Ultrafast all optical beam steering

EPSRC：Justus Bohn：EP/L015331/1非线性光学是研究强激光与物质相互作用的学科。非线性光学现象使广泛的应用，如电信，光束整形和全光数据处理。然而，大多数材料仅表现出极弱的光学非线性，即使在强烈的照明下。因此，非线性光学现象的建立需要长的相互作用长度，并且这些相互作用路径通常通过使用难以按比例放大和集成到纳米光子学系统中的庞大材料结构来获得。因此，非线性光学领域的长期目标是开发具有非常大的非线性响应的材料，其光学性质可以在低功率光场下显著改变。此外，本发明还提供了一种方法，当前的兴趣是由观察到诸如掺锡氧化铟（ITO）的简并半导体表现出极大的增强的非线性特性引起的，这种观察结果表明，掺杂锡的氧化铟（ITO）的简并半导体的非线性特性在很大程度上增强，而掺杂锡的氧化铟（ITO）的非线性特性在很大程度上增强。在电信波长的线性光学响应。自从这些最初的发现以来，已经表明通过在ITO层上利用金天线可以进一步增加效果。这为非线性系统打开了大门，大大减少了相互作用长度，允许更好地集成到纳米光子架构中。目前ITO最重要的应用之一是全光束转向。考虑到材料的亚皮秒响应时间，全光学转向有可能非常快，如果可行，可以大大提高位置扫描系统的速度。在此，ITO与适当设计的纳米天线阵列，提供了一个超薄，高效，全光束转向平台的前景。在这个联合研究项目中，我们的目标是设计，制造和表征所有光开关光束转向样品。在我逗留渥太华期间，我们将开发、优化和制造非线性器件，并在空气中进行第一次表征，这将使我们能够建立基本的非线性行为。回到埃克塞特，我们将充分研究开关的角响应。我们希望这将是更复杂的超颖表面设计的起点，从而实现完全的光束形状控制。

EPSRC : Justus Bohn : EP/L015331/1Nonlinear optics is the study of the interaction of intense laser light with matter. Nonlinear optical phenomena enable a broad range of applications, such as telecommunications, beamshaping and all-optical data processing. However, most materials exhibit only an extremely weak optical nonlinearity, even under intense illumination. Consequently, long interaction lengths are needed for the build-up of nonlinear optical phenomena, and these interaction paths are usually obtained by using bulky material structures that are difficult to scale up and to integrate into nanophotonics systems. As a result, a long standing goal in the field of nonlinear optics has been the development of materials with very large nonlinear responses, whose optical properties can be dramatically changed with a low-power optical field. In addition, it is highly desirable that these materials possess a sub-picosecond time response to reach THz rates and are suitable for nanoscale integration through existing complementary metal- oxide-semiconductor (CMOS) fabrication technologies long established in industry.Current interest is motivated by the observation that degenerate semiconductors such as tin-doped indium oxide (ITO) exhibit a huge enhancement of the non-linear optical response at telecoms wavelengths. Since these initial discoveries, it has been shown that the effect can be even further increased by utilising gold antennas on an ITO layer. This has opened the door to ultrathin nonlinear systems, with greatly reduced interaction lengths allowing for better integration into nanophotonic architectures. One of the most important applications currently being addressed with ITO is all-optical beam steering. Considering the sub-picosecond response time of the material, all-optical steering has the potential to be very fast, and if workable, could provide drastic improvements to the speed of location scanning systems. Here, ITO with properly designed nano-antenna array, offer the prospect of an ultra thin, highly efficient, all-optical beam steering platform. In this joint research project we aim to design, manufacture and characterize all optically switched beam steering samples. We will develop, optimise and fabricate nonlinear devices during my stay in Ottawa, and carry out a first characterisation in air which will allow us to establish the basic nonlinear behaviour. On returning to Exeter, we will fully characterise the angular response of the switching. We hope this will be the starting point of more complex metasurface designs that enable full beam shape control.