Higher-order mode manipulation through fiber-interfaced metastructures for nonlinear frequency conversion applications

通过光纤接口元结构进行高阶模式操纵，用于非线性频率转换应用

• 批准号: 515003543
• 负责人: Professor Dr. Markus A. Schmidt
• 金额: --
• 依托单位: Leibniz-Institut für Photonische Technologien (IPHT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/515003543?language=en
• 关键词: Higher; order; mode; manipulation; through

Higher-order modes (HOMs) in fibers have recently attracted substantial attention due to their unique potential in highly topical areas. One of these areas is nonlinear frequency conversion, in which HOMs allow, for example, access to hard-to-reach dispersion landscapes or the exploration of previously inaccessible nonlinear effects. The key challenge here is to efficiently excite or convert HOMs to achieve the highest possible mode purity or to exclusively excite a desired mode. The slightest deviation in modal properties can lead to erroneous results, making precise control of beam properties essential. A cutting-edge approach for shaping beams is based on dielectric nanostructures. The two concepts followed in this project are holograms and metasurfaces, both of which allow shaping of intensity and phase profiles, with metasurfaces additionally capable of controlling polarization. Thus, the combination of dielectric nanostructures and optical fibers suggest a unique control over HOMs in the context of fiber-based nonlinear frequency conversion. This project is dedicated to dielectric metastructures located on the end faces of optical fibers, used in the context of HOM-based ultrafast nonlinear frequency conversion. The unique beam shaping capabilities of holograms and dielectric metasurfaces are exploited here to shape and transform optical beams in terms of intensity, phase and polarization. This is applied in the project to two nonlinear effects, namely third harmonic generation (THG) and supercontinuum generation (SCG). In addition to intensity, shaping phase and polarization is essential, which directly manipulates the electric field as opposed to purely intensity modulating concepts. The THG experiments address the transformation of complex phase-matched HOMs at visible wavelengths into linearly polarized beams with Gaussian profiles. Furthermore, fiber-interfaced metastructures are used for broadband SCG in desired HOMs with complex polarization distributions. The project includes design, simulation, implementation and optical characterization. For the realization of the metastructures on fiber end faces, two methods established and successfully used at the applicant's institute (3D nanoprinting, modified electron beam lithography) are applied. Overall, the project defines a novel photonic platform that not only opens a new field of application for metastructures - metastructure-enabled nonlinear fiber photonics - but also enables the investigation of otherwise difficult-to-access nonlinear effects in fibers with application in a variety of cutting-edge fields.

纤维中的高阶模（HOM）由于其在高度热门领域的独特潜力，最近引起了人们的广泛关注。其中一个领域是非线性频率转换，其中HOM允许访问难以到达的色散景观或探索以前无法访问的非线性效应。这里的关键挑战是有效地激励或转换HOM，以实现最高可能的模式纯度或专门激励所需的模式。模态特性中最微小的偏差都可能导致错误的结果，因此必须精确控制梁的特性。一种用于成形光束的尖端方法是基于电介质纳米结构。在这个项目中遵循的两个概念是全息图和超颖表面，两者都允许强度和相位分布的成形，超颖表面还能够控制偏振。因此，介电纳米结构和光纤的组合表明在基于光纤的非线性频率转换的背景下对HOM的独特控制。该项目致力于位于光纤端面的介电亚结构，用于基于HOM的超快非线性频率转换。利用全息图和电介质超颖表面独特的光束整形能力，在强度、相位和偏振方面对光束进行整形和变换。这在项目中应用于两个非线性效应，即三次谐波产生（THG）和超连续谱产生（SCG）。除了强度之外，成形相位和偏振是必不可少的，其直接操纵电场，而不是纯粹的强度调制概念。三次谐波实验解决了在可见光波长的复杂相位匹配的HOM到高斯分布的线偏振光束的转换。此外，光纤接口的亚结构用于宽带SCG在所需的HOM与复杂的偏振分布。该项目包括设计，仿真，实施和光学特性。为了在光纤端面上实现亚结构，应用了在申请人的研究所建立并成功使用的两种方法（3D纳米打印、改进的电子束光刻）。总的来说，该项目定义了一个新的光子平台，不仅为元结构开辟了一个新的应用领域-元结构使能的非线性光纤光子学-而且还能够研究光纤中难以获得的非线性效应，并应用于各种尖端领域。