use of such structures has potential in optical chip technology, optical sensing, displays, organic light emitting devices [OLEDs], single photon sources, novel directed light sources; enhanced detector capabilities etc. The essence of almost all perceived structures is the combination of a perforated metal screen (holes or slits, which actually often support very different electromagnetic behaviour) and thin films of dielectric. Generally the structures considered thus far have been passive in so far as their dielectric parameters may not be tuned. (OLED's are clearly not passive but this is simply carrier creation). Of course if the thin film dielectric is optically non-linear and the optical fields intense enough then there is the obvious possibility of non-linear switching, but this is likely to require high brightness sources. Here we wish to explore the potential for the combined use of liquid crystals, which may have their optical permittivities altered by low voltages (as in liquid crystal displays [LCDs]), combined with structured metal films.