Periodic structures for nonlinear optics

非线性光学是用来指光和物质的相互作用的术语，其中相互作用的强度取决于光的强度。在这项研究计划中感兴趣的非线性效应是那些基于高强度激光束引起的折射率变化。这种效应已被用来证明一系列的全光开关和信号处理设备。然而，存在于大多数材料中的相对小的非线性系数导致过高的光功率水平，并限制了这种器件的潜在应用。周期性结构由于其新颖的光学性质而吸引了科学家和工程师几十年。例如，在蛋白石晶体和蝴蝶翅膀中观察到的颜色是由于潜在的周期性结构，而不是色素沉着的结果。这种周期性结构的相关益处之一是它们导致对光的高度限制，并因此使非线性光学相互作用更有效。要克服的挑战是设计周期性结构，这将增强非线性光学相互作用，从长远来看，这将导致实际的全光开关和信号处理设备。本申请的目的是将联合收割机当前和开发的非线性材料与工程化的周期性光子结构相结合，以展示新的全光学功能。此外，将研究使用光学增益是这样的周期性结构，以期进一步降低光功率要求。

Nonlinear optics is the term used to refer to the interaction of light and matter where the strength of the interaction depends on the optical intensity. The nonlinear effects of interest in this research program are those based on the change in refractive index induced by a high intensity laser beam. Such effects have been used to demonstrate a range of all-optical switching and signal processing devices. However, the relatively small nonlinear coefficients present in most materials result in prohibitively high optical power levels and limit the potential applications of such devices. Periodic structures have fascinated scientists and engineers for decades because of their novel optical properties. For example the colors observed in opal crystals and butterfly wings are due to the underlying periodic structures and not a consequence of pigmentation. One of the associated benefits of such periodic structures is that they lead to a high degree of confinement for light and as a result make nonlinear optical interactions more efficient. The challenge to be overcome is to engineer periodic structures which will enhance nonlinear optical interactions and which in the long term will result in practical all-optical switching and signal processing devices. The aim of this application is to combine current and developing nonlinear materials with engineered, periodic photonic structures to demonstrate novel all-optical functionalities. In addition, the use of optical gain is such periodic structures will  be investigated with a view to further reducing the optical power requirements.