Controlled excitation of quantum emitters by nonlinear plasmonic nearfields

通过非线性等离子体近场控制量子发射器的激发

• 批准号: 415999345
• 负责人: Professor Dr. Markus Lippitz
• 金额: --
• 依托单位: Lehrstuhl für Experimentalphysik III (Nanooptik)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/415999345?language=en
• 关键词: Controlled; excitation; quantum; emitters; nonlinear

Even in the focus of the best microscope objective the optical field resembles a plane wave with a spatially flat wave front. This makes the dipole approximation ubiquitous when modelling the interaction of molecules, quantum dots and proteins with light. Effects beyond this approximation, for example different optical selection rules, are accessible only with optical fields that are curved on a sub-wavelength length scale. Plasmonics is able to generate such sculptured fields by elaborate arrangements of metallic nanostructures. However, the spatial shape of the optical field is rather fixed, as it is defined by the material. This makes it difficult to switch the spatial shape, for example to demonstrate its influence on the excitation spectrum of a large multi-chromophoric system.In this project we propose to use nonlinear plasmonics to overcome this limitation. Nonlinear effects such as third-harmonic generation are boosted by the field enhancement inside plasmonic nanos-tructures. While linear plasmonics is rather well understood, in nonlinear plasmonics still many questions are open. This project contributes to two key questions: How is third-harmonic generation in noble metals connected to the electronic band structure and the occupation function? The answer to this question will allow us to tune the local nonlinear response by, e.g. locally heating the electron gas. The second topic are hybrid nonlinear plasmonic structures in which the locally generated third harmonic will be used to excite single quantum emitters. In combination, our plasmonic nanostructure will act as light source with a spatial arrangement that is controllable on a sub-wavelength length scale by a tailored nonlinearity. We envision placing large multichromophoric systems with spatially extended excited states near this light source, such as light-harvesting complexes or H aggregates. Our novel light source will allow spectroscopy beyond the dipole approximation which we expect to shed light on, e.g. the role of quantum coherence in biological systems.

即使在最好的显微镜物镜的焦点上，光场也类似于具有空间平坦波前的平面波。这使得偶极近似在模拟分子、量子点和蛋白质与光的相互作用时无处不在。超出这种近似的效果，例如不同的光学选择规则，只有在亚波长长度尺度上弯曲的光场才能达到。等离子体能够通过金属纳米结构的精心布置来产生这种雕刻场。然而，光场的空间形状是相当固定的，因为它是由材料限定的。这使得它很难切换的空间形状，例如，以证明其对激发光谱的一个大的多色系统的影响。在这个项目中，我们建议使用非线性等离子体来克服这一限制。非线性效应，如三次谐波产生的增强等离子体纳米结构内部的场。虽然线性等离子体是相当好的理解，在非线性等离子体仍然有许多问题是开放的。该项目有助于解决两个关键问题：贵金属中的三次谐波产生如何与电子能带结构和占据函数联系起来？这个问题的答案将使我们能够调整局部非线性响应，例如局部加热电子气。第二个主题是混合非线性等离子体激元结构，其中本地产生的三次谐波将用于激发单量子发射器。在组合中，我们的等离子体纳米结构将充当具有空间布置的光源，该空间布置通过定制的非线性在亚波长长度尺度上是可控的。我们设想在该光源附近放置具有空间扩展激发态的大型多发色团系统，例如捕光复合物或H聚集体。我们的新光源将允许光谱学超越偶极近似，我们希望阐明，例如量子相干在生物系统中的作用。